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- ID:
- ivo://CDS.VizieR/J/ApJ/500/714
- Title:
- Color-magnitude relation in CL 1358+62
- Short Name:
- J/ApJ/500/714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a large, multicolor mosaic of HST WFPC2 images to measure the colors and morphologies of 194 spectroscopically confirmed members of the rich galaxy cluster CL 1358+62 at z=0.33. We study the color-magnitude (CM) relation as a function of radius in the cluster to a limit of 4.6' from the center, equivalent to 1.6h^-1^_50_Mpc. The intrinsic scatter in the rest-frame B-V CM relation of the elliptical galaxies is very small, ~0.022mag. The CM relation of the ellipticals does not depend significantly on the distance from the cluster center. In contrast, the CM relation for the S0 galaxies does depend on radius: the S0's in the core follow a CM relation similar to that of the ellipticals, but at large radii (R>0.7h^-1^_50_Mpc) the S0's are systematically bluer and the scatter in the CM relation approximately doubles, to ~0.043mag. The blueing of the S0's at large radii is significant at the 95% confidence level. These results imply that the S0 galaxies in the outer parts of the cluster have formed stars more recently than the S0's in the inner parts.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/368
- Title:
- Color-magnitude relations of galaxies in CDFs
- Short Name:
- J/ApJ/720/368
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend color-magnitude relations for moderate-luminosity X-ray active galactic nucleus (AGN) hosts and non-AGN galaxies through the galaxy formation epoch (z~1-4) in the Chandra Deep Field-North and Chandra Deep Field-South (CDF-N and CDF-S, respectively; jointly CDFs) surveys. This study was enabled by the deepest available X-ray data from the 2Ms CDF surveys as well as complementary ultradeep multiwavelength data in these regions. We utilized analyses of color-magnitude diagrams (CMDs) to assess the role of moderate-luminosity AGNs in galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/149
- Title:
- Color-metallicity relations. II. M87 GCs
- Short Name:
- J/ApJ/743/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We here propose a new photometric technique to probe the possible nonlinear nature of globular clusters (GCs) color-metallicity relations (CMRs). In essence, a color distribution of GCs is a "projected" distribution of their metallicities. Since the form of CMRs hinges on which color is used, the shape of color distributions varies depending significantly on the colors. Among other optical colors, the u-band related colors (e.g., u-g and u-z) are theoretically predicted to exhibit significantly less inflected CMRs than other preferred CMRs (e.g., for g-z). As a case study, we performed the Hubble Space Telescope (HST)/WFPC2 archival u-band photometry for the M87 (NGC 4486) GC system with confirmed color bimodality. We show that the u-band color distributions are significantly different from that of g-z and consistent with our model predictions. With more u-band measurements, this method will support or rule out the nonlinear CMR scenario for the origin of GC color bimodality with high confidence.
- ID:
- ivo://CDS.VizieR/J/A+A/583/A73
- Title:
- Color-period diagram for M48 (NGC2548)
- Short Name:
- J/A+A/583/A73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotation periods are increasingly being used to derive ages for cool single field stars. Such ages are based on an empirical understanding of how cool stars spin down, acquired by constructing color-period diagrams (CPDs) for a series of open clusters. Our main aims here are to construct a CPD for M48, to compare this with other clusters of similar age to check for consistency, and to derive a rotational age for M48 using gyrochronology. We monitored M48 photometrically for over 2months with AIP's STELLA.I 1.2m telescope and the WiFSIP 4K imager in Tenerife. Light curves with 3mmag precision for bright (V~14mag) stars were produced and then analysed to provide rotation periods. A cluster CPD has then been constructed. We report 62 rotation periods for cool stars in M48. The CPD displays a clear slow/I-sequence of rotating stars, similar to those seen in the 625Myr-old Hyades and 590Myr-old Praesepe clusters, and below both, confirming that M48 is younger. A similar comparison with the 250Myr-old M34 cluster shows that M48 is older and does not possess any fast/C-sequence G or early K stars like those in M34, although relatively fast rotators do seem to be present among the late-K and M stars. A more detailed comparison of the CPD with rotational evolution models shows that the cluster stars have a mean age of 450Myr, and its (rotating) stars can be individually dated to +/-117Myr (26%). Much of this uncertainty stems from intrinsic astrophysical spread in initial periods, and almost all stars are consistent with a single age of 450Myr. The gyro-age of M48 as a whole is 450+/-50Myr, in agreement with the previously determined isochrone age of 400+/-100Myr.
- ID:
- ivo://CDS.VizieR/II/84
- Title:
- 13-color photometry of 1380 bright stars
- Short Name:
- II/84
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue contains observations of essentially all stars brighter than fifth visual magnitude north of declination -20 degrees and brighter than fourth visual magnitude south of declination -20 degrees, in the 13-color medium-narrow-band photometric system.
- ID:
- ivo://CDS.VizieR/J/A+A/507/283
- Title:
- Colors and extinction across the disk of M31
- Short Name:
- J/A+A/507/283
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a study of the dust properties in M31. We analyzed Spitzer Space Telescope, GALEX, and SDSS images constraining some basic properties of the dust in M31: (i) the mass of the dust; (ii) the mean intensity of the radiation field heating the dust; (iii) the abundance of Polycyclic Aromatic Hydrocarbon (PAH) particles. We also studied which stellar populations are most likely responsible for the dust heating in M31 analyzing optical and infrared colors and comparing our observations with models which account for the age-dependent dust heating. We found that in most of the regions analyzed stars at least a few Gyr old are the major dust heaters. We then derived the extinction map across the disk of M31.
- ID:
- ivo://CDS.VizieR/J/AJ/139/1808
- Title:
- Colors and kinematics of SDSS L dwarfs
- Short Name:
- J/AJ/139/1808
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a sample of 484 L dwarfs, 210 of which are newly discovered from the Sloan Digital Sky Survey (SDSS) Data Release 7 spectroscopic database. We combine this sample with known L dwarfs to investigate their izJHKS colors. We present photometric distance relations based on i-z and i-J colors and derive distances to our L dwarf sample. We combine the distances with SDSS/2MASS proper motions in order to examine the tangential velocities.
- ID:
- ivo://CDS.VizieR/J/AN/333/60
- Title:
- Colour indices of selected OB stars
- Short Name:
- J/AN/333/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have applied the method of investigating extinction curves using statistically meaningful samples that was proposed by us 25 years ago. The extensive data sets of the ANS (Astronomical Netherlands Satellite) and 2MASS (Two Micron All Sky Survey) were used, together with UBV photometry to create average extinction curves for samples of OB stars. Our results demonstrate that in the vast majority of cases the extinction curves are very close to the mean galactic extinction curve. Only a few objects were found to be obviously discrepant from the average. The latter phenomenon may be related to nitrogen chemistry in translucent interstellar clouds.
- ID:
- ivo://CDS.VizieR/J/A+AS/102/397
- Title:
- Colour magnitude diagram of M13
- Short Name:
- J/A+AS/102/397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Two overlapping regions of M13 were observed on April 24, 1989 at the Loiano Observatory with a CDCD camera. A Colour-Magnitude diagram down to the main sequence was derived, as a preliminary search for the blue Horizontal Branch stars in this cluster.
