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- ID:
- ivo://CDS.VizieR/J/ApJ/855/43
- Title:
- Distant RR Lyrae stars discovered with HiTS
- Short Name:
- J/ApJ/855/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of distant RR Lyrae stars, including the most distant known in the Milky Way, using data taken in the g-band with the Dark Energy Camera as part of the High cadence Transient Survey (HiTS; 2014 campaign). We detect a total of 173 RR Lyrae stars over a ~120deg^2^ area, including both known RR Lyrae and new detections. The heliocentric distances dH of the full sample range from 9 to >200kpc, with 18 of them beyond 90kpc. We identify three sub-groups of RR Lyrae as members of known systems: the Sextans dwarf spheroidal galaxy, for which we report 46 new discoveries, and the ultra-faint dwarf galaxies Leo IV and Leo V. Following an MCMC methodology, we fit spherical and ellipsoidal profiles of the form {rho}(R)~Rn to the radial density distribution of RR Lyrae in the Galactic halo. The best fit corresponds to the spherical case, for which we obtain a simple power-law index of n=-4.17_-0.20_^+0.18^, consistent with recent studies made with samples covering shorter distances. The pulsational properties of the outermost RR Lyrae in the sample (dH>90kpc) differ from the ones in the halo population at closer distances. The distribution of the stars in a period-amplitude diagram suggest they belong to Oosterhoff-intermediate or Oosterhoff II groups, similar to what is found in the ultra-faint dwarf satellites around the Milky Way. The new distant stars discovered represent an important addition to the few existing tracers of the Milky Way potential in the outer halo.
543. DK Cygni light curve
- ID:
- ivo://CDS.VizieR/J/A+A/289/137
- Title:
- DK Cygni light curve
- Short Name:
- J/A+A/289/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/650/A157
- Title:
- Dolidze 25 Chandra/ACIS-I X-ray sources
- Short Name:
- J/A+A/650/A157
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The dispersal of protoplanetary disks sets the timescale available for planets to assemble, and thus it is one of the fundamental parameters in theories of planetary formation. Disk dispersal is determined by several properties of the central star, the disk itself, and the surrounding environment. In particular, the metallicity of disks may impact their evolution, even if to date controversial results exist: in low-metallicity clusters disks seem to rapidly disperse, while in the Magellanic Clouds some evidence supports the existence of accreting disks few tens of Myrs old. In this paper we study the dispersal timescale of disks in Dolidze 25, the young cluster in proximity of the Sun with lowest metallicity, with the aim of understanding whether disk evolution is impacted by the low-metallicity of the cluster. We have analyzed Chandra/ACIS-I observations of the cluster and combined the resulting source catalog with existing optical and infrared catalogs of the region. We selected the disk-bearing population in a 1 degree circular region centered on Dolidze~25 from criteria based on infrared colors, and the disk-less population within a smaller central region among the X-ray sources with OIR counterpart. In both cases, criteria are applied to discard contaminating sources in the foreground/background. We have derived stellar parameters from isochrones fitted to color-magnitude diagrams. We derived a disk fraction of about 34% and a median age of the cluster of 1.2Myrs. To minimize the impact of incompleteness and spatial inhomogeneity of the list of members, we restricted this calculation to stars in a magnitude range where our selection of cluster members is fairly complete and by adopting different cuts in stellar masses. By comparing this estimate with existing estimates of the disk fraction of clusters younger than 10Myrs, our study suggests that the disk fraction of Dolidze 25 is lower than what is expected from its age alone. Even if our results are not conclusive given the intrinsic uncertainty on stellar ages estimated from isochrones fitting to color-magnitude diagrams, we suggest that disk evolution in Dolidze 25 may be impacted by the environment. Given the poor O star population and low stellar density of the cluster, it is more likely that disks dispersal timescale is dictated more by the low metallicity of the cluster rather than external photoevaporation or dynamical encounters.
- ID:
- ivo://CDS.VizieR/II/187A
- Title:
- 30 Doradus OB Associations
- Short Name:
- II/187A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Johnson UBV photometry is presented for 2395 stars in the OB associations of 30 Doradus in the Large Magellanic Cloud. The CCD fields cover an area of 50 square arcminutes in the central region. The entire catalog (exclusive of the dense core cluster R136) is photometrically complete to V=B=18mag and U=17mag, although the completeness magnitudes are fainter for regions with less nebular contamination.
- ID:
- ivo://CDS.VizieR/J/A+A/464/641
- Title:
- Double stars CCD photometry and astrometry. III
- Short Name:
- J/A+A/464/641
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent CCD observations were performed in the period 1998-2004 for a large sample of visual double and multiple stars selected from the Hipparcos Catalogue (Cat. <I/239>) and/or from the Gliese Catalogue of Nearby Stars (Cat. <V/70>). Accurate astrometric and photometric data allowing us to characterise the individual components are provided. These data are compared to Hipparcos data or to data from an older epoch to assess the nature of the observed systems. We simultaneously apply a Moffat-Lorentz profile with a similar shape to all detected components and adjust the profile parameters from which we obtain the relative astrometric position (epoch, position angle, angular separation) as well as differential multi-colour photometry (filters (B)VRI).
- ID:
- ivo://CDS.VizieR/II/234
- Title:
- Draft EIS Colour Catalog
- Short Name:
- II/234
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is a DRAFT multicolour catalogue resulting from the multi- passband ESO Imaging Survey (EIS, see J/A+A/379/740) in the direction of the Chandra Deep Field South (CDF-S), located at RA=03h32m, Dec=-27{deg}48'. The observations were conducted at the ESO/MPG 2.2 m telescope at La Silla using the 8kx8k Wide-Field Imager (WFI).
- ID:
- ivo://CDS.VizieR/J/AJ/158/82
- Title:
- DS Andromedae radial velocity & photometric data
- Short Name:
- J/AJ/158/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Wilson-Devinney program has been used to analyze well-calibrated photometric and new radial velocity data to determine the properties and distance of DS Andromedae, a 1.01 day period, double-lined, totally eclipsing binary system of early-F spectral type and a likely member of the intermediate-age open cluster NGC 752. The determinations of many of the system elements including the distance are robust against modest changes in model assumptions. Third light is present in all passbands at the 10% level. The weighted means of the best-fitting model yield a distance of 477+/-4+/-12 pc, equivalent to (m-M)_0_=8.390+/-0.018+/-0.060 mag, and masses of 1.655+/-0.003+/-0.030 M_Sun_ and 1.087+/-0.005+/-0.040 M_Sun_, radii of 2.086+/-0.003+/-0.013 and 1.255+/-0.005+/-0.012 R_Sun_, and effective temperatures 7056+/-21+/-140 R_Sun_ and 5971+/-33+/-130 K, for components 1 and 2, respectively, where the formal internal uncertainties are followed by conservatively estimated systematic errors. Possible but less satisfactory semidetached models produce more parameter variations and larger mean residuals. The primary star is seen to be at or very close to the main-sequence turnoff at an age of 1.55+/-0.05 Gyr but appears to be too small for its mass, whereas the secondary appears to be too luminous for its temperature and too large for its mass compared to models of single stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/7
- Title:
- dSph satellites of M31. I. Variables in And XIX
- Short Name:
- J/ApJ/779/7
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present B, V time-series photometry of Andromeda XIX (And XIX), the most extended (half-light radius of 6.2') of Andromeda's dwarf spheroidal companions, which we observed with the Large Binocular Cameras at the Large Binocular Telescope. We surveyed a 23'x23' area centered on And XIX and present the deepest color-magnitude diagram (CMD) ever obtained for this galaxy, reaching, at V~26.3mag, about one magnitude below the horizontal branch (HB). The CMD shows a prominent and slightly widened red giant branch, along with a predominantly red HB, which extends to the blue to significantly populate the classical instability strip. We have identified 39 pulsating variable stars, of which 31 are of RR Lyrae type and 8 are Anomalous Cepheids (ACs). Twelve of the RR Lyrae variables and three of the ACs are located within And XIX's half light radius. The average period of the fundamental mode RR Lyrae stars (<P_ab_>{=}0.62days, {sigma}=0.03days) and the period-amplitude diagram qualify And XIX as an Oosterhoff-Intermediate system. From the average luminosity of the RR Lyrae stars (<V(RR)>=25.34mag, {sigma}=0.10mag), we determine a distance modulus of (m-M)_0_=24.52+/-0.23mag in a scale where the distance to the Large Magellanic Cloud (LMC) is 18.5+/-0.1mag. The ACs follow a well-defined Period-Wesenheit (PW) relation that appears to be in very good agreement with the PW relationship defined by the ACs in the LMC.
- ID:
- ivo://CDS.VizieR/J/ApJ/744/150
- Title:
- Dust-obscured galaxies (DOGs) at z=~2
- Short Name:
- J/ApJ/744/150
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Spitzer Space Telescope has identified a population of ultraluminous infrared galaxies (ULIRGs) at z~2 that may play an important role in the evolution of massive galaxies. We measure the stellar masses (M_*_) of two populations of Spitzer-selected ULIRGs that have extremely red R-[24] colors (dust-obscured galaxies, or DOGs) and compare our results with submillimeter-selected galaxies (SMGs). One set of 39 DOGs has a local maximum in their mid-infrared (mid-IR) spectral energy distribution (SED) at rest frame 1.6um associated with stellar emission ("bump DOGs"), while the other set of 51 DOGs have power-law mid-IR SEDs that are typical of obscured active galactic nuclei ("power-law DOGs"). We measure M_*_ by applying Charlot & Bruzual (1991ApJ...367..126C) stellar population synthesis models to broadband photometry in the rest-frame ultraviolet, optical, and near-infrared of each of these populations.
