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- ID:
- ivo://CDS.VizieR/J/A+AS/122/51
- Title:
- B to G stars calibration in Geneva photometry
- Short Name:
- J/A+AS/122/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used recent Kurucz models and many standard stars to revise previous calibrations of the Geneva photometric parameters in terms of Teff, logg, and [M/H]. In addition, new parameters pT and pG were defined, which are the Geneva equivalents of Stromgren's a and r parameters and allow to estimate Teff and logg for stars with intermediate temperature (spectral type A0-A3). A fortran code (calib.f) has been written, which applies our calibration to stars measured in the Geneva system. A conspicuous change in slope appears in the grid d vs B2-V1. It seems to be linked with the onset of convection in the superficial layers of the star's envelope.
- ID:
- ivo://CDS.VizieR/J/MNRAS/393/1531
- Title:
- BUDDA structural properties of galaxies
- Short Name:
- J/MNRAS/393/1531
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed 2D bulge/bar/disc decompositions using g, r and i-band images of a representative sample of nearly 1000 galaxies from the Sloan Digital Sky Survey. We show that the Petrosian concentration index is a better proxy for the bulge-to-total ratio than the global Sersic index. We show that pseudo-bulges can be distinguished from classical bulges as outliers in the Kormendy relation. We provide the structural parameters and distributions of stellar masses of ellipticals, classical bulges, pseudo-bulges, discs and bars, and find that 32% of the total stellar mass in massive galaxies in the local universe is contained in ellipticals, 36% in discs, 25% in classical bulges, 3% in pseudo-bulges and 4% in bars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/440/1690
- Title:
- Bulge and disc colours of ETG in Coma
- Short Name:
- J/MNRAS/440/1690
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We explore the internal structure of red-sequence galaxies in the Coma cluster across a wide range of luminosities (-17>M_g_>-22) and cluster-centric radii (0<r_cluster_<1.3r_200_). We present the 2D bulge-disc decomposition of galaxies in deep Canada-France-Hawaii Telescope u, g, i imaging using GALFIT. Rigorous filtering is applied to identify an analysis sample of 200 galaxies which are well described by an 'archetypal' S0 structure (central bulge + outer disc).
- ID:
- ivo://CDS.VizieR/J/ApJS/196/11
- Title:
- Bulge+disk decompositions of SDSS galaxies
- Short Name:
- J/ApJS/196/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform two-dimensional, point-spread-function-convolved, bulge+disk decompositions in the g and r bandpasses on a sample of 1123718 galaxies from the Legacy area of the Sloan Digital Sky Survey Data Release Seven. Four different decomposition procedures are investigated which make improvements to sky background determinations and object deblending over the standard SDSS procedures that lead to more robust structural parameters and integrated galaxy magnitudes and colors, especially in crowded environments. We use a set of science-based quality assurance metrics, namely, the disk luminosity-size relation, the galaxy color-magnitude diagram, and the galaxy central (fiber) colors to show the robustness of our structural parameters. The best procedure utilizes simultaneous, two-bandpass decompositions. Bulge and disk photometric errors remain below 0.1mag down to bulge and disk magnitudes of g~19 and r~18.5. We also use and compare three different galaxy fitting models: a pure Sersic model, an n_b_=4 bulge+disk model, and a Sersic (free n_b_) bulge+disk model. The most appropriate model for a given galaxy is determined by the F-test probability. All three catalogs of measured structural parameters, rest-frame magnitudes, and colors are publicly released here.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/L25
- Title:
- Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR)
- Short Name:
- J/ApJ/821/L25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 947 radial velocities of RR Lyrae variable stars in four fields located toward the Galactic bulge, observed within the data from the ongoing Bulge RR Lyrae Radial Velocity Assay (BRAVA-RR). We show that these RR Lyrae stars (RRLs) exhibit hot kinematics and null or negligible rotation and are therefore members of a separate population from the bar/pseudobulge that currently dominates the mass and luminosity of the inner Galaxy. Our RRLs predate these structures and have metallicities, kinematics, and spatial distribution that are consistent with a "classical" bulge, although we cannot yet completely rule out the possibility that they are the metal-poor tail of a more metal-rich ([Fe/H]~-1dex) halo-bulge population.
- ID:
- ivo://CDS.VizieR/J/AJ/142/2
- Title:
- Burrell-Optical-Kepler-Survey (BOKS). I.
- Short Name:
- J/AJ/142/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the initial results of a 40 night contiguous ground-based campaign of time series photometric observations of a 1.39deg^2^ field located within the NASA Kepler Mission field of view. The goal of this pre-launch survey was to search for transiting extrasolar planets and to provide independent variability information of stellar sources. We have gathered a data set containing light curves of 54,687 stars from which we have created a statistical sub-sample of 13,786 stars between 14<r<18.5 and have statistically examined each light curve to test for variability. We present a summary of our preliminary photometric findings including the overall level and content of stellar variability in this portion of the Kepler field and give some examples of unusual variable stars found within. We present a preliminary catalog of 2,457 candidate variable stars, of which 776 show signs of periodicity. We also present three potential exoplanet candidates, all of which should be observable by the Kepler mission.
- ID:
- ivo://CDS.VizieR/J/A+A/463/981
- Title:
- BV CCD photometry in Westerlund 2
- Short Name:
- J/A+A/463/981
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The properties of the early-type stars in the core of the Westerlund 2 cluster are examined in order to establish a link between the cluster and the very massive Wolf-Rayet binary WR20a as well as the H II complex RCW 49. Photometric monitoring as well as spectroscopic observations of Westerlund 2 are used to search for light variability and to establish the spectral types of the early-type stars in the cluster core. The first light curves of the eclipsing binary WR 20a in B and V filters are analysed and a distance of 8kpc is inferred. Three additional eclipsing binaries, which are probable late O or early B-type cluster members, are discovered, but none of the known early O-type stars in the cluster displays significant photometric variability above 1% at the 1-sigma level. The twelve brightest O-type stars are found to have spectral types between O3 and O6.5, significantly earlier than previously thought. The distance of the early-type stars in Westerlund 2 is established to be in excellent agreement with the distance of WR20a, indicating that WR20a actually belongs to the cluster. Our best estimate of the cluster distance thus amounts to 8.0+/-1.4kpc. Despite the earlier spectral types, the currently known population of early-type stars in Westerlund 2 does not provide enough ionizing photons to account for the radio emission of the RCW 49 complex. This suggests that there might still exist a number of embedded early O-stars in RCW49.
- ID:
- ivo://CDS.VizieR/J/MNRAS/381/602
- Title:
- BV differential light curves of EQ Tau
- Short Name:
- J/MNRAS/381/602
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two new sets of complete light curves of EQ Tauri (EQ Tau) observed in 2000 October and 2004 December. These were analysed, together with the light curves obtained by Yang & Liu (2002AJ....124.3358Y) in 2001 December, with the 2003 version of the Wilson-Devinney code. In the three observing seasons, the light curves show a noticeable variation in the time-scale of years. The more massive component of EQ Tau is a solar-type star (G2) with a very deep convective envelope, which rotates about 80 times as fast as the Sun. Therefore, the change can be explained by dark-spot activity on the common convective envelope. The assumed unperturbed part of the light curve and the radial velocities published by Rucinski et al. (2001AJ....122.1974R) were used to determine the basic parameters of the system, which were kept fixed for spot modelling in the three sets of light curves. The results reveal that the total spotted area on the more massive component covers 18, 3 and 20 per cent of the photospheric surface in the three observing seasons, respectively. Polar spots and high-latitude spots are found. The analysis of the orbital period has demonstrated that it undergoes cyclical oscillation, which is due to either a tertiary component or periodic magnetic activity in the more massive component.
- ID:
- ivo://CDS.VizieR/J/AJ/133/1421
- Title:
- BV differential photometry of 11 gamma Dor stars
- Short Name:
- J/AJ/133/1421
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used precise photometric and high-dispersion spectroscopic observations to study 11 gamma Doradus stars, 10 of them newly confirmed. Only five of these 11 gamma Doradus stars appear to be single; two are primaries of double-lined spectroscopic binaries, one is the secondary of a double-lined binary, two are primaries of visual binaries and, in the case of the double-lined binary (HD 86371), either or both components could be a pulsating gamma Doradus star. We have determined a preliminary orbital period of 5.32 days for the double-lined binary HD 41547. Several of the stars show spectroscopic line-profile and low-amplitude radial velocity variability indicative of pulsation. All 11 stars are photometrically variable with amplitudes between 4 and 94 mmag in Johnson B and periods between 0.38 and 1.86 days. The 11 stars have between two and five independent periods.
