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- ID:
- ivo://CDS.VizieR/J/AJ/153/231
- Title:
- BVR photometry of EPIC 211957146
- Short Name:
- J/AJ/153/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the multi-band photometric and spectroscopic study of an over-contact binary system, EPIC211957146. The light curves exhibit a variable O' Connell effect, confirmed from our observational data and the Kepler K2 data. The best photometric solution incorporating a dark spot over the primary component unveils that the system has a low-mass ratio (q~0.17) and a high inclination (i~85{deg}). To confirm the solution and constrain the uncertainty, Monte-Carlo simulations are performed and the results are reported. Based on the O-C diagram analysis, we see that the variable shows a period increase at the rate of dP/dt~1.06x10^-6^days/yr, which is higher than the theoretically predicted value. Presence of a third body having a period of ~16.23years is evident from the O-C diagram. No filled-in effect is observed in the H{alpha} line, while the effect is vividly present in the Na line. From the Kepler K2 data, we found that the primary and secondary minima exhibit an anti-correlated O-C variation followed by an erratic behavior. This is possibly caused by the longitudinal motion of the spot, and hence, we set a lower limit of ~40days for the spot modulation. We also observe a possibly associated photometric difference in the primary depth by comparing our light curves with Kepler K2 normalized light curves. This system has a low-mass ratio and a high fill-out factor, and, theoretically, such a physical configuration would lead to a merger.
- ID:
- ivo://CDS.VizieR/J/A+AS/125/71
- Title:
- BVR photometry of 10 ESO/SERC fields
- Short Name:
- J/A+AS/125/71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For calibration of ESO/SERC survey plates, photometric CCD sequences have been obtained for 10 ESO/SERC fields in the area 10h00m<R.A.<15h30m and -34deg<Decl.<-18deg. In Tables 2 to 20, the catalogue of the CCD sequences is given. It contains B, V and R magnitudes for 117 galaxies and 162 stars with 12.7<V<21.0. Column 2 gives the object type, S for star, G for galaxy. The positions were measured from scans of Schmidt plates with one of the PDS machines at the Astronomisches Institut, Muenster, Germany. Their accuracy is between 0.5 and 1.0arcsec.
- ID:
- ivo://CDS.VizieR/J/AJ/151/124
- Title:
- BVR photometry of IZ Mon and AR Dra
- Short Name:
- J/AJ/151/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multi-color photometric observations for two neglected near-contact binaries, IZ Mon (P=0.77980^d^) and AR Dra (P=0.67584^d^). By the aid of the updated W-D analysis code, the photometric solutions were deduced from the multi-color light curves (LCs). IZ Mon is a semi-detached binary with a mass ratio of q=0.388(+/-0.002) , while AR Dra is a detached star with a mass ratio of q=0.652(+/-0.002). The asymmetric LCs of IZ Mon were modeled by a hot spot on the secondary's surface, which may be attributed to mass transfer from the primary. Based on all collected eclipse times for two systems, we constructed their timing residual curves. The orbital period for IZ Mon may be continuously decreasing at a rate of dP/dt=-2.06(+/-0.04)days/yr, which may result from mass and angular momentum loss from the central system. For AR Dra, there exists a cyclic variation with a period of P_3_=104.9(+/-2.9)yr due to light-time orbit effect via the presence of the third body, whose mass is more than 0.28(+/-0.02)M_{Sun}_. Finally, two near-contact binaries, IZ Mon and AR Dra, will evolve into contact binaries.
- ID:
- ivo://CDS.VizieR/J/A+A/422/407
- Title:
- BVR photometry of MS0302+17
- Short Name:
- J/A+A/422/407
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the supercluster MS0302+17 (ClG 0302+17, z~0.42) using weak lensing analysis and deep wide field BVR photometry with the CFH12K camera. Using (B-V) vs (V-R) evolution tracks we identify early-type members of the supercluster, and foreground ellipticals. We derive a R band catalogue of background galaxies for weak lensing analysis. We compute the correlation functions of light and mass and their cross-correlation and test if light traces mass on supercluster, cluster and galaxy scales. We show that the data are consistent with this assertion. The {zeta}-statistic applied in regions close to cluster centers and global correlation analyses over the whole field converge toward the simple relation M/L=300+/-30M_{sun}_/L_{sun}_ in the B band. This independently confirms the earlier results obtained by Kaiser (1998ApJ...498...26K). If we model dark matter halos around each early-type galaxy by a truncated isothermal sphere, we find that a linear relation M{prop.to}L still holds. In this case, the average halo truncation radius is s_*_<~200(h_70_)^-1^kpc close to clusters cores whereas it reaches a lower limit of ~300(h_70_)^-1^kpc at the periphery. This change of s_*_ as a function of radial distance may be interpreted as a result of tidal stripping of early type galaxies. Nevertheless the lack of information on the spatial distribution of late-type galaxies affects such conclusions concerning variations of s_*_. Though all the data at hand are clearly consistent with the assumption that mass is faithfully traced by light from early-type galaxies, we are not able to describe in detail the contribution of late type galaxies. We however found it to be small. Forthcoming wide surveys in UV, visible, and near infrared wavelengths will provide large enough samples to extend this analysis to late-type galaxies using photometric redshifts.
- ID:
- ivo://CDS.VizieR/J/PAZh/21/596
- Title:
- BVR photometry of NGC 6584
- Short Name:
- J/PAZh/21/596
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Automatic stellar photographic BVR photometry reaching 1mag below the horizontal branch of NGC 6584, located at V~16.5mag, has been performed for this poorly studied globular cluster. One of the photoelectric standard stars used in our reductions appears to be variable. We also determined accurate coordinates of 52 variable stars in the cluster and around it.
- ID:
- ivo://CDS.VizieR/J/AJ/109/173
- Title:
- BVR photometry of NGC 6822
- Short Name:
- J/AJ/109/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our proposed method to study the star-formation histories in nearby irregulars is here applied to NGC 6822. To this purpose we have obtained accurate CCD photometry of three regions in the galaxy, reaching V=23.5 with the required accuracy of {sigma}_BVR_<=0.1mag. Major information on the stellar populations, star-formation rates, and initial mass functions of these regions in the last 1Gyr are derived from the comparison of the observational color-magnitude diagrams and luminosity functions with the corresponding synthetic diagrams and luminosity functions generated by a numerical simulation code based on stellar evolutionary tracks. We find that in the last 1Gyr the star-formation activity has been rather continuous, possibly occurring in long episodes of moderate activity separated by short quiescent periods, and that the initial mass function exponent a is in the vicinity of Salpeter's value, i.e., slightly flatter than in the solar neighborhood. The studied regions of NGC 6822 appear to contain different stellar populations. The preferred star formation regime for region A is a continuous activity coupled with a moderately flat {alpha}. For region C, instead, our best models suggest a discontinuous star formation and a moderately steep {alpha}. NGC 6822 is the last object of our original sample of five nearby irregulars. We can then draw the scenario resulting from this sample: most of the observed fields appear to have experienced a gasping regime of star formation, with average exponent {alpha}=2.35 for the initial mass function. Despite their small sizes, the majority of the sample galaxies contain different stellar populations in different regions.
- ID:
- ivo://CDS.VizieR/J/AJ/132/1593
- Title:
- BVR photometry of NGC 4594 globular clusters
- Short Name:
- J/AJ/132/1593
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed imaging analysis of the globular cluster (GC) system of the Sombrero galaxy (NGC 4594) has been accomplished using a six-image mosaic from the Hubble Space Telescope Advanced Camera for Surveys. The quality of the data is such that contamination by foreground stars and background galaxies is negligible for all but the faintest 5% of the GC luminosity function. This enables the study of an effectively pure sample of 659 GCs until ~2mag fainter than the turnover magnitude, which occurs at M^TOM^_V_=-7.60+/-0.06 for an assumed m-M=29.77. Two GC metallicity subpopulations are easily distinguishable, with the metal-poor subpopulation exhibiting a smaller intrinsic dispersion in color compared to the metal-rich subpopulation.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1599
- Title:
- B'V'R' photometry of S5 0716+714
- Short Name:
- J/AJ/133/1599
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We first introduce a novel photometric system that consists of a Schmidt telescope, an objective prism, a CCD camera, and, in particular, a multipeak interference filter. The multipeak interference filter enables light in multiple passbands to pass through it simultaneously. The light in different passbands is differentially refracted by the objective prism and is focused on the CCD in separate regions, so we have multiple "images" for each object on the CCD frames. This system enables us to monitor blazars exactly simultaneously in multiple wave bands on a single telescope and to accurately trace the color change during the variation. We used this novel system to monitor the BL Lacertae object S5 0716+714 during 2006 January and February and achieved a very high temporal resolution. The object was very bright and very active during this period. Two strong flares were observed, with variation amplitudes of about 0.8 and 0.6mag in the V' band, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/110/212
- Title:
- BVR photometry of stars in NGC 2366
- Short Name:
- J/AJ/110/212
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar content of the Im galaxy NGC 2366 is discussed on the basis of CCD BVR photometry. The three brightest blue and red stars have been used to estimate its distance, obtaining a value of 2.9pc. The spatial distribution of the young stellar population is discussed in the light of the integrated color indices and the color-magnitude diagrams of different zones of the galaxy. A generalized star formation burst seems to have taken place about 50Myr ago. The youngest stars are preferentially formed in the South-West part of the bar, where the giant H II complex NGC 2363 is located, being younger and bluer. The bar seems to play a role favoring star formation in one of its extremes. Self-propagation however, does not seem to be triggering star formation at large scale. A small region, populated by very young stars has also been found at the East of the galaxy.
