- ID:
- ivo://CDS.VizieR/J/ApJS/142/153
- Title:
- Distant galaxy clusters photometry
- Short Name:
- J/ApJS/142/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present optical and near-infrared photometry of 45 clusters of galaxies at 0.1<z<1.3. Galaxy catalogs in each cluster were defined at the longest wavelength available, generally the K band, down to approximately 2mag below M*. We include finding chart images of the band used for catalog definition. The photometry has been used in previously published papers to examine the origin and evolution of galaxies in distant clusters. Beginning in 1991, we sought to make use of the advent of relatively large format near-IR detectors to study the galaxy populations of distant clusters. We collected imaging data in both the near-IR and the optical on a large sample of clusters drawn from several samples. These data were analyzed and detailed results were presented on the evolution of early-type galaxies at moderate redshifts in Stanford, Eisenhardt, & Dickinson (1995ApJ...450..512S, 1998ApJ...492..461S), on the evolution of the K-band luminosity function in De Propris et al. (1999AJ....118..719D), on the Butcher-Oemler effect in K-selected galaxy samples in De Propris et al. (2003, ApJ, submitted), and on the evolution of early-type galaxies in high-redshift clusters in Holden et al. (2003, ApJ, in press). So far the photometry for these various studies has been published for only two clusters, Abell 370 and Abell 851 in Stanford et al. (1995ApJ...450..512S). In this paper, we present the photometry on the other 43 clusters used in our published work on distant clusters.
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- ID:
- ivo://CDS.VizieR/J/PASP/105/1465
- Title:
- Distant OB Stars in the Galaxy
- Short Name:
- J/PASP/105/1465
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Distances and reddenings have been computed from UBVbeta photometry for 1044 stars in the Stephenson and Sanduleak (1971) "Catalog of Luminous Stars in the Southern Milky Way".
- 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.
- 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/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.
- ID:
- ivo://CDS.VizieR/J/AJ/115/1856
- Title:
- Dwarf Cepheids in Carina
- Short Name:
- J/AJ/115/1856
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have discovered 20 dwarf Cepheids (DCs) in the Carina dwarf spheroidal galaxy from an analysis of individual CCD images obtained for a deep photometric study of the system. These short-period pulsating variable stars are by far the most distant (~100kpc) and faintest (V~23.0) DCs known. The Carina DCs obey a well-defined period-luminosity relation, allowing us to readily distinguish between overtone and fundamental pulsators in nearly every case. Unlike RR Lyrae stars, the pulsation mode turns out to be uncorrelated with light-curve shape, and the overtone pulsators do not tend toward shorter periods compared with the fundamental pulsators. Using the period-luminosity relations from Nemec, Nemec, & Lutz (1994, Cat. <J/AJ/108/222> and McNamara (1995AJ....109.1751M), we derive (m-M)_0_=20.06+/-0.12, for E(B-V)=0.025 and [Fe/H]=-2.0, in good agreement with recent, independent estimates of the distance/reddening of Carina. The error reflects the uncertainties in the DC distance scale, and in the metallicity and reddening of Carina. The frequency of DCs among upper-main-sequence stars in Carina is approximately 3%. The ratio of dwarf Cepheids to RR Lyrae stars in Carina is 0.13+/-0.10, though this result is highly sensitive to the star formation history of Carina and the evolution of the horizontal branch.
