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8011. VRIJHK photometry of SN 2002cv
ID:
ivo://CDS.VizieR/J/MNRAS/384/107
Title:
VRIJHK photometry of SN 2002cv
Short Name:
J/MNRAS/384/107
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present VRIJHK photometry, and optical and near-infrared spectroscopy, of the heavily extinguished Type Ia supernova (SN Ia) 2002cv, located in NGC 3190, which is also the parent galaxy of the SN Ia 2002bo. SN 2002cv, not visible in the blue, has a total visual extinction of 8.74+/-0.21mag. In spite of this, we were able to obtain the light curves between 10 and +207d from the maximum in the I band, and also to follow the spectral evolution, deriving its key parameters. We found the peak I-band brightness to be I_max_=16.57+/-0.10mag, the maximum absolute I magnitude to be M_max_I=18.79+/-0.20, and the parameter {delta}m15(B) specifying the width of the B-band light curve to be 1.46+/-0.17mag. The latter was derived using the relations between this parameter and {delta}m40(I) and the time-interval {delta}t_max_(I) between the two maxima in the I-band light curve. As has been found for previously observed, highly extinguished SNe Ia, a small value of 1.59+/-0.07 was obtained here for the ratio RV of the total-to-selective extinction ratio for SN 2002cv, which implies a small mean size for the grains along the line of sight towards us. Since it was found for SN 2002bo a canonical value of 3.1, here we present a clear evidence of different dust properties inside NGC 3190.
8012. VRIJHK photometry of the Serpens cloud core
ID:
ivo://CDS.VizieR/J/A+A/330/990
Title:
VRIJHK photometry of the Serpens cloud core
Short Name:
J/A+A/330/990
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a deep optical (VRI) and near infrared (JHK) survey of the central part of the Serpens molecular cloud. A total of 138 sources were detected in the 19 arcmin^2^ surveyed area down to a limiting magnitude of 16.3 in K. We find that the form of the observed K Luminosity Function (KLF) of stars belonging to the Serpens Molecular cloud is consistent with that predicted from a Miller & Scalo (1979ApJS...41..513M) Interstellar Mass Function (IMF). We have investigated the KLF evolution with the age of a cluster by modeling KLFs of hypothetical clusters. Our results suggest that two phases of star formation could have taken place in the Serpens core.
8013. VRIJHK photometry of the T Tauri binary KH 15D
ID:
ivo://CDS.VizieR/J/AJ/155/47
Title:
VRIJHK photometry of the T Tauri binary KH 15D
Short Name:
J/AJ/155/47
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present VRIJHK photometry of the KH 15D T Tauri binary system for the 2015/2016 and 2016/2017 observing seasons. For the first time in the modern (CCD) era, we are seeing Star B fully emerge from behind the trailing edge of the precessing circumbinary ring during each apastron passage. We are, therefore, able to measure its luminosity and color. Decades of photometry on the system now allow us to infer the effective temperature, radius, mass, and age of each binary component. We find our values to be in good agreement with previous studies, including archival photographic photometry from the era when both stars were fully visible, and they set the stage for a full model of the system that can be constructed once radial velocity measurements are available. We also present the first high-sensitivity radio observations of the system, taken with the Atacama Large Millimeter/submillimeter Array and the Submillimeter Array. The respective 2.0 and 0.88 mm observations provide an upper limit on the circumbinary (gas and dust) disk mass of 1.7 M_Jup_ and reveal an extended CO outflow, which overlaps with the position, systemic velocity, and orientation of the KH 15D system and is certainly associated with it. The low velocity, tight collimation, and extended nature of the emission suggest that the outflow is inclined nearly orthogonal to the line of sight, implying it is also orthogonal to the circumbinary ring. The position angle of the radio outflow also agrees precisely with the direction of polarization of the optical emission during the faint phase. A small offset between the optical image of the binary and the central line of the CO outflow remains a puzzle and possible clue to the jet launching mechanism.
8014. VRIJK photometry of GQ Lup
ID:
ivo://CDS.VizieR/J/A+A/468/1039
Title:
VRIJK photometry of GQ Lup
Short Name:
J/A+A/468/1039
Date:
21 Oct 2021
Publisher:
CDS
Description:
We wanted to determine the rotation parameters of GQ Lup A, thereby constraining the evolutionary history of the GQ Lup system. We have undertaken a photometric monitoring campaign on GQ Lup A consisting of two epochs spaced one year apart. We also searched the photometric archives to enlarge the data set.
8015. VRI LCs of BL Lac object Mrk 501 from 2010 to 2015
ID:
ivo://CDS.VizieR/J/ApJS/222/24
Title:
VRI LCs of BL Lac object Mrk 501 from 2010 to 2015
Short Name:
J/ApJS/222/24
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have monitored the BL Lac object Mrk 501 in the optical V, R, and I bands from 2010 to 2015. For Mrk 501, the presence of a strong host galaxy component can affect the results of photometry. After subtracting the host galaxy contributions, the source shows intraday and long-term variabilities for optical flux and color indices. The average variability amplitudes of the V, R, and I bands are 22.05%, 22.25%, and 23.82%, respectively, and the value of the duty cycle is 14.87%. A minimal variability timescale of 106 minutes is detected. No significant time lag between the V and I bands is found on one night. The bluer-when-brighter (BWB) trend is dominant for Mrk 501 on intermediate, short, and intraday timescales, which supports the shock-in-jet model. For the long timescale, Mrk 501, in different states, can have different BWB trends. The corresponding results for non-correcting host galaxy contributions are also presented. We have monitored the BL Lac object Mrk 501 in the optical V, R, and I bands from 2010 to 2015. For Mrk 501, the presence of a strong host galaxy component can affect the results of photometry. After subtracting the host galaxy contributions, the source shows intraday and long-term variabilities for optical flux and color indices. The average variability amplitudes of the V, R, and I bands are 22.05%, 22.25%, and 23.82%, respectively, and the value of the duty cycle is 14.87%. A minimal variability timescale of 106 minutes is detected. No significant time lag between the V and I bands is found on one night. The bluer-when-brighter (BWB) trend is dominant for Mrk 501 on intermediate, short, and intraday timescales, which supports the shock-in-jet model. For the long timescale, Mrk 501, in different states, can have different BWB trends. The corresponding results for non-correcting host galaxy contributions are also presented.
8016. VRI light curve of 5 eclipsing binaries
ID:
ivo://CDS.VizieR/J/MNRAS/442/2620
Title:
VRI light curve of 5 eclipsing binaries
Short Name:
J/MNRAS/442/2620
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report 15 new VRI light curves of five low-mass eclipsing binaries (NSVS 02502726, NSVS 07453183, NSVS 11868841, NSVS 06550671 and NSVS 10653195) that were observed between 2010 and 2012. We analysed our new data together with three published spectroscopic observations and seven published light curves using a modified version of the Wilson-Devinney program. Orbital solutions of the five low-mass eclipsing binaries were revised and new star-spot parameters were obtained. We found that spot locations on the five low-mass eclipsing binaries changed over several years. However, the star-spots for NSVS 07453183 and NSVS 06550671 were stable for several months. More interestingly, for NSVS 02502726, the spots within a star-spot longitude region of 180{deg}-360{deg} indicated a magnetic activity cycle of 5.9(+/-0.2)yr. Moreover, we detected the first flare-like event on NSVS 07453183 at phase 0.39. The observations of the chromospheric activity indicators (H{beta} and H{gamma} lines) revealed that NSVS 10653195 and NSVS 06550671 were active. For NSVS 02502726, we found a weak continuous secular decrease at a smaller rate of dp/dt=-2.1(0.8)x10^-7^d/yr than the previous result. For NSVS 07453183, the O-C times appeared to increase at cycle 6000, and this was followed by a decrease at cycle 6500.
8017. VRI light curves of four contact binaries
ID:
ivo://CDS.VizieR/J/AJ/152/57
Title:
VRI light curves of four contact binaries
Short Name:
J/AJ/152/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new, high-quality multicolor observations of four recently discovered contact binaries, 1SWASP J064501.21+342154.9, 1SWASP J155822.10-025604.8, 1SWASP J212808.86+151622.0, and UCAC4 436-062932, and analyze their light curves to determine orbital and physical parameters using the modeling program of G. Djurasevic. In the absence of spectroscopic observations, the effective temperatures of the brighter components are estimated from the color indices, and the mass ratios are determined with the q-search method. The analysis shows that all four systems are W UMa type binaries in shallow contact configurations, consisting of late-type main-sequence primaries and evolved secondaries with active surface regions (dark or bright spots) resulting from magnetic activity or ongoing transfer of thermal energy between the components. We compare the derived orbital and stellar parameters for these four variables with a large sample of previously analyzed W UMa stars and find that our results fit it well.
8018. VRI light curves of GSC 1537-1557
ID:
ivo://CDS.VizieR/J/AJ/150/9
Title:
VRI light curves of GSC 1537-1557
Short Name:
J/AJ/150/9
Date:
21 Oct 2021
Publisher:
CDS
Description:
By analyzing R_c_ and I_c_light curves of the short-period solar-type eclipsing binary GSC 1537-1557 we discovered that it is a shallow contact binary with a degree of contact factor of f=(8.1+/-1.79)%. Photometric solutions reveal that GSC 1537-1557 is a W-type system with a mass ratio of q=M_2_/M_1_=2.645 where the less massive component (the primary star) is about 110K hotter than the more massive one (the secondary star). The asymmetry and variation of the light curves were explained as the activity of spots on the solar-type component stars. By investigating all of the available times of light minima, we found that the observed-calculated (O-C) curve shows a cyclic variation with a small amplitude of 0.00335days and a period of 8.1years. The small-amplitude cyclic change in the O -C curve was analyzed for the light-travel time effect via the presence of an extremely cool stellar companion. The mass of the third body was determined to be M_3_sini'=(0.19+/-0.01)M_{sun}_ when M_1_+M_2_=1.31M_{sun}_ is adopted for GSC 1537-1557. The semimajor axis of the outer obit is a'sini'=(4.58+/-0.33)AU.
8019. VrI light curves of NGC6981 variables
ID:
ivo://CDS.VizieR/J/MNRAS/413/1275
Title:
VrI light curves of NGC6981 variables
Short Name:
J/MNRAS/413/1275
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results from 10 nights of observations of the globular cluster NGC 6981 (M72) in the V, R and I Johnson wavebands. We employed the technique of difference image analysis to perform precision differential photometry on the time-series images, which enabled us to carry out a census of the understudied variable star population of the cluster. We show that 20 suspected variables in the literature are actually non-variable, and we confirm the variable nature of another 29 variables while refining their ephemerides. We also detect 11 new RR Lyrae variables and three new SX Phe variables, bringing the total confirmed variable star count in NGC 6981 to 43. We performed Fourier decomposition of the light curves for a subset of RR Lyrae stars and used the Fourier parameters to estimate the fundamental physical parameters of the stars using relations available in the literature. Mean values of these physical parameters have allowed us to estimate the physical parameters of the parent cluster. We derive a metallicity of [Fe/H]_ZW_~-1.48+/-0.03 on the Zinn & West scale (or [Fe/H]_UVES_~-1.38+/-0.03 on the new Carretta et al. scale) for NGC 6981, and distances of ~16.73+/-0.36 and ~16.68+/-0.36kpc from analysis of the RR0 and RR1 stars separately. We also confirm the Oosterhoff type I classification for the cluster, and show that our colour-magnitude data are consistent with the age of ~12.75+/-0.75Gyr derived by Dotter et al.
8020. VrI light curves of NGC1904 variables
ID:
ivo://CDS.VizieR/J/A+A/548/A92
Title:
VrI light curves of NGC1904 variables
Short Name:
J/A+A/548/A92
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the analysis of 11 nights of V and I time-series observations of the globular cluster NGC 1904 (M 79). Using this we searched for variable stars in this cluster and attempted to refine the periods of known variables, making use of a time baseline spanning almost 8 years. We use our data to derive the metallicity and distance of NGC 1904. We used difference imaging to reduce our data to obtain high-precision light curves of variable stars. We then estimated the cluster parameters by performing a Fourier decomposition of the light curves of RR Lyrae stars for which a good period estimate was possible. We also derive an estimate for the age of the cluster by fitting theoretical isochrones to our colour-magnitude diagram (CMD). Out of 13 stars previously classified as variables, we confirm that 10 are bona fide variables. We cannot detect variability in one other within the precision of our data, while there are two which are saturated in our data frames, but we do not find sufficient evidence in the literature to confirm their variability. We also detect a new RR Lyrae variable, giving a total number of confirmed variable stars in NGC 1904 of 11. Using the Fourier parameters, we find a cluster metallicity [Fe/H]_ZW_=-1.63+/-0.14, or [Fe/H]_UVES_=-1.57+/-0.18, and a distance of 13.3+/-0.4kpc (using RR0 variables) or 12.9kpc (using the one RR1 variable in our sample for which Fourier decomposition was possible).