- ID:
- ivo://CDS.VizieR/J/AJ/152/227
- Title:
- BV(RI)c light curves of NSVS 5066754
- Short Name:
- J/AJ/152/227
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVR_c_I_c_ light curves of NSVS 5066754 were taken on 2014 May at Dark Sky Observatory in North Carolina. This variable is a solar-type eclipsing binary (T1~5750K) with a period of only 0.3751689(1) days. It appeared to be one of the shortest periods in Shaw's list of near-contact binaries. The Binary Maker fits and our Wilson-Devinney solutions show that the binary could have both semidetached and marginal contact binary configurations. Five new times of minimum light were calculated, along with two minima determined from archived All Sky Automated Survey observations. From these minima and the discovery epoch, a quadratic ephemeris was determined. Thus, a magnetic braking scenario is possible. Both semidetached and contact models were explored. A marginal contact solution had the best sum of square residuals. It gave a mass ratio of ~0.5, and a component temperature difference of ~360K, albeit somewhat large for a contact binary. Two substantial cool spots were determined in this solution with 37{deg} and 28{deg} radii and t-factors or 0.94 and 0.78 respectively. The fill-out is very shallow, ~106%. It may have recently achieved contact.
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- ID:
- ivo://CDS.VizieR/J/AJ/145/14
- Title:
- BV(RI)c light curves of V1043 Cas
- Short Name:
- J/AJ/145/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Complete Bessel BVR_c_I_c_ light curves of V1043 Cassiopeia [2MASS J00371195+5301324, Mis V1292, USNO-A2.0 1425-00875743, {alpha}(2000)=00^h^37^m^11.95^s^, {delta}(2000)=+53{deg}01'32.5"] are analyzed. The system is a member of the small group of pre-contact W UMa binaries (PCWBs). Its light curve has the appearance of an Algol (EA) light curve, however it is made up of dwarf solar type components in a detached mode with a period of only 0.6616days. The analysis includes a period study, an improved ephemeris, a mass ratio search, and a simultaneous BVR_c_I_c_ Wilson-Devinney solution. We document about 20 other PCWBs given in the literature. Several have RS CVn-like properties.
- ID:
- ivo://CDS.VizieR/J/AJ/147/3
- Title:
- BV(RI)c light curves of V2421 Cyg
- Short Name:
- J/AJ/147/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first precision BVRI light curves, synthetic light curve solutions, and a period study for the high amplitude solar type binary, V2421 Cygni. The light curves have the appearance of an Algol (EA) type; however, it is made up of dwarf solar type components in a detached mode with a period of only 0.6331 days with an amplitude of about a full magnitude, i.e., it is a precontact W UMa binary. Flare-like disruptions occur in the light curves following the primary and secondary eclipses possibly due to the line-of-sight track of a gas stream. An associated stream spot and splash spot cause bright equatorial spots on the stellar surface of the primary star. The more massive star is the gainer, making this system a classic, albeit dwarf, Algol.
- ID:
- ivo://CDS.VizieR/J/MNRAS/392/1181
- Title:
- BV(RI)c photometry of 3C 273
- Short Name:
- J/MNRAS/392/1181
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The long baseline simultaneous multiband (BVRI) observations of blazar 3C 273 are presented. We have made 758 optical multiband observations with the Yunnan Astronomical Observatory (YAO) 103cm and Shanghai Astronomical Observatory (SHAO) 156cm from 2003 January to 2005 April. In our observational campaign, the average colour indices are B-V=0.21, V-R= 0.26 and R-I=0.31 . The mean magnitudes in B, V, R and I are 12.895, 12.698, 12.441 and 12.139, respectively. The source is in a steady state over observational campaign. The correlations between colour index and brightness are discussed. We find that the correlations of B-V versus B, V-R versus V and R-I versus R have significant negative correlation, while B-V versus V, V-R versus R and R-I versus I have positive correlation. These strong correlations imply that the spectrum becomes bluer (flatter) when the source becomes brighter, and redden (softer) when the source fades both in intraday and long-term variability. The spectral evolution trends of 3C 273 are consistent with those of BL Lac objects.
- ID:
- ivo://CDS.VizieR/J/AJ/132/111
- Title:
- BV(RI)_C_photometry of 77 Hyades stars
- Short Name:
- J/AJ/132/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New BV(RI)C observations of 77 stars in the Hyades are reported and discussed. The new observations are used to test published magnitudes and color indices for that cluster. For values of (V-R)C and (R-I)C published previously by Taylor & Joner (1985AJ.....90..479T and 2005, Cat. <J/ApJS/159/100>), the tests reveal no detectable scale-factor problems. In addition, the tests show that possible zero-point corrections to the published data can be no larger than a few millimagnitudes. These test results indicate that future studies requiring precision photometry for Hyades stars would be well served by selecting data samples from sources as close as possible to the native Cousins system. Tests of B-V photometry published by Johnson & Knuckles (1955ApJ...122..209J) reveal a zero-point ambiguity of approximately 8mmag in the new data that will require further measurements to resolve.
- ID:
- ivo://CDS.VizieR/J/A+AS/130/109
- Title:
- BV(RI)c photometry of ON 231
- Short Name:
- J/A+AS/130/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the most continuous data base of optical multiband data ever published on the BL Lacertae object ON 231 (W Com). The data have been collected during an intensive and coordinated BV(RI)c monitoring campaign carried out in the period from March 1994 to March 1997. During our campaign, the source brightness was at the highest level ever observed. The light curve shows a complex structure, characterized by the presence of three major outbursts having the observed maxima in March 1995, February 1996, and January 1997, when ON 231 reached its historical maximum (B~=14.2). Variability on time scales from a few hours up to a month have frequently been observed and the light curve seems to be the superposition of many flares with different amplitudes and time scales. The broad-band optical spectral energy distribution is characterized by a spectral slope which correlates with the flux level. In particular, the higher is the flux the flatter is the spectrum.
- ID:
- ivo://CDS.VizieR/J/A+A/395/11
- Title:
- BV(RI)c photometry of ON 231 during outburst
- Short Name:
- J/A+A/395/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the optical monitoring of the BL Lac object ON 231 from 1997 to the spring 2001, including the large outburst of spring 1998. After this event the mean source luminosity declined slowly and continued to show changes greater than one magnitude. A simple analysis of the variability time scales in the best-sampled segments of the light curve reveals that the luminosity changes were faster during the burst and slowed down in the subsequent years.
- ID:
- ivo://CDS.VizieR/J/A+A/327/61
- Title:
- BV(RI)c photometry of S5 0716+714
- Short Name:
- J/A+A/327/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 2 reports the journal of observations. For each date the measured magnitudes and their uncertainties in the four filters together with the used telescope are given. In some occasions several images were made in the course of the same night to search for intraday variability; these nights are indicated by an asterisk. The magnitude uncertainties have been evaluated by taking into account the mean dispersion of the internal error, but not the errors on the absolute calibration.
- ID:
- ivo://CDS.VizieR/J/A+A/451/435
- Title:
- BV(RI)c photometry of S5 0716+714
- Short Name:
- J/A+A/451/435
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We address the topic of the intra-night optical variability of the BL Lac object S5 0716+714. To this purpose a long-term observational campaign was carried out, from 1996 to 2003, which allowed the collection of a very large data set, containing 10675 photometric measurements obtained in 102 nights. The source brightness varied in a range of about 2mag, although the majority of the observations were performed when it was in the range 13.0<R<13.75. Variability time scales were estimated from the rates of magnitude variation, which were found to have a distribution function well fitted by an exponential law with a mean value of 0.027mag/h, corresponding to an e-folding time scale of the flux {tau}_F_=37.6h. The highest rates of magnitude variation were around 0.10-0.12mag/h and lasted less than 2h. These rates were observed only when the source had an R magnitude <13.4, but this finding cannot be considered significant because of the low statistical occurrence. The distribution of {tau}_F_ has a well-defined modal value at 19h. Assuming the recent estimate of the beaming factor {delta} about 20, we derived a typical size of the emitting region of about (5x10^16^)/(1+z)cm. The possibility of searching for a possible correlation between the mean magnitude variation rate and the long-term changes in the velocity of the superluminal components in the jet is discussed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/384/1675
- Title:
- BVRIc photometry of Stock 8
- Short Name:
- J/MNRAS/384/1675
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present UBVIc CCD photometry of the young open cluster Stock 8 with the aim of studying its basic properties such as the amount of interstellar extinction, distance, age, stellar contents and initial mass function (IMF). We also studied the star formation scenario in this region. From optical data, the radius of the cluster is found to be ~6arcmin (~3.6pc) and the reddening within the cluster region varies from E(B-V)=0.40 to 0.60mag. The cluster is located at a distance of 2.05+/-0.10kpc. Using H{alpha} slitless spectroscopy and Two Micron All Sky Survey (2MASS) near-infrared (NIR) data we identified H{alpha} emission and NIR-excess young stellar objects (YSOs), respectively.
- ID:
- ivo://CDS.VizieR/J/BaltA/14/41
- Title:
- BV(RI)C photometry of 4 S-type AGB
- Short Name:
- J/BaltA/14/41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present FCAPT differential Johnson BV and Cousins RI photometry and radial velocities of the S-type AGB stars RS Cnc, ST Her, OP Her and HR Peg. We performed multiperiodic analyses of this photometry to learn about the frequencies of variability. The B, V, R, and I light curves are generally in phase. RS Cnc has periods of order 122 and 248 days. Repeating the analyses using our data with the extensive V and R photometry of Percy et al. (2001PASP..113..983P) shows several periods near 248 days and a period near 135 days. The primary period of ST Her appears to be about 144 days although it is manifested most readily by its 103 day alias. OP Her and HR Peg exhibit periods, respectively, of about 416 and 116 days and of 54 and 74 days. The differences between our data set and the larger one of Percy et al. (2001PASP..113..983P) for RS Cnc raises important questions about multiperiodic analyses for AGB stars.
- ID:
- ivo://CDS.VizieR/J/A+A/370/503
- Title:
- BV(RI)c photometry of 7 symbiotic stars
- Short Name:
- J/A+A/370/503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- File table1.dat contains the UBV(RI)c magnitudes of the symbiotic stars AS 323, Ap 3-1, CM Aql, V1413 Aql, V443 Her, V627 Cas, V919 Sgr estimated on the Asiago archive plates. The date is given in the year/month/day format, and the magnitude is estimated in steps of 0.05mag
- ID:
- ivo://CDS.VizieR/J/AJ/141/115
- Title:
- BV(RI)c photometry on NGC 3532
- Short Name:
- J/AJ/141/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a deep, wide-field CCD survey for the open cluster NGC 3532. Our new BV(RI)c photometry effectively covers a one square degree area and reaches an unprecedented depth of V~21 to reveal that NGC 3532 is a rich open cluster that harbors a large number of faint, low-mass stars. We employ a number of methods to reduce the impact of field star contamination in the cluster color-magnitude diagrams (CMDs), including supplementing our photometry with JHKs data from the 2MASS catalog. These efforts allow us to define a robust sample of candidate main-sequence stars suitable for a purely empirical determination of the cluster's parameters by comparing them to the well-established Hyades main sequence.
- ID:
- ivo://CDS.VizieR/J/A+A/458/113
- Title:
- BVRIc photometry towards inner Galactic Bulge
- Short Name:
- J/A+A/458/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained BVRI photometry for 21 stellar fields located in directions towards the central 3.5{deg} of the Galaxy. Each field is 10x10 arcmin in size, and a total of ~2x10^5^ stars were measured.
- ID:
- ivo://CDS.VizieR/J/PASP/121/104
- Title:
- BVRI differential photometry of GW Gem
- Short Name:
- J/PASP/121/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New multiband CCD photometry is presented for the eclipsing binary GW Gem; the RI light curves are the first ever compiled. Four new minimum timings have been determined. Our analysis of eclipse timings observed during the past 79 years indicates a continuous period increase at a fractional rate of +(1.2+/-0.1)x10^10^, in excellent agreement with the value +1.1x10^-10^ calculated from the Wilson-Devinney binary code. The new light curves display an inverse O'Connell effect increasing toward longer wavelengths. Hot- and cool-spot models are developed to describe these variations but we prefer a cool spot on the secondary star. Our light-curve synthesis reveals that GW Gem is in a semidetached, but near-contact, configuration. It appears to consist of a near-main-sequence primary star with a spectral type of about A7 and an evolved early K-type secondary star that completely fills its inner Roche lobe. Mass transfer from the secondary to the primary component is responsible for the observed secular period change.
- ID:
- ivo://CDS.VizieR/J/AJ/149/30
- Title:
- BVRI differential photometry of V1001 Cas in 2012
- Short Name:
- J/AJ/149/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 2012 follow up to the analysis of 2009 observations is presented for the very short period (~0.43days) precontact W UMa binary (PCWB) V1001 Cassiopeia. Its short period, similar to the majority of W UMa binaries, and its distinct EA light curve make it a very rare and interesting system for continuing photometric investigation. Previous photometric VRI standard magnitudes give a K4 spectral type. Our solutions of light curves separated by some three years give approximately the same physical parameters. However, the spots have radically changed in temperature, area, and position. While only one dark spot was used to model the first curves, two hot spots are now needed. This affects the overall shape of the light curve, especially in the secondary eclipses in B and V. Additional eclipse timings now show that the orbital period is changing. We conclude that spots are very active on this solar-type dwarf system and that it may mimic its larger cousins, the RS CVn binaries. The conclusion is that analysis now needs to be directed at the continuous time evolution of PCWBs.
- ID:
- ivo://CDS.VizieR/J/A+A/384/890
- Title:
- BVRIHalpha photometry of NGC 2244 X-ray stars
- Short Name:
- J/A+A/384/890
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high spatial resolution optical photometry of NGC 2244 in the Rosette Nebula using the NOAO MOSAIC Imager at Kitt Peak. We obtained BVIR and H{alpha} images of the central cluster and surrounding nebulae, and present results for 138 sources selected from X-ray observations with the ROSAT PSPC and HRI. Color-magnitude diagrams of the cluster show a large number of the stars are still undergoing contraction onto the main sequence. The faintest X-ray selected cluster members have the highest X-ray-to-optical luminosities (L_x_~>7x10^30^erg/s; L_x_/L_bol_=~10^-2^ to 10^-3^) and indicate they are a population of young active late-type stars. H{alpha} emission from the X-ray emitters is also remarkable. We have extended the detections of PMS stars in NGC 2244 well into the ran ge of K spectral types. While most of the cluster stars are located in the color-magnitude diagrams in between the ZAMS and the 3Myrs isochrone, significantly younger low mass stars exist and confirm earlier reports that star formation is still going on in the Rosette Nebula/NGC 2244 region.
- ID:
- ivo://CDS.VizieR/J/A+AS/141/103
- Title:
- BVRI imaging of M 51-type pairs
- Short Name:
- J/A+AS/141/103
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present decompositions of azimuthally averaged surface brightness profiles in optical B, V, R and I-bands for a sample of 40 M 51-type interacting galaxies. The profiles were modelled by an exponential disk and a spherical bulge described either by the R^1/4^ law or by an exponential function. Half of the galaxies were well fitted by both bulge models, whereas for 35% the exponential function was a better choice. Special care was taken on eliminating superpositions of the companion galaxies. The mean B-band central surface brightness {mu}_0_was found to be 21.5mag/arcsec^2^, which is near to the value originally found by Freeman (1970ApJ...160..811F), but the scatter was fairly large. Galaxy interactions have strongly modified the disks in many of the galaxies in the sample. For example, six of them had extremely flat brightness profiles outside the exponential part of the disk, and many showed significant isophotal twists.
- ID:
- ivo://CDS.VizieR/J/A+A/451/1159
- Title:
- BVRI imaging of the Coma cluster
- Short Name:
- J/A+A/451/1159
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained deep and wide field imaging of the Coma cluster of galaxies with the CFH12K camera at CFHT in the B, V, R and I filters. In this paper, we present the observations, data reduction, catalogs and first scientific results. We investigated the quality of our data by internal and external literature comparisons. We also checked the realisation of the observational requirements we set. Images are available at http://cencosw.oamp.fr
- ID:
- ivo://CDS.VizieR/J/A+A/462/1081
- Title:
- BVRIJHK light curves of 4U 0115+63/V635 Cas
- Short Name:
- J/A+A/462/1081
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 4U 0115+63 is one of the most active and best studied Be/X-ray transients. Previous studies of 4U 0115+63 have led to the suggestion that 4U 0115+63 undergoes relatively fast quasi-cyclic activity. However, due to the lack of good coverage of the observations, the variability time scales are uncertain. Our objective is to investigate the long-term behaviour of 4U 0115+63/V635 Cas to confirm its quasi-cyclic nature and to explain its correlated optical/IR and X-ray variability. We have performed optical/IR photometric observations and optical spectroscopic observations of 4U 0115+63/V635 Cas over the last decade with unprecedented coverage. We have focused on the H{alpha} line variability and the long-term changes of the photometric magnitudes and colours and investigated these changes in correlation with the X-ray activity of the source.
- ID:
- ivo://CDS.VizieR/J/ApJS/133/413
- Title:
- BVRIJHK photometry of cool white dwarfs
- Short Name:
- J/ApJS/133/413
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed photometric and spectroscopic analysis of cool (T_eff_<~12000K) white dwarf stars is presented. The sample has been drawn from the Yale Parallax Catalog and from a proper motion survey in the southern hemisphere. Optical BVRI and infrared JHK photometry, as well as spectroscopy at H{alpha}, have been secured for a sample of 152 white dwarfs. The discovery of seven new DA white dwarfs, two new DQ white dwarfs, one new magnetic white dwarf, and three weak magnetic white dwarf candidates, is reported. Our sample also identifies 19 known or suspected double degenerates.
- ID:
- ivo://CDS.VizieR/J/A+A/385/884
- Title:
- BVRIJHK photometry of 27 post-AGB candidates
- Short Name:
- J/A+A/385/884
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRIJHK photometric observations are presented for 27 post-AGB candidates. Almost all objects show a double peaked spatial energy distribution (SED) curve in the optical to far-infrared wavelengths. Seventeen objects were classified as post-AGB stars on the basis of their spectral type, location in the IRAS color-color diagram and SED. The physical parameters of the observed post-AGB stars, the inner radius of the detached shell, the mass of the shell and the distance were derived using the simple dust shell model. We compared our observational sequence of post-AGB objects to the theoretical evolutionary sequence (Schoenberner, 1983ApJ...272..708S; Bloecker, 1995, Cat. <J/A+A/299/755>) in the stellar temperatures versus age diagram. We found that two post-AGB stars, IRAS 05040+4820 and 08187-1905, have low stellar temperature with a large dynamical age of the dust shell. They appear to provide the first observational evidence that some low-mass stars bypass the planetary nebulae stage because of their slow increase in stellar temperature.
- ID:
- ivo://CDS.VizieR/J/MNRAS/289/729
- Title:
- BVRIJHK photometry of red LMC supergiants
- Short Name:
- J/MNRAS/289/729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (BV)_J_(RI)_C_ observations for 185 and additional JHK observations for 53 red supergiant candidates in the Large Magellanic Cloud (LMC) are presented. The data have been reduced discussing carefully the dependence of effective wavelengths on the spectral energy distribution of the star, which is very strong especially for the Cousins R band. Non-linear colour dependences of transformation coefficients vor the V magnitude and the R-I colour have been taken into account. The mean error of the BVRI data is 0.03 to 0.04 mag, while that of the JHK observations is 0.02mag. The MK types are not given to the stars, as the classifications given in the literature are mostly very uncertain. The spectra we have obtained for 88 of the stars will be discussed in a forthcoming paper where we will give directly physical properties like Mbol and Teff instead of MK types. Most of the stars are supergiants of type late K to early M.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/118
- Title:
- BVRIJHK photometry of the 2008 OT in NGC 300
- Short Name:
- J/ApJ/743/118
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 2008 optical transient in NGC 300 is one of a growing class of intermediate-luminosity transients that brighten several orders of magnitude from a previously optically obscured state. The origin of their eruptions is not understood. Our multi-wavelength photometry and spectroscopy from maximum light to more than a year later provide a record of its post-eruption behavior. We describe its changing spectral energy distribution, the evolution of its absorption- and emission-line spectrum, the development of a bipolar outflow, and the rapid transition from a dense wind to an optically thin ionized wind. In addition to strong, narrow hydrogen lines, the F-type absorption-line spectrum of the transient is characterized by strong CAII and [CAII] emission. The very broad wings of the CAII triplet and the asymmetric [CAII] emission lines are due to strong Thomson scattering in the expanding ejecta. Post-maximum, the hydrogen and CaII lines developed double-peaked emission profiles that we attribute to a bipolar outflow. Between approximately 60 and 100 days after maximum, the F-type absorption spectrum, formed in its dense wind, weakened and the wind became transparent to ionizing radiation. We discuss the probable evolutionary state of the transient and similar objects such as SN 2008S and conclude that they were most likely post-red supergiants or post-asymptotic giant branch stars on a blue loop to warmer temperatures when the eruption occurred. These objects are not luminous blue variables.
- ID:
- ivo://CDS.VizieR/J/AJ/128/2316
- Title:
- BVRIJHKs photometry in sigma Ori cluster
- Short Name:
- J/AJ/128/2316
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report an optical photometric survey of 0.89deg^2^ of the Orion OB1b association centered on sigma Ori. This region includes most of the sigma Ori cluster, the highest-density region within Orion OB1b. We have developed a statistical procedure to identify the young, low-mass, pre-main-sequence population of the association. We estimate that the cluster has 160 members in the mass range (0.2M_{sun}_<=M<=1.0M_{sun}_). The cluster has a radius of 35pc and an estimated age of 2.5+/-0.3Myr. We estimate that the total mass of the cluster is 225+/-30M_{sun}_. This mass is similar to the estimated mass of the ~5x10^5^yr old cluster NGC 2024. NGC 2024 and sigma Ori appear to be a well-matched pair of clusters, except for the ~2Myr difference in their ages.
- ID:
- ivo://CDS.VizieR/J/A+A/415/521
- Title:
- BVRIJK and velocities for MC Cepheids
- Short Name:
- J/A+A/415/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high precision and well sampled BVRIJK light curves and radial velocity curves for a sample of five (+1) Cepheids in the SMC. In addition we present radial velocity curves for five (+1) Cepheids in the LMC. The low metallicity ([Fe/H]~-0.7) SMC stars have been selected for use in a Baade-Wesselink type analysis to constrain the metallicity effect on the Cepheid Period-Luminosity relation. The stars have periods of around 15 days so they are similar to the Cepheids observed by the Extragalactic Distance Scale Key Project on the Hubble Space Telescope. We show that the stars are representative of the SMC Cepheid population at that period and thus will provide a good sample for the proposed analysis. The actual Baade-Wesselink analysis are presented in Strom et al., 2004, Cat. <J/A+A/415/531>.
- ID:
- ivo://CDS.VizieR/J/A+A/416/1037
- Title:
- BVRIK Photometry for the field of 4U 0142+61
- Short Name:
- J/A+A/416/1037
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new optical and infrared observations of the counterpart to the Anomalous X-ray Pulsar (AXP) 4U 0142+61 taken with the Keck I telescope. The counterpart is found to be variable in the infrared. This contrasts with our optical observations, which do not show any evidence for variability. Apart from the variability the AXP shows a remarkable spectral energy distribution. In particular, we find a sudden drop in flux going from V to B, presumably due to a spectral feature. We compare our results to those obtained for the two other securely identified AXP counterparts, to 1E 2259+586 and 1E 1048.1-5937. 4U 0142+61 is very similar to the former source in its X-ray timing and spectral properties, and we find that this similarity extends to the quiescent infrared to X-ray flux ratio. For 1E 1048.1-5937, which has different X-ray properties, the situation is less clear: in one observation, the infrared to X-ray flux ratio was much larger, but another observation gave an upper limit which is consistent with that observed for 4U 0142+61. Assuming the quiescent ratios are all similar, we estimate the optical and infrared brightnesses for the three AXPs that remain to be identified as well as for the four Soft Gamma-ray Repeaters. We also discuss briefly how the observed optical and infrared emission might arise, in particular in the context of the magnetar model.
- ID:
- ivo://CDS.VizieR/J/ApJ/825/L22
- Title:
- BVRI LCs of type Ib supernova iPTF13bvn
- Short Name:
- J/ApJ/825/L22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Supernova (SN) iPTF13bvn in NGC 5806 was the first Type Ib SN to have been tentatively associated with a progenitor in pre-explosion images. We performed deep ultraviolet (UV) and optical Hubble Space Telescope observations of the SN site ~740 days after explosion. We detect an object in the optical bands that is fainter than the pre-explosion object. This dimming is likely not produced by dust absorption in the ejecta; thus, our finding confirms the connection of the progenitor candidate with the SN. The object in our data is likely dominated by the fading SN, implying that the pre-SN flux is mostly due to the progenitor. We compare our revised pre-SN photometry with previously proposed models. Although binary progenitors are favored, models need to be refined. In particular, to comply with our deep UV detection limit, any companion star must be less luminous than a late-O star or substantially obscured by newly formed dust. A definitive progenitor characterization will require further observations to disentangle the contribution of a much fainter SN and its environment.
- ID:
- ivo://CDS.VizieR/J/AJ/161/193
- Title:
- BVRI light curve of RR Lyrea V* AX UMa
- Short Name:
- J/AJ/161/193
- Date:
- 10 Dec 2021
- Publisher:
- CDS
- Description:
- The pulsation periods of RR-Lyrae stars usually vary with time, and they are often used as probes to study the mechanism behind the variation. After the early discovery that the pulsation period of the RR-Lyrae star AXUMa decreased rapidly, in further research, we made multiband photometric observations of this star using the Sino-Thai 70cm telescope and the 60cm telescope at Yunnan Observatories, and collected its light-curve data from several photometry sky surveys. The O-C diagram confirmed that AX UMa has a rapid period decrease with a rate of -7.752{+/-}0.005days/Myr, which indicates that it is the fastest-period decreasing ab-type RR Lyrae star in the Galactic field. Moreover, the O-C residuals contain additional periodic variations. We suppose that the variation with a long period is probably caused by the light-travel time effect as the star orbits in a binary system. The calculation shows that the lower mass limit of the companion is about 1M{sun}. Combined with the full amplitudes and color indexes, we suggested that the companion is probably a hot subdwarf star. We compared the light curves of AXUMa and those of another binary evolution pulsator, OGLE-BLG-RRLYR-02792, and found that the former shows the characteristics of ab-type RR-Lyrae stars, while the latter is more like an extreme long-period c-type RR-Lyrae star. However, the absence of a bump in the light curves implies that the mass loss has occurred in the outer atmosphere of AXUMa. The special features of AXUMa make it worth more attention and further observations.
- ID:
- ivo://CDS.VizieR/J/A+A/542/A78
- Title:
- BVRI light curves and RV curves of 65 UMa
- Short Name:
- J/A+A/542/A78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The study of stellar multiple systems provides us with important information about the stellar formation processes and can help us to estimate the multiplicity fraction in the Galaxy. 65 UMa belongs to a rather small group of stellar systems of higher multiplicity, whose inner and outer orbits are well-known. This allows us to study the long-term stability and evolution of the orbits in these systems. We obtained new photometric and spectroscopic data that when combined with interferometric data enables us to analyze the system 65 UMa and determine its basic physical properties.
- ID:
- ivo://CDS.VizieR/J/A+A/539/A129
- Title:
- BVRI light curves of 3 eclipsing binaries
- Short Name:
- J/A+A/539/A129
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to derive the absolute parameters of the components of AD And, AL Cam, and V338 Her, interpret their orbital period changes and discuss their evolutionary status. New and complete multi-filter light curves of the eclipsing binaries AD And, AL Cam, and V338 Her were obtained and analysed with modern methods. Using all reliably observed times of minimum light, we examined orbital period irregularities using the least squares method. In addition, we acquired new spectroscopic observations during the secondary eclipses for AL Cam and V338 Her. For AL Cam and V338 Her, we derive reliable spectral types for their primary stars. Statistical checks of orbital period analysis for all systems are very reassuring in the cases of V338 Her and AD And, although less so for AL Cam. The LIght-Time Effect (LITE) results are checked by inclusion of a third light option in the photometric analyses. Light curve solutions provide the means to calculate the absolute parameters of the components of the systems and reliably estimate their present evolutionary status. AL Cam and V338 Her are confirmed as classical Algols of relatively low mass in similar configurations. Unlike AL Cam, however, V338 Her is still transferring matter between its components, raising interest in the determinability of the evolutionary histories of Algols. AD And is found to be a detached system in which both close stars are of age 10^9^yr and is probably a "non-classical" young triple, at an interesting stage of its dynamical evolution.
- ID:
- ivo://CDS.VizieR/J/A+A/493/1093
- Title:
- BVRI light curves of {eta} Car
- Short Name:
- J/A+A/493/1093
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The periodicity of 5.5 years for some observational events occurring in {eta} Carinae manifests itself across a large wavelength range and has been associated with its binary nature. These events are supposed to occur when the binary components are close to periastron. To detect the previous periastron passage of {eta} Car in 2003, we started an intensive, ground-based, optical, photometric observing campaign. We continued observing the object to monitor its photometric behavior and variability across the entire orbital cycle. Our observation program consisted of daily differential photometry from CCD images, which were acquired using a 0.8m telescope and a standard BVRI filter set at La Plata Observatory. The photometry includes the central object and the surrounding Homunculus nebula. We present up-to-date results of our observing program, including homogeneous photometric data collected between 2003 and 2008. Our observations demonstrated that {eta} Car has continued increasing in brightness at a constant rate since 1998. In 2006, it reached its brightest magnitude (V~4.7) since about 1860s. The object then suddenly reverted its brightening trend, fading to V=5.0 at the beginning of 2007, and has maintained a quite steady state since then. We continue the photometric monitoring of {eta} Car in anticipation of the next "periastron passage", predicted to occur at the beginning of 2009.
- ID:
- ivo://CDS.VizieR/J/other/NewA/53.39
- Title:
- BVRI light curves of GR Boo
- Short Name:
- J/other/NewA/53.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present BVRI light curves with complete phase coverage for the short-period (p=0.377day) eclipsing binary star GR Boo. We carried out the observations using the SARA 90cm telescope located at Kitt Peak National Observatory. We obtained six new light curve minimum times. By fitting all of the available O-C minimum times, we obtained an updated ephemeris that shows the orbital period of GR Boo is decreasing at a rate of dP/dt=-2.36x10^-7^days/year. This decrease in its period can be explained by either mass transfer from the more massive component to the less massive one, or angular momentum exchange due to magnetic activities. We also obtained a set of revised orbital parameters using the Wilson & Devinney program. And finally, we concluded that GR Boo is a contact binary with a dark spot.
- ID:
- ivo://CDS.VizieR/J/MNRAS/406/2559
- Title:
- BVRI light curves of GSC2314-0530
- Short Name:
- J/MNRAS/406/2559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CD photometric observations in VRI colours and spectroscopic observations of the newly discovered eclipsing binary GSC 2314-0530 (NSVS 6550671) with dMe components and a very short period of P=0.192636d are presented. The simultaneous light-curve solution and radial velocity solution allow us to determine the global parameters of GSC 2314-0530: T1=3735K; T2=3106K; M1=0.51M_{sun}_; M2=0.26M_{sun}_; R1=0.55R_{sun}_; R2=0.29R_{sun}_; L1=0.053L_{sun}_; L2=0.007L_{sun}_; i=72.5{swg}; a=1.28R_{sun}_; d=59pc.
- ID:
- ivo://CDS.VizieR/J/MNRAS/433/394
- Title:
- BVRI light curves of KIC 6382916
- Short Name:
- J/MNRAS/433/394
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a multisite photometric campaign on the high-amplitude {delta} Scuti star KIC 6382916 in the Kepler field. The star was observed over a 85-d interval at five different sites in North America and Europe during 2011. Kepler photometry and ground-based multicolour light curves of KIC 6382916 are used to investigate the pulsational content and to identify the principal modes. High-dispersion spectroscopy was also obtained in order to derive the stellar parameters and projected rotational velocity. From an analysis of the Kepler time series, three independent frequencies and a few hundred combination frequencies are found. The light curve is dominated by two modes with frequencies f1=4.9107d^-1^ and f2=6.4314d^-1^. The third mode with f3=8.0350d^-1^ has a much lower amplitude. We attempt mode identification by examining the amplitude ratios and phase differences in different wavebands from multicolour photometry and comparing them to calculations for different spherical harmonic degree, l. We find that the theoretical models for f1 and f2 are in a best agreement with the observations and lead to value of l=1 modes, but the mode identification of f3 is uncertain due to its low amplitude. Non-adiabatic pulsation models show that frequencies below 6d^-1^ are stable, which means that the low frequency of f1 cannot be reproduced. This is a further confirmation that current models predict a narrower pulsation frequency range than actually observed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/413/2709
- Title:
- BVRI light curves of KIC Cepheids
- Short Name:
- J/MNRAS/413/2709
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report results of initial work done on selected candidate Cepheids to be observed with the Kepler space telescope. Prior to the launch, 40 candidates were selected from previous surveys and data bases. The analysis of the first 322d of Kepler photometry, and recent ground-based follow-up multicolour photometry and spectroscopy allowed us to confirm that one of these stars, V1154 Cyg (KIC 7548061), is indeed a 4.9d Cepheid. Using the phase lag method, we show that this star pulsates in the fundamental mode. New radial velocity data are consistent with previous measurements, suggesting that a long-period binary component is unlikely. No evidence is seen in the ultraprecise, nearly uninterrupted Kepler photometry for non-radial or stochastically excited modes at the micromagnitude level. The other candidates are not Cepheids, but an interesting mix of possible spotted stars, eclipsing systems and flare stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/407/497
- Title:
- BVRI light curves of KZ Pav
- Short Name:
- J/MNRAS/407/497
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from analysing new spectroscopic and photometric observations of the KZ Pav (IDS 20490-7048 A-BC) multiple system. High-resolution spectra were taken at the Mt John University Observatory in 2007 and 2008. Radial velocities for the close binary were determined from cross-correlation and spectral disentangling methods.
- ID:
- ivo://CDS.VizieR/J/A+A/601/A133
- Title:
- BVRI light curves of 3 massive binaries
- Short Name:
- J/A+A/601/A133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The role of mass and momentum exchanges in close massive binaries is very important in the subsequent evolution of the components. Such exchanges produce several observational signatures such as asynchronous rotation and altered chemical compositions, that remain after the stars detach again. We investigated these effects for the close O-star binary LSS 3074 (O4f+O6-7:(f):), which is a good candidate for a past Roche lobe overflow (RLOF) episode because of its very short orbital period, P=2.185-days, and the luminosity classes of both components. We determined a new orbital solution for the system. We studied the photometric light curves to determine the inclination of the orbit and Roche lobe filling factors of both stars. Using phase-resolved spectroscopy, we performed the disentangling of the optical spectra of the two stars. We then analysed the reconstructed primary and secondary spectra with the CMFGEN model atmosphere code to determine stellar parameters, such as the effective temperatures and surface gravities, and to constrain the chemical composition of the components. We confirm the apparent low stellar masses and radii reported in previous studies. We also find a strong overabundance in nitrogen and a strong carbon and oxygen depletion in both primary and secondary atmospheres, together with a strong enrichment in helium of the primary star. We propose several possible evolutionary pathways through a RLOF process to explain the current parameters of the system. We confirm that the system is apparently in overcontact configuration and has lost a significant portion of its mass to its surroundings. We suggest that some of the discrepancies between the spectroscopic and photometric properties of LSS 3074 could stem from the impact of a strong radiation pressure of the primary.
- ID:
- ivo://CDS.VizieR/J/ApJ/694/1237
- Title:
- BVRI light curves of NGC 247 Cepheids
- Short Name:
- J/ApJ/694/1237
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report VRI CCD observations of nine Cepheids in the South Polar (Sculptor) Group spiral galaxy NGC 0247. Periods of these Cepheids range from 20 to 70 days. Over the past 20 years, the brightest Cepheid in our sample, NGC 0247:[MF09] C1, has decreased its period by 6%, faded by 0.8mag in the V band, and become bluer by 0.23mag in (V-I).
- ID:
- ivo://CDS.VizieR/J/MNRAS/454/123
- Title:
- BVRI light curves of Nova V723 Cas
- Short Name:
- J/MNRAS/454/123
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical spectroscopy collected at seven epochs and BVRcIc photometry obtained at 1227 epochs of nova V723 Cas, covering the time interval between 2007 and 2015. The mean magnitude during this period, stable at ~3mag brighter than in quiescence, and the continuous presence of strong [FeX] and other high-ionization emission lines, indicates that the nuclear burning at the surface of the white dwarf is continuing 20-years past the initial outburst. The light curve shows a large amplitude (2mag) orbital modulation, which is governed by the visibility of the irradiated side of the secondary star. Our observations do not confirm the reported increase with time of the orbital period of V723 Cas, a period of P=16.638383+/-0.000025h satisfying equally well all available observations in all bands. Our observations also do not confirm the presence of an additional periodicity around P=15.2397h from which V723 Cas was classified as an intermediate-polar system.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A137
- Title:
- BVRI light curves of PG 1553+113
- Short Name:
- J/A+A/645/A137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The TeV BL Lac object PG 1553+113 is one of the primary candidates for a binary supermassive black hole system. We study the flux and spectral variability of PG 1553+113 on intra-night to long-term timescales using (i) BVRI data collected over 76 nights from January 2016 to August 2019 involving nine optical telescopes and (ii) historical VR data (including ours) obtained for the period from 2005 to 2019. We analysed the light curves using various statistical tests, fitting and cross-correlation techniques, and methods for the search for periodicity. We examined the colour-magnitude diagrams before and after the corresponding light curves were corrected for the long-term variations. Our intra-night monitoring, supplemented with literature data, result in a low duty cycle of ~(10-17)%. In April 2019, we recorded a flare, which marks the brightest state of PG 1553+113 for the period from 2005 to 2019: R~13.2mag. This flare is found to show a clockwise spectral hysteresis loop on its VR colour-magnitude diagram and a time lag in the sense that the V-band variations lead the R-band ones. We obtain estimates of the radius, the magnetic field strength, and the electron energy that characterize the emission region related to the flare. We find a median period of (2.21+/-0.04) years using the historical light curves. In addition, we detect a secondary period of about 210 days using the historical light curves corrected for the long-term variations. We briefly discuss the possible origin of this period.
- ID:
- ivo://CDS.VizieR/J/AJ/136/1846
- Title:
- BVRI light curves of S5 0716+714
- Short Name:
- J/AJ/136/1846
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the optical photometry (B, V, R, and I) of the BL Lac object S5 0716+714 (z>0.3), which were observed with the 1m telescope at Yunnan Astronomical Observatory and the 1.56m telescope at Shanghai Astronomical Observatory from 2001 February to 2006 April.
- ID:
- ivo://CDS.VizieR/J/other/NewA/20.30
- Title:
- BVRI light curves of 3 SN
- Short Name:
- J/other/NewA/20.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate and densely populated BVRcIc lightcurves of supernovae SN 2011fe in M101, SN 2012aw in M95 and SN 2012cg in NGC 4424 are presented and discussed. The SN 2011fe lightcurves span a total range of 342 days, from 17 days pre- to 325 days post-maximum. The observations of both SN 2012aw and SN 2012cg were stopped by solar conjunction, when the objects were still bright. The lightcurve for SN 2012aw covers 92 days, that of SN 2012cg spans 44 days. Time and brightness of maxima are measured, and from the lightcurve shapes and decline rates the absolute magnitudes are obtained, and the derived distances are compared to that of the parent galaxies. The color evolution and the bolometric lightcurves are evaluated in comparison with those of other well observed supernovae, showing no significant deviations.
- ID:
- ivo://CDS.VizieR/J/PASP/122/1
- Title:
- BVRI light curves of SN 2007gi
- Short Name:
- J/PASP/122/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical photometry and spectra for the Type Ia supernova (SN Ia) 2007gi in the nearby galaxy NGC 4036. SN 2007gi is characterized by extremely high-velocity (HV) features of the intermediate-mass elements (Si, Ca, and S), with expansion velocities (v_exp_) approaching 15500km/s near-maximum brightness (compared to 10600km/s for SNe Ia with normal v_exp_). SN 2007gi reached a B-band peak magnitude of 13.25+/-0.04mag with a decline rate of {DELTA}m15(B)(true)=1.33+/-0.09mag. The B-band light curve of SN 2007gi demonstrated an interesting two-stage evolution during the nebular phase, with a decay rate of 1.16+/-0.05mag/(100days) during t=60-90days and 1.61+/-0.04mag/(100days) thereafter. Such behavior was also observed in the HV SN Ia 2006X, and might be caused by the interaction between supernova ejecta and circumstellar material (CSM) around HV SNe Ia. Based on a sample of a dozen well-observed R band (or unfiltered) light curves of SNe Ia, we confirm that the HV events may have a faster rise time to maximum than those with normal v_exp_.
- ID:
- ivo://CDS.VizieR/J/AJ/145/99
- Title:
- BVRI light curves of SN 2003ie
- Short Name:
- J/AJ/145/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new photometric observations of supernova (SN) 2003ie starting one month before discovery, obtained serendipitously while observing its host galaxy. With only a weak upper limit derived on the mass of its progenitor (<25M_{sun}_) from previous pre-explosion studies, this event could be a potential exception to the "red supergiant (RSG) problem" (the lack of high-mass RSGs exploding as Type IIP SNe). However, this is true only if SN2003ie was a Type IIP event, something which has never been determined. Using recently derived core-collapse SN light-curve templates, as well as by comparison to other known SNe, we find that SN2003ie was indeed a likely Type IIP event. However, with a plateau magnitude of ~-15.5mag, it is found to be a member of the faint Type IIP class. Previous members of this class have been shown to arise from relatively low-mass progenitors (<12M_{sun}_). It therefore seems unlikely that this SN had a massive RSG progenitor. The use of core-collapse SN light-curve templates is shown to be helpful in classifying SNe with sparse coverage. These templates are likely to become more robust as large homogeneous samples of core-collapse events are collected.
- ID:
- ivo://CDS.VizieR/J/MNRAS/383/1485
- Title:
- BVRI light curves of SN 2003jd
- Short Name:
- J/MNRAS/383/1485
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a worldwide coordinated observational campaign on the broad-lined Type Ic supernova (SN Ic) 2003jd are presented. In total, 74 photometric data points and 26 spectra were collected using 11 different telescopes. SN 2003jd is one of the most luminous SN Ic ever observed. A comparison with other Type Ic supernovae (SNe Ic) confirms that SN 2003jd represents an intermediate case between broad-line events (2002ap, 2006aj) and highly energetic SNe (1997ef, 1998bw, 2003dh, 2003lw), with an ejected mass of M_ej_=3.0+/-1M_{sun}_ and a kinetic energy of E_k_(tot)=7^+3^_-2_x10^51^erg. SN 2003jd is similar to SN 1998bw in terms of overall luminosity, but it is closer to SNe 2006aj and 2002ap in terms of light-curve shape and spectral evolution. The comparison with other SNe Ic suggests that the V-band light curves of SNe Ic can be partially homogenized by introducing a time-stretch factor. Finally, because of the similarity of SN 2003jd to the SN 2006aj/XRF 060218 event, we discuss the possible connection of SN 2003jd with a gamma-ray burst (GRB).
- ID:
- ivo://CDS.VizieR/J/AJ/157/3
- Title:
- BVRI light curves of the binary QS Vir
- Short Name:
- J/AJ/157/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed the post-common-envelope eclipsing binary with a white dwarf component, QS Vir, using the 1.88 m telescope of Kotammia Observatory in Egypt. The new observations were analyzed together with all multicolor light curves available online (sampling a period of 25 yr), using a full-feature binary system modeling software based on Roche geometry. This is the first time complete photometric modeling was done with most of these data. QS Vir is a detached system, with the red dwarf component underfilling its Roche lobe by a small margin. All light curves feature out-of-eclipse variability that is associated with ellipsoidal variation, mutual irradiation and irregularities in surface brightness of the tidally distorted and magnetically active red dwarf. We tested models with one, two, and three dark spots and found that one spot is sufficient to account for the light curve asymmetry in all data sets, although this does not rule out the presence of multiple spots. We also found that a single spotted model cannot fit light curves observed simultaneously in different filters. Instead, each filter requires a different spot configuration. To thoroughly explore the parameter space of spot locations, we devised a grid-search procedure and used it to find consistent solutions. Based on this, we conclude that the dark spot responsible for light curve distortions has been stable for the past 15 yr, after a major migration that happened between 1993 and 2002, possibly due to a flip-flop event.
- ID:
- ivo://CDS.VizieR/J/ApJ/849/161
- Title:
- BVRI light curves of the BL Lac object Mrk 501
- Short Name:
- J/ApJ/849/161
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present our observations of the optical intra-day variability (IDV) in {gamma}-ray BL Lac object Mrk 501. The observations were run with the 1.02m and 2.4m optical telescopes at Yunnan Observatories from 2005 April to 2012 May. The light curve at the R band on 2010 May 15 passes both variability tests (the F-test and the ANOVA test). A flare within the light curve on 2010 May 15 has a magnitude change of {Delta}m=0.03+/-0.005_stat_+/-0.007_sys_mag, a darkening timescale of {tau}_d_=26.7min., and an amplitude of IDV Amp=2.9%+/-0.7% . A decline described by 11 consecutive flux measurements within the flare can be fitted linearly with a Pearson's correlation coefficient r=0.945 at the confidence level of >99.99% . Under the assumptions that the IDV is tightly connected to the mass of the black hole, and that the flare duration, being two times {tau}_d_, is representative of the minimum characteristic timescale, we can derive upper bounds to the mass of the black hole. In the case of the Kerr black hole, the timescale of {Delta}t_min_^ob^=0.89hr gives M_{bullet}_<~10^9.20^M_{sun}_, which is consistent with measurements reported in the literature. This agreement indicates that the hypothesis about M_{bullet}_ and {Delta}t_min_^ob^ is consistent with the measurements/data.
- ID:
- ivo://CDS.VizieR/J/AJ/145/9
- Title:
- BVRI light curves of the early-type binary V382 Cyg
- Short Name:
- J/AJ/145/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze photometric and spectroscopic data and study the orbital period of the early-type interacting binary system V382 Cyg by using all the available data. We obtain a simultaneous light and radial velocity curve solution. The derived physical parameters of the primary and secondary stellar components are M_1_=27.9(5)M_{sun}_, M_2_=20.8(4)M_{sun}_, R_1_=9.7(2)R_{sun}_, R_2_=8.5(2)R_{sun}_, log(L_1_/L_{sun}_)=5.152(20), and log(L_2_/L_{sun}_)=4.954(19) while the separation of the components is a=23.4R_{sun}_. Newly obtained parameters yield the distance of the system to be 1466(76)pc. Analyses of the mid-eclipse times indicate a period increase of dP/dt=4.2(1)x10^-7^days/yr that can be interpreted in terms of the high-mass transfer (dM/dt=6.1(5)x10^-6^M_{sun}_/yr) from the less massive component to the more massive component. Finally, we model the evolution of the components using non-conservative codes and discuss the results obtained. The age of the binary system is estimated to be 3.85Myr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/442/844
- Title:
- BVRI light curves of type II-P supernovae
- Short Name:
- J/MNRAS/442/844
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a sample of 23 Type II plateau supernovae (SNe II-P), all observed with the same set of instruments. Analysis of their photometric evolution confirms that their typical plateau duration is 100 d with little scatter, showing a tendency to get shorter for more energetic SNe. We examine the claimed correlation between the luminosity and the rise time from explosion to plateau. We analyse their spectra, measuring typical ejecta velocities, and confirm that they follow a well-behaved power-law decline. We find indications of high-velocity material in the spectra of six of our SNe. We test different dust-extinction correction methods by asking the following - does the uniformity of the sample increase after the application of a given method? A reasonably behaved underlying distribution should become tighter after correction. No method we tested made a significant improvement.
- ID:
- ivo://CDS.VizieR/J/AJ/133/2696
- Title:
- BVRI light curves of Westerlund 1 stars
- Short Name:
- J/AJ/133/2696
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the first optical variability study of the Westerlund 1 super star cluster in search of massive eclipsing binary systems. A total of 129 new variable stars have been identified, including the discovery of 4 eclipsing binaries that are cluster members, 1 additional candidate, 8 field binaries, 19 field delta Scuti stars, 3 field W UMa eclipsing binaries, 13 other periodic variables, and 81 long-period or nonperiodic variables. These include the known luminous blue variable, the B[e] star, 11 Wolf-Rayet stars, several supergiants, and other reddened stars that are likely members of Westerlund 1. The bright X-ray source corresponding to the Wolf-Rayet star WR 77o (B) is found to be a 3.51 day eclipsing binary. The discovery of a reddened detached eclipsing binary system implies the first identification of main-sequence stars in Westerlund 1.
- ID:
- ivo://CDS.VizieR/J/AJ/149/48
- Title:
- BVRI light curves of ZZ Eri
- Short Name:
- J/AJ/149/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Complete Bessel BVRI light curves of ZZ Eri [2MASSJ04130109-1044545, HV 6280, NSVS 14888164; IRCS position 04:13:01.10-10:44:54.5; V=13.9-14.4-15.0] are observed and analyzed. The system is a southern pre-contact W UMa binary. Its light curve has the appearance of an Algol (EA) light curve, however, it is made up of dwarf solar-type components with a period of only 0.4521days. Our 34year period study yields a sinusoidal fit or an increasing quadratic fit. The sinusoid may indicate that a third body is orbiting the close binary. The lower-limit mass of the third body is near that of the brown dwarf limit (0.095M_{sun}_). Also included is an improved ephemeris, a mass ratio search, and a simultaneous BVRI Wilson-Devinney solution.
- ID:
- ivo://CDS.VizieR/J/ApJS/218/18
- Title:
- 2004-2012 BVRI observations of blazar S5 0716+714
- Short Name:
- J/ApJS/218/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present long-term optical multi-band photometric monitoring of blazar S5 0716+714, from 2004 January 11 to 2012 November 4, with high temporal resolution of approximately 15 minutes in the BVRI bands. The source was in an active state during the whole monitoring campaign, showing intraday variability in 11 of 72 days. The average magnitudes in each band were B=14.398, V=13.821, R=13.255, and I=12.885. The overall variability amplitudes were {Delta}B=1^m^.834, , {Delta}V=2^m^.167, {Delta}R=2^m^.148, and {Delta}I=1^m^.912. The structure function showed that typical timescales for intraday variability were between approximately 2 and 7.5hr. The intraday variability amplitudes were from a few percent to approximately 30%. We found typical variation rates of approximately 0.05 mag/hr in both the rising and falling phases, with a minimal variability timescale of 130 minutes. A 10 day period short-term variability was observed simultaneously in the BVRI bands. The discrete correlation function suggests that there is significant correlated variability between the B- and I-band light curves. However, no significant time lags were detected. The spectral behaviors in the different variability episodes were studied, and our observations show bluer-when-brighter behavior on long, short, and intraday timescales for the blazar S5 0716+714. The variability and relevant spectral trends can be explained by the shock-in-jet scenario.
- ID:
- ivo://CDS.VizieR/J/AJ/155/31
- Title:
- 2005-2012 BVRI observations of blazar S5 0716+714
- Short Name:
- J/AJ/155/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to search for the evidence of quasi-periodic oscillation (QPO) in blazars, multicolor optical observations of the BL Lacertae object S5 0716+714 were performed from 2005 to 2012. For I band observations on 2010 March 19 with low variability amplitude and low flux level, the same QPO~50 minutes at the 99% significance level is confirmed by the ZDCF method, Lomb-Scargle method, REDFIT, and fitting sinusoidal curves. The observed QPO is likely to be explained by accretion disk variability. If the observed QPO indicates an innermost stable orbital period from the accretion disk, the QPO~50 minutes corresponds to a black hole mass of 5.03x10^6^ M_{sun}_ for a non-rotating Schwarzschild black hole and 3.2x10^7^ M_{sun}_ for a maximally rotating Kerr black hole.
- ID:
- ivo://CDS.VizieR/J/AJ/138/845
- Title:
- BVRI observations of 235 bright quasars
- Short Name:
- J/AJ/138/845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric observations of 235 extragalactic objects that are potential targets for the Space Interferometry Mission (SIM) are presented. Mean B, V, R, I magnitudes at the 5% level are obtained at 1-4 epochs between 2005 and 2007 using the 1m telescopes at Cerro Tololo Inter-American Observatory and the Naval Observatory Flagstaff Station. Of the 134 sources that have V magnitudes in the Veron & Veron-Cetty catalog (Cat. VII/248), a difference of over 1.0mag is found for the observed-catalog magnitudes for about 36% of the common sources, and 10 sources show over 3mag difference. Our first set of observations presented here form the basis of a long-term photometric variability study of the selected reference frame sources to assist in mission target selection and to support QSO multicolor photometric variability studies in general.
- ID:
- ivo://CDS.VizieR/J/ApJS/142/71
- Title:
- BVRI observations of LMC Cepheids
- Short Name:
- J/ApJS/142/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A homogeneous set of ground-based BVRI observations of ~600 Cepheids is presented to check the Cepheid period-luminosity (PL) zero point for the Large Magellanic Cloud (LMC). The sample of Cepheids is completely self-contained and has been reduced consistently to eliminate photometric differences caused by combining multiple sources of photometry. The Cepheid distances to nearby galaxies obtained by the Hubble Space Telescope (HST) Key Project on the Extragalactic Distance Scale were computed assuming a "standard" PL relation based on a compilation of photoelectric observations of 34 Cepheids and a standard distance modulus to the LMC of 18.50. The final Key Project results substituted a statistically stronger PL relation obtained by the OGLE collaboration. In this paper we compare our data with the OGLE PL relation; the subsample of LMC Cepheids with similar periods to those discovered in the nearby galaxies is fainter at the relevant periods by 0.04+/-0.02mag than the OGLE sample. Substituting in turn this PL relation for that of the OGLE collaboration would raise the Hubble constant by 2%+/-1%, a correction which is not significant. The multicolor data set will also be useful in considering the effects of reddening and chemical composition and deriving an improved Cepheid period-luminosity relation for the LMC.
- ID:
- ivo://CDS.VizieR/J/A+A/556/A60
- Title:
- BVRI observations of the FUor star V582 Aur
- Short Name:
- J/A+A/556/A60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from optical photometric and spectroscopic observations of the eruptive pre-main sequence star V582 Aur. Variability of the star was reported a few years ago when it was suspected as a possible FU Orionis object. Due to the small number of currently known FUors, a new object of this type is ideal target for follow-up photometric and spectroscopic observations. We carried out BVRI CCD photometric observations in the field of V582 Aur from 2009 August to 2013 April. We acquired high-, medium-, and low-resolution spectroscopy of V582 Aur during this period. To study the pre-outburst variability of the target and construct its historical light curve, we searched for archival observations in photographic plate collections. The pre-outburst photographic observations of V582 Aur show low-amplitude light variations typical of T Tauri stars. Archival photographic observations indicate that the increase in brightness began in late 1984 or early 1985 and the star reached the maximum level of brightness at 1986 January. Our BVRI photometric observations show large amplitude variations ({Delta}V~2.8mag.) during the 3.5 year period of observations. Most of the time, however, the star remains in a state close to the maximum brightness. The deepest drop in brightness was observed in the spring of 2012, when the brightness of the star fell to a level close to the pre-outburst. The multicolor photometric data show a color reversal during the minimum in brightness, which is typical of UX Ori variables.
- ID:
- ivo://CDS.VizieR/J/AJ/142/99
- Title:
- BVRI observations of TZ Boo
- Short Name:
- J/AJ/142/99
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New CCD photometric BVRI observations of the puzzling W UMa type binary star, TZ Bootis, are presented from our observations in 2010. By using the updated version of the Wilson-Devinney code, the first modern photometric solution is deduced from new photometric observations and published spectroscopic data.
- ID:
- ivo://CDS.VizieR/J/other/Ap/48.304
- Title:
- BVRI of comparison stars in AGN fields
- Short Name:
- J/other/Ap/48.30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are presented from CCD BVRI-observations of 145 comparison stars in the neighborhoods of 14 Seyfert galaxies, 3 quasars, and 5 BL Lac objects with right ascensions of 12 to 24 hours. The magnitudes of the observed stars ranged from V=11 to V=17. The typical photometric error for stars brighter V=14 is 0.01m. The B, V, Rc, and Ic magnitudes of most of these stars were not known previously. 14'x14' finding charts are provided. These results can be used for differential photometry of the nuclei of active galaxies in the B, V, Rc, and Ic bands.
- ID:
- ivo://CDS.VizieR/J/ApJ/832/125
- Title:
- BVRI photometric obs. of the PNe NGC 6337 & Sp 1
- Short Name:
- J/ApJ/832/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A current issue in the study of planetary nebulae with close binary central stars (CSs) is the extent to which the binaries affect the shaping of the nebulae. Recent studies have begun to show a high coincidence rate between nebulae with large-scale axial or point symmetries and close binary stars. In addition, combined binary-star and spatiokinematic modeling of the nebulae have demonstrated that all of the systems studied to date appear to have their central binary axis aligned with the primary axis of the nebula. Here we add two more systems to the list, the CSs and nebulae of NGC 6337 and Sp 1. We show both systems to be low inclination, with their binary axis nearly aligned with our line of sight. Their inclinations match published values for the inclinations of their surrounding nebulae. Including these two systems with the existing sample statistically demonstrates a direct link between the central binary and the nebular morphology. In addition to the systems' inclinations we give ranges for other orbital parameters from binary modeling, including updated orbital periods for the binary CSs of NGC 6337 and Sp 1.
- ID:
- ivo://CDS.VizieR/J/AJ/130/234
- Title:
- BVRI photometry and radial velocities of AV Del
- Short Name:
- J/AJ/130/234
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic and BVRI photometric observations of the double-lined eclipsing binary AV Del (period=3.85days) conducted over six observing seasons.
- ID:
- ivo://CDS.VizieR/J/A+AS/126/73
- Title:
- BVRI photometry in dark globules
- Short Name:
- J/A+AS/126/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using a CCD detector, BVRI photometry has been carried out in the vicinity of nine Lynds dark nebulae. In conjunction with spectroscopic data which could be obtained at a later stage, the data listed herein could be used for possible distance determinations of the nine nebulae.
- ID:
- ivo://CDS.VizieR/J/AJ/122/1125
- Title:
- BVRI photometry in 3 high-z clusters
- Short Name:
- J/AJ/122/1125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New photometric and spectroscopic observations of galaxies in the directions of three distant clusters are presented as part of our ongoing high-redshift cluster survey. The clusters are Cl 1324+3011 at z=0.76, Cl 1604+4304 at z=0.90, and Cl 1604+4321 at z=0.92. We have spectroscopically confirmed cluster membership for 2040 galaxies in each system and have also obtained spectra for over 280 field galaxies spanning the range 0<z<2.5.
- ID:
- ivo://CDS.VizieR/J/A+A/419/167
- Title:
- BVRI photometry in metal-poor binaries
- Short Name:
- J/A+A/419/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explored the regions within a radius of 25 arcsec around 473 nearby, low-metallicity G- to M-type stars using (VR)I optical filters and small-aperture telescopes. About 10% of the sample was searched up to angular separations of 90 arcsec. We applied photometric and astrometric techniques to detect true physical companions to the targets. The great majority of the sample stars was drawn from the Carney-Latham surveys; their metallicities range from roughly solar to [Fe/H]=-3.5dex. Our I-band photometric survey detected objects that are between 0 and 5mag fainter (completeness) than the target stars; the maximum dynamical range of our exploration is 9mag.
- ID:
- ivo://CDS.VizieR/J/AJ/145/165
- Title:
- BVRI photometry in NGC 6496
- Short Name:
- J/AJ/145/165
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-quality BVRI photometric data in the field of globular cluster NGC6496 obtained with the SOAR Telescope Adaptive Module (SAM). Our observations were collected as part of the ongoing SAM commissioning. The distance modulus and cluster color excess as found from the red clump are (m-M)_V_=15.71+/-0.02mag and E(V-I)=0.28+/-0.02mag. An age of 10.5+/-0.5Gyr is determined from the difference in magnitude between the red clump and the subgiant branch. These parameters are in excellent agreement with the values derived from isochrone fitting. From the color-magnitude diagram we find a metallicity of [Fe/H]=-0.65dex and hence support a disk classification for NGC 6496. The complete BVRI data set for NGC6469 is made available in the electronic edition of the Journal.
- ID:
- ivo://CDS.VizieR/J/PASP/117/1325
- Title:
- BVRI photometry in NGC4147
- Short Name:
- J/PASP/117/1325
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New BVRI broadband photometry and astrometry are presented for the globular cluster NGC 4147, based upon measurements derived from 524 ground-based CCD images mostly either donated by colleagues or retrieved from public archives. We have also reanalyzed five exposures of the cluster obtained with WFPC2 on the Hubble Space Telescope in the F439W and F555W (B and V) filters.
- ID:
- ivo://CDS.VizieR/J/PASP/117/37
- Title:
- BVRI photometry in NGC 2419, Pal 4, and Pal 14
- Short Name:
- J/PASP/117/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results from work done to extend the Johnson-Cousins BVRI photometric standard sequence to faint levels of V~21mag in compact fields is presented. Such calibration and extension of sequences is necessary to fill a calibration gap if reliable photometry from modest aperture telescopes in space (e.g., the Hubble Space Telescope) or terrestrial telescopes with apertures exceeding 4m is to be done. Sequences like the ones presented here, which cover a large range in brightness as well as color, will allow photometric calibration to be done efficiently and will also make such work less prone to systematic sources of error. Photometry of stars in approximately 10'x10' fields around three globular clusters (NGC 2419, Pal 4, and Pal 14) are presented from data acquired over several photometric nights. In each field, several stars are measured in B, V, R, and I passbands, with standard errors in the mean less than 0.015mag from random errors, to levels fainter than V=21mag.
- ID:
- ivo://CDS.VizieR/J/AJ/122/38
- Title:
- BVRI photometry of Abell 2443
- Short Name:
- J/AJ/122/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present broadband photometry and provide a quantitative analysis of the structure of galaxies in the inner region of the Abell Cluster 2443 (z~0.1). The galaxy parameters have been derived by fitting a two-component model (Sersic r^1/n^ bulge and exponential disk) to a magnitude-limited sample. Using a new method of analysis that takes into account the effects of seeing on the structural parameters and considers ellipticity as an active parameter, we avoid systematic errors arising from assumptions of circular symmetry. Of the sample galaxies, 76% were classified with these models, while the rest were morphologically peculiar. For the spiral galaxies, the relation between n and B/D is consistent with the trend observed in nearby field galaxy samples. The Sersic index n (which can be considered as a concentration index) of the elliptical galaxies is correlated with the local surface density of the cluster. Monte Carlo simulations were used to check the reliability of the method and determine the magnitude selection criteria. Observations were obtained on 1998 August 19 at the 2.5 m Nordic Optical Telescope (NOT) at the Observatorio del Roque de los Muchachos on La Palma. The prime-focus CCD camera was used with pixel scale of 0.11"/pix, and the seeing ranged from FWHM 0.88" to 1".
- ID:
- ivo://CDS.VizieR/J/A+AS/128/315
- Title:
- BVRI photometry of blazars
- Short Name:
- J/A+AS/128/315
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of both BVRI CCD photometric monitoring and fast photometry for 8 blazars and variable quasars are presented. There is intraday variability for 6 blazars and very short timescales (minutes to two hours) variability for 5 objects. Implications for relativistic beaming are briefly discussed.
- ID:
- ivo://CDS.VizieR/J/A+AS/136/455
- Title:
- BVRI photometry of 3 BL Lac objects
- Short Name:
- J/A+AS/136/455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of optical photometric (BVRI) monitoring of three BL Lac objects over a time interval of about four years are presented. The sources are three classical radio-selected BL Lac objects, BL Lac, OJ 287 and PKS 0735+178. During our observation OJ 287 was in the stage of a large periodic outburst which consisted of at least two peaks. Almost all the observations obtained over consecutive nights detected intranight variations. In 1995 and 1996 BL Lac kept in faint states, with fewer and smaller rapid flares and fluctuations. On the contrary, in late 1997 BL Lac was at the stage of a large outburst, accompanied with much more large amplitude rapid flares and fluctuations. PKS 0735+178 was almost at its faint end from 1994 to early 1998. Over this time interval, the intraday variations and microvariations in PKS 0735+178 were rare and the amplitude was very small, except a rapid darkening of ~0.4mag on 24 January 1995. Previous work by Webb et al. (1988AJ.....95..374W), Wagner et al. (1996AJ....111.2187W) and Pian et al. (1997ApJ...486..784P) also showed the same behaviour of variability as BL Lac and PKS 0735+178 in BL Lac, S5 0716+714, PKS 2155-304, respectively. We propose that the motion of orientation of the relativistic jet in a BL Lac object be responsible for these variability behaviours.
- ID:
- ivo://CDS.VizieR/J/A+AS/132/83
- Title:
- BVRI photometry of 7 BL Lac objects
- Short Name:
- J/A+AS/132/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Seven BL Lac objects have been photometrically observed in an effort to study the difference of optical intraday variability between the radio-selected BL Lac objects (RBLs) and X-ray-selected BL Lac objects (XBLs). The objects we observed are selected arbitrarily. They are four RBLs, PKS 0735+178, PKS 0754+101, OJ 287 and BL Lac, and three XBLs, H 0323+022, H 0548-322 and H 2154-304. During the observation all of them exhibited microvariation, and H 0323+022 and H 0548-322 sometimes showed brightness oscillation. PKS 0735+178 and BL Lac were in their faint states and not very active. It seems that RBLs do not show microvariability more frequently than XBLs.
- ID:
- ivo://CDS.VizieR/J/AJ/134/778
- Title:
- BVRI photometry of candidate subdwarfs
- Short Name:
- J/AJ/134/778
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical (BVRI) photometric measurements of a sample of 564 candidate cool subdwarfs in the nearby halo are presented. The stars generally span the color range 0.4<(B-V)<1.8; hence, the sample is composed of early F- through early M-type stars on the subdwarf sequence. The sample is selected from the revised NLTT catalog of Gould and Salim and Salim and Gould via a reduced proper motion diagram. The photometry is precise and accurate; in particular, for stars with 9<V<13.5 the photometry is accurate to 0.013, 0.015, 0.012, and 0.013mag in V, B-V, V-R, and V-I, respectively. For stars with 13.5<V<16 the photometry is accurate to 0.022, 0.018, 0.013, and 0.018mag in the same bands.
- ID:
- ivo://CDS.VizieR/J/A+AS/144/481
- Title:
- BVRI photometry of five X-ray selected BL Lacs
- Short Name:
- J/A+AS/144/481
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical data obtained with the 1.05 m telescope of the Torino Astronomical Observatory for five X-ray selected BL Lacertae objects. The data are in the Johnson's B, V, and Cousins' R bands. As the observing periods include the pointings of the Satellite per Astronomia X ``Beppo'' (BeppoSAX), our optical information will be comparable with the X-ray observations for a better understanding of the properties of these objects. The present data also provide optical information on sources that have been rarely observed in the optical band. Variability on short time scales (a few days) was found only for 1ES 1959+650.
- ID:
- ivo://CDS.VizieR/J/A+AS/142/425
- Title:
- BVRI photometry of 6 galaxies
- Short Name:
- J/A+AS/142/425
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of the brightest stars in six nearby spiral and irregular galaxies with corrected radial velocities from 340 to 460km/s. Three of them are resolved into stars for the first time. Based on luminosity of the brightest blue stars we estimate the following distances to the galaxies: 5.0Mpc for NGC 784, 9.2Mpc for NGC 2683, 8.9Mpc for NGC 2903, 4.1Mpc for NGC 5204, 6.8Mpc for NGC 5474, and 8.7Mpc for NGC 5585.
- ID:
- ivo://CDS.VizieR/J/A+A/574/A33
- Title:
- BVRI photometry of high-mass X-ray binaries
- Short Name:
- J/A+A/574/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric observations of the field around the optical counterparts of high-mass X-ray binaries. Our aim is to study the long-term photometric variability in correlation with their X-ray activity and derive a set of secondary standard stars that can be used for time series analysis. We find that the donors in Be/X-ray binaries exhibit larger amplitude changes in the magnitudes and colours than those hosting a supergiant companion. The amplitude of variability increases with wavelength in Be/X-ray binaries and remains fairly constant in supergiant systems. When time scales of years are considered, a good correlation between the X-ray and optical variability is observed. The X-rays cease when optical brightness decreases. These results reflect the fact that the circumstellar disk in Be/X-ray binaries is the main source of both optical and X-ray variability. We also derive the colour excess, E(B-V), selecting data at times when the contribution of the circumstellar disk was supposed to be at minimum, and we revisit the distance estimates.
- ID:
- ivo://CDS.VizieR/J/A+A/333/952
- Title:
- BVRI photometry of HR 1105
- Short Name:
- J/A+A/333/952
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRI photometry of the extrinsic S star HR 1105 shows a stable periodic light variability with a period of 24.76 days superimposed upon long term changes presumably related to the orbital period. The variations are in phase for all four magnitudes with the amplitude of this variability being about the same for B and V, but smaller for R and even smaller for I. As the primary is a M3 III star, these brightness changes are mostly likely due to the pulsation of the primary star.
- ID:
- ivo://CDS.VizieR/J/AJ/134/2286
- Title:
- BVRI photometry of isolated spirals
- Short Name:
- J/AJ/134/2286
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A release of multicolor broadband (BVRI) photometry for a subsample of 44 isolated spirals drawn from the Catalogue of Isolated Galaxies is presented. Total magnitudes and colors at various circular apertures, as well as some global structural/morphological parameters, are estimated. Morphology is reevaluated through optical and sharp-filtered R-band images, (B-I) color index maps, and archived near-IR JHK images from the Two Micron All Sky Survey. The CAS structural parameters (concentration, asymmetry, and clumpiness) were calculated from the images in each of the bands.
- ID:
- ivo://CDS.VizieR/J/A+A/380/347
- Title:
- BVRI photometry of 27 Kuiper Belt Objects
- Short Name:
- J/A+A/380/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present visible (BVRI) photometric measurements of 27 Trans-Neptunian objects, obtained with the FORS2 instrument on the ESO/8m Very Large Telescope (Unit 2) from runs during September and November 2000. The objects display a broad and continuous range of colors from neutral-bluish to very red. Most of the objects also have a linear reflectivity spectrum over the VRI range. There is no evidence of a bimodal color distribution as has been previously reported by other groups. Several objects (1994 TB, 1995 SM_55_, 1998 UR_43_, 1999CF_119_ and 2000 OK_67_) show evidence of changing color, and should be investigated further. The object 1995 SM_55_ deserves a more complete study since its neutral-blue colors suggest it could be a good candidate for hosting cometary activity.
- ID:
- ivo://CDS.VizieR/J/MNRAS/386/1380
- Title:
- BVRI photometry of LMC star clusters
- Short Name:
- J/MNRAS/386/1380
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a CCD photometric and mass function study of nine young Large Magellanic Cloud star clusters, namely NGC 1767, 1994, 2002, 2003, 2006, SL 538, NGC 2011, 2098 and 2136. BVRI data, reaching down to V~21mag, were collected from the 3.5-m NTT/EFOSC2 in subarcsec seeing conditions. For NGC 1767, 1994, 2002, 2003, 2011 and 2136, broad-band photometric CCD data are presented for the first time.
- ID:
- ivo://CDS.VizieR/J/AJ/154/81
- Title:
- BVRI photometry of luminous stars in M31 and M33
- Short Name:
- J/AJ/154/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first four years of BVRI photometry from an on-going survey to annually monitor the photometric behavior of evolved luminous stars in M31 and M33. Photometry was measured for 199 stars at multiple epochs, including 9 classic Luminous Blue Variables (LBVs), 22 LBV candidates, 10 post-RGB A/F type hypergiants, and 18 B[e] supergiants. At all epochs, the brightness is measured in the V-band and at least one other band to a precision of 0.04-0.10 mag down to a limiting magnitude of 19.0-19.5. Thirty three stars in our survey exhibit significant variability, including at least two classic LBVs caught in S Doradus-type outbursts. A hyperlinked version of the photometry catalog is at http://go.uis.edu/m31m33photcat
- ID:
- ivo://CDS.VizieR/J/A+AS/142/347
- Title:
- BVRI photometry of NGC 6789
- Short Name:
- J/A+AS/142/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the results of a detailed B, V, R, I, and H{alpha} study of the isolated nearby blue compact dwarf (BCD) galaxy NGC 6789. The observed galaxy has not yet been resolved into stars up to now. On CCD frames obtained with 6m BTA telescope and 2.5m Nordic telescope the galaxy is well resolved. Its colour-magnitude diagram confirms the two component (core-halo) galaxy morphology, which consists of two stellar populations distinct in structure and colour: an inner high surface-brightness young population within 150pc from the center of the galaxy, and a relatively low surface-brightness intermediate-age population extending out to at least 600pc. The distance to the galaxy, estimated from the tip of the red giant branch (TRGB) is 2.1Mpc which places NGC 6789 close to the Local Group. From the mean colour of the RGB, the mean metal abundance of the halo population is estimated as [Fe/H]=~-1dex.
- ID:
- ivo://CDS.VizieR/J/A+A/345/521
- Title:
- BVRI photometry of NGC 2264
- Short Name:
- J/A+A/345/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The pre-main-sequence (PMS) population in the mass range between =~0.2 and =~3M_{sun}_ in southern part of the star-forming region NGC 2264 has been studied, determining both the Initial Mass Function in the region as well as the star-formation rates for different mass ranges. The sample is a composite one, derived through the union of samples obtained through different techniques and each suffering from different biases: previously known PMS stars in the region from the literature, photometrically-selected T Tauri candidates (from our own photometric data, discussed in detail in the present paper) and X-ray selected PMS candidates (discussed in detail in a companion paper) have been joined to form a sample which we show to be statistically complete (i.e. free from the biases which affect each of the parent samples) down to =~0.6M_{sun}_ (while being incomplete at lower masses). Individual masses and ages have been derived by placing the individual stars on evolutionary tracks, allowing us to derive both the IMF and the star formation rate. The Initial Mass Function thus derived for NGC 2264 shows evidence for a bimodal distribution of masses, with a break in the IMF at around 1M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/other/NewA/27.25
- Title:
- BVRI photometry of Nova KT Eri 2009
- Short Name:
- J/other/NewA/27.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained extensive new BVRcIc photometry of Nova KT Eri 2009 over a 539-day interval during the post-outburst quiescence, from 30 September 2011 to 22 March 2013 (days +684 to +1223 past maximum). The median magnitudes we measured are B=15.24, V=15.00, Rc=14.75 and Ic=14.49. A marked variability is present (total amplitude of {Delta}V=1.6mag). Accounting for a generally overlooked correction to blue photographic magnitudes calibrated against modern B-band data, we found that mean brightness and amplitude of variability of KT Eri in quiescence are the same before and after the 2009 nova outburst. The distance to KT Eri derived from standard relations involving the absolute magnitude at maximum vs rate of decline (MMRD), is ~6.5kpc. At such a distance, to fit the BVRcIc + JHK flux distribution of KT Eri in quiescence requires an 8200K blackbody with a radius of 3.5R_{sun}_, which is vastly larger than the radius of typical accretion disks of CVs and classical old novae (0.1R_{sun}_). The distance to KT Eri could therefore be much shorter than expected from MMRD relation. We also observed a new eclipse-like minimum to occur right on time following the 752 day period suspected to modulate the quiescence of KT Eri before the outburst. The nature of this period remains unclear. The faintness of KT Eri at infrared wavelengths (K=14.1) precludes it from being the orbital period of the accreting WD, because in such a case the Roche lobe filling companion would be a cool giant shining at K~9mag.
- ID:
- ivo://CDS.VizieR/J/other/PZ/30.4
- Title:
- BVRI photometry of nova V445 Pup
- Short Name:
- J/other/PZ/30.4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- V445 Pup was a peculiar nova having no hydrogen spectral lines in the outburst. The spectrum contained strong emission lines of carbon, oxygen, calcium, sodium and iron. We have performed digital processing of photographic images of the V445 Pup progenitor using astronomical plate archives. The brightness of the progenitor in the B band was 14.3mag. It was found to be a periodic variable star, its most probable period being 0d.650654+/-0.000011d. The light curve shape suggests that the progenitor was a common-envelope binary having a spot on the surface and variable surface brightness. The spectral energy distribution of the progenitor between 0.44 and 2.2um was similar to that of an A0V type star.
- ID:
- ivo://CDS.VizieR/J/A+AS/129/569
- Title:
- BVRI photometry of OJ 287
- Short Name:
- J/A+AS/129/569
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of BVRI CCD photometric monitoring and fast photometry in the I band for the blazar OJ 287 in 1994-1995 are presented. The predicted outburst of the blazar had been observed, the maximum appeared in 1994 November, after that, the luminosity decreased by 1.6mag for about three months and dropped to near the level in 1994 April. Rapid variations with timescales of minutes, hours and one day were observed in our observations, with small amplitude. The amplitude of the most rapid variations (minutes) is in the range of 0.043-0.12mag . The results of the statistical analysis of the fast photometry data are as follows. In five nights out of six rapid variability appeared in the sampling interval, which ranged from 3.4 minutes to 6.5 minutes, with a rms amplitude of flux variations of 1.70%-2.3%. The rapid variability can be explained by the model of shocks within turbulent jet or of vortices and magnetic flux tubes on accretion disk.
- ID:
- ivo://CDS.VizieR/J/AN/326/3
- Title:
- BVRI photometry of 4 open clusters
- Short Name:
- J/AN/326/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD photometry of the galactic open clusters NGC 2627, NGC 5617, Pismis 7, and Ruprecht 75 is presented. For the first cluster, BV data are given, for the others the data are BV(RI)_c. The star coordinates are relative to the corresponding cluster center. The observations were carried out from the Complejo Astronomico El Leoncito (Argentina), and from Las Campanas (Chile). Each cluster was observed on two different nights; when possible, measurements for a given star were averaged. NGC 2627 observations were carried out from CASLEO on the nights of 7-8 January 1997 and 23-24 April 2001, in the BV filters. NGC 5617 data in the BVRI filters were obtained at Las Campanas on the nights 10-11 and 11-12 April 1996, and at CASLEO on the 1-2 April 2001 night. Pismis 7 was observed from Campanas on the 13-14 and 15-16 April 1996 nights (BVRI). Ruprecht 75 data in the BVRI filters were obtained at Las Campanas on the 12-13 April 1996 night, and at CASLEO on the 20-21 April 2001 night.
- ID:
- ivo://CDS.VizieR/J/A+A/423/935
- Title:
- BVRI photometry of OQ 530
- Short Name:
- J/A+A/423/935
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results of VLBI and optical observations are presented for the BL Lac object OQ 530 (B1418+546), whose long-term optical variability is characterised by a decreasing mean luminosity trend. EVN images at 1.6GHz and 5GHz of OQ 530 show a very bright core with a much weaker jet extending to about 35-40mas. The radio flux density from the core in June 2001 was much higher than that measured in February 1999. A similar increase was also found from nearly simultaneous optical photometry, while the total flux density of the jet remained unchanged. The structure of the jet shows several knots which move outward with an apparent superluminal motion with a beta_app_>=3.5h^-1^. The region within about 3mas from the core contains a component not well resolved in our images and emerging from it in the jet direction. That component was also detected in images taken from 1990 to 1997 and it seems to be a rather stable structural feature. Using nearly simultaneous optical and radio data, we can describe the SED of the synchrotron peak with a simple formula, approximating a power law at low frequencies and a log-parabola at the high ones, whose maximum lies in the range 3.5-5x10^13^Hz, and the extrapolation in the X-ray range give a flux comparable to that observed with BeppoSAX.
- ID:
- ivo://CDS.VizieR/J/other/BAJ/24.62
- Title:
- BVRI Photometry of 14 PMS stars
- Short Name:
- J/other/BAJ/24.6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New photometric data from CCD multicolour BVRI observations of 14 pre-main sequence stars during the period from 2013 April to 2015 September are presented. The studied objects are located in the field of 'Gulf of Mexico' in the NGC 7000/IC 5070 star-forming complex. The stars from our study exhibit different types of photometric variability in all optical passbands. Using our long-term observations and data published by other authors, we tried to define the reasons for the observed brightness variations. On the basis of our new data previously unknown periodicity in the light curve of the star LkHa 189 (2.45-days) was registered.
- ID:
- ivo://CDS.VizieR/J/other/BAJ/22.3
- Title:
- BVRI photometry of 5 PMS stars
- Short Name:
- J/other/BAJ/22.3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new data from BVRI photometric observations of five PMS stars during the period from April 2013 to July 2014. The stars are located in the field of NGC 7000/IC 5070 ("Gulf of Mexico") - a region with active star formation. The presented paper is a continuation of our long-term photometric investigations of the young stellar objects in this region. The long-term multicolor photometric observations of PMS stars are very important for their exact classification. Our results show that the studied stars exhibit different types of photometric variability in all bands. We tried to classify them using our data from the long-term photometry and data published by other authors.
- ID:
- ivo://CDS.VizieR/J/AJ/161/292
- Title:
- BVRI photometry of pre-W UMA binary V642 Virginis
- Short Name:
- J/AJ/161/292
- Date:
- 16 Mar 2022 00:08:32
- Publisher:
- CDS
- Description:
- V642Vir is a polar spotted, well-detached, UV Leo-type, low-mass, pre-WUMa (T1~4250K, ~K6V) eclipsing binary. It was observed in 2020 April, May, and June at the Dark Sky Observatory in North Carolina, USA with the 0.81m reflector of Appalachian State University. A total of 88 timings were used in our 22-year period study which included 12 Transiting Exoplanet Survey Satellite (TESS) timings. The O-C plots show a low-amplitude oscillation of residuals that points to the existence of an orbiting third body, a dwarf of minimum mass, 0.15M{sun} in an eccentric orbit (e=0.41), with an orbital period of 20.07yr. The odd light curves of V642 Virginis indicate that it has polar spots similar to UV Leo and the recently published V1023Per. Its present large polar spot region indicates that it must have a strong magnetic field and that it is synchronously rotating. The BVR_c_I_c_ simultaneous Wilson-Devinney Program solution gives a detached binary (primary and secondary components are underfilling their respective Roche Lobes, with 76% and 78% fill outs respectively). The cool spot region models near the pole of the primary component (centered at 10{deg} colatitude) and is angled toward the secondary component. Its large radius (68{deg}) and T-fact (T_spot_/T_surface_=0.69) also attest to the conclusion of the strength of the magnetic field. The small {Delta}T in the components (~318K) and mass ratio near unity (0.9542{+/-}0.0005) show that the stars are similar in spectral type (secondary ~K9V). The inclination is high, ~86.87{+/-}0.04{deg}, yet there is no time of constant light due to the two stars essentially equal radii.
- ID:
- ivo://CDS.VizieR/J/AZh/79/589
- Title:
- BVRI photometry of RC galaxies
- Short Name:
- J/AZh/79/589
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRI data are presented for the majority of steep-spectrum objects in the RATAN-600 7.6cm catalog (RC) catalog with m(R)<23.5mag. Previously developed programs are applied to these data to estimate the redshifts and age of the stellar population of the host galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/450/39
- Title:
- BVRI photometry of 8 red blazars
- Short Name:
- J/A+A/450/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 2482 BVRI photometric data on eight red blazars taken from 3 Observatories in the period 2003 September - 2004 February are presented. A table is given, containing the source name, the observation time, the source magnitude, the error on the source magnitude, the photometric band, and a label indicating the Observatory where the observation was done.
- ID:
- ivo://CDS.VizieR/J/ApJ/783/83
- Title:
- BVRI photometry of S5 0716+714
- Short Name:
- J/ApJ/783/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- S5 0716+714 is a typical BL Lacertae object. In this paper we present the analysis and results of long-term simultaneous observations in the radio, near-infrared, optical, X-ray, and {gamma}-ray bands, together with our own photometric observations for this source. The light curves show that the variability amplitudes in {gamma}-ray and optical bands are larger than those in the hard X-ray and radio bands and that the spectral energy distribution (SED) peaks move to shorter wavelengths when the source becomes brighter, which is similar to other blazars, i.e., more variable at wavelengths shorter than the SED peak frequencies. Analysis shows that the characteristic variability timescales in the 14.5GHz, the optical, the X-ray, and the {gamma}-ray bands are comparable to each other. The variations of the hard X-ray and 14.5GHz emissions are correlated with zero lag, and so are the V band and {gamma}-ray variations, which are consistent with the leptonic models. Coincidences of {gamma}-ray and optical flares with a dramatic change of the optical polarization are detected. Hadronic models do not have the same natural explanation for these observations as the leptonic models. A strong optical flare correlating a {gamma}-ray flare whose peak flux is lower than the average flux is detected. The leptonic model can explain this variability phenomenon through simultaneous SED modeling. Different leptonic models are distinguished by average SED modeling. The synchrotron plus synchrotron self-Compton (SSC) model is ruled out because of the extreme input parameters. Scattering of external seed photons, such as the hot-dust or broad-line region emission, and the SSC process are probably both needed to explain the {gamma}-ray emission of S5 0716+714.
- ID:
- ivo://CDS.VizieR/J/AJ/119/777
- Title:
- BVRI photometry of Sagittarius dwarf irregular galaxy
- Short Name:
- J/AJ/119/777
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep BVRI CCD photometry of the stars in the dwarf irregular galaxy SagDIG, obtained on the photometric night of 1994 October 8 (UT) using the University of Hawaii 2.2 m telescope at Mauna Kea.
- ID:
- ivo://CDS.VizieR/J/AJ/154/42
- Title:
- BVRI photometry of S5 0716+714 in 2012
- Short Name:
- J/AJ/154/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We monitored the BL Lacertae object S5 0716+714 in the optical bands during 2012 January and February with long time spans on intraday timescales (>5hr) and high time resolutions. During this monitoring period, the object shows violent flaring activity in both short and intraday timescales. The object has a high duty cycle. The light curves detected as intraday variability show variability of various shapes. The variability amplitude is from 12.81% to 33.22%, and the average value is 19.92%+/-5.87%. The overall magnitude variabilities are {Delta}B=1.24^m^, {Delta}V=1.42^m^, {Delta}R=1.3^m^, and {Delta}I=1.23^m^. During the observations, the average change rate is <CR>{=}0.035+/-0.009Mag/h during the ascent and <CR>{=}0.035+/-0.014Mag/h during the descent. However, different cases are found on certain nights. There are good interband correlations but no significant time lags for intraday and short timescales. The results of the autocorrelation function show that the variability timescales range from 0.054 to 0.134 day. Most nights show a bluer-when-brighter (BWB) chromatic trend, a weak redder-when-brighter (RWB) trend is found, and a few nights show no correlation between magnitude and color index. The BWB trend appears in short timescales. During the flare, the spectral index exhibits a clockwise loop for internights. A shock-in-jet model and the shock wave propagating along a helical path are likely to explain the variability and color index variability.
- ID:
- ivo://CDS.VizieR/J/other/Obs/116.382
- Title:
- BVRI Photometry of Spectroscopic Binaries
- Short Name:
- J/other/Obs/116.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRI photometry has been obtained for 82 of the spectroscopic binaries with orbits published in The Observatory by Griffin and his collaborators. The observations were obtained on nineteen nights during 1994-95. Given here are the star name, Griffin's paper number for the spectroscopic orbit, the abbreviated calendar date and heliocentric Julian Date (HJD) of the observation, the derived V, (B-V), (V-R)c, and (R-I)c values, and the phase in the spectroscopic orbit. The mean photometric values are listed in the final entry for each star. One night of poor quality, 950128, was given half weight in forming the means. The rms error of a single observation is about 0.025 mag. for all indices.
- ID:
- ivo://CDS.VizieR/J/other/IBVS/5526
- Title:
- BVRI photometry of stars in BZ UMa field
- Short Name:
- J/other/IBVS/552
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The AAVSO has received 4270 CCD measurements of BZ UMa over four nights during its March, 2004 outburst. Analysis of the measurements reveals rapid flickering and quasiperiodic behaviour but no coherent periodicity (beyond the orbital period) and the notable absence of superhumps
- ID:
- ivo://CDS.VizieR/J/ApJ/764/114
- Title:
- BVRI photometry of stars in Orion A
- Short Name:
- J/ApJ/764/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend our previous study of the stellar population of L1641, the lower-density star-forming region of the Orion A cloud south of the dense Orion Nebula Cluster (ONC), with the goal of testing whether there is a statistically significant deficiency of high-mass stars in low-density regions. Previously, we compared the observed ratio of low-mass stars to high-mass stars with theoretical models of the stellar initial mass function (IMF) to infer a deficiency of the highest-mass stars in L1641. We expand our population study to identify the intermediate-mass (late B to G) L1641 members in an attempt to make a more direct comparison with the mass function of the nearby ONC. The spectral-type distribution and the K-band luminosity function of L1641 are similar to those of the ONC, but problems of incompleteness and contamination prevent us from making a detailed test for differences. We limit our analysis to statistical tests of the ratio of high-mass to low-mass stars, which indicate a probability of only 3% that the ONC and the southern region of L1641 were drawn from the same population, supporting the hypothesis that the upper-mass end of the IMF is dependent on environmental density.
- ID:
- ivo://CDS.VizieR/J/PASP/114/1382
- Title:
- BVRI photometry of Stock 1 stars
- Short Name:
- J/PASP/114/1382
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- BVRI photometry and J2000.0 positions have been obtained for stars in the field of the open cluster Stock 1. The photometry has been combined with available spectral types and proper motions to investigate cluster membership. We conclude that Stock 1 is a young cluster with a reddening of E(B-V)=0.16+/-0.04, a distance modulus of V_0_-M_V_=7.5+/-0.1, and an age of 300+/-50Myr.
- ID:
- ivo://CDS.VizieR/J/AJ/144/37
- Title:
- BVRI photometry of the eclipsing binary BS Vul
- Short Name:
- J/AJ/144/37
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed study of the close eclipsing binary BS Vulpeculae. Although it is relatively bright (V: 10.9-11.6mag) and belongs to short-periodic variable stars (P=0.48days), it is rather neglected. To perform a thorough period analysis, we collected all available photometric observations that span the time interval of 1898-2010. Observations include archive photographic plate measurements and visually determined eclipse minima timings done in 1979-2003, which were later shown to be biased to accommodate the existing linear ephemeris. Applying our own direct period analysis we found a well-defined shortening of the orbital period of dP/dt=-6.70(17)x10^-11^=-2.11(6)ms/yr, which implies a continual mass flow from the primary to the secondary component. Using the 2003 version of the Wilson-Van Hamme code, our new complete BV(IR)_C_ light curves were analyzed and the physical parameters of the system were derived. We found that BS Vul is a near contact binary system with the primary component filling its critical Roche lobe. The luminosity enhancement on the left shoulder of the secondary minimum shown in the light curves can be explained as a result of a persistent hot spot on the secondary due to the mass transfer from the primary component to the secondary one and heating the facing hemisphere of the secondary component, which is consistent with our result of period analysis. With the period decrease, BS Vul will evolve toward the contact phase. It is another good observational example as predicted by the theory of thermal relaxation oscillations.