Search

Start Over Capability Type Simple Cone Search
3091. Color-magnitude relations of galaxies in CDFs
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.
3092. Color-metallicity relations. II. M87 GCs
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.
3093. Color-metallicity relations of GCs. X. M87 spec.
ID:
ivo://CDS.VizieR/J/ApJS/256/29
Title:
Color-metallicity relations of GCs. X. M87 spec.
Short Name:
J/ApJS/256/29
Date:
02 Mar 2022 00:28:26
Publisher:
CDS
Description:
We obtained spectra of some 140 globular clusters (GCs) associated with the Virgo central cD galaxy M87 with the Subaru/FOCAS MOS mode. The fundamental properties of GCs such as age, metallicity, and {alpha}-element abundance are investigated by using simple stellar population models. It is confirmed that the majority of M87 GCs are as old as, more metal-rich than, and more enhanced in {alpha}-elements than the Milky Way GCs. Our high-quality, homogeneous data set enables us to test the theoretical prediction of inflected color-metallicity relations (CMRs). The nonlinear-CMR hypothesis entails an alternative explanation for the widely observed GC color bimodality, in which even a unimodal metallicity spread yields a bimodal color distribution by virtue of nonlinear metallicity-to-color conversion. The newly derived CMRs of old, high-signal-to-noise-ratio GCs in M87 (the V-I CMR of 83 GCs and the M-T2 CMR of 78 GCs) corroborate the presence of the significant inflection. Furthermore, from a combined catalog with the previous study on M87 GC spectroscopy, we find that a total of 185 old GCs exhibit a broad, unimodal metallicity distribution. The results corroborate the nonlinear-CMR interpretation of the GC color bimodality, shedding further light on theories of galaxy formation.
3094. Color panorama image of the Milky Way
ID:
ivo://CDS.VizieR/J/PASP/121/1180
Title:
Color panorama image of the Milky Way
Short Name:
J/PASP/121/1180
Date:
21 Oct 2021
Publisher:
CDS
Description:
This article describes the assembly of an optical (RGB) all-sky mosaic image with an image scale of 36"/pix, a limiting magnitude of approximately 14mag, and an 18 bit dynamic range. Using a portable low-cost CCD camera system, 70 fields (each covering 40{deg}x27{deg}) were imaged over a time span of 22 months from dark-sky locations in South Africa, Texas, and Michigan. The fields were photometrically calibrated against standard catalog stars. Using sky background data from the Pioneer 10 and 11 space probes, gradients resulting from artificial light pollution, airglow, and zodiacal light were eliminated, while the large-scale galactic and extragalactic background resulting from unresolved sources was preserved. The 648 megapixel image is a valuable educational tool, being able to fully utilize the resolution and dynamic range of modern full-dome planetarium projection systems.
3095. Color-period diagram for M48 (NGC2548)
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.
3096. 13-color photometry of 1380 bright stars
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.
3097. Colors and extinction across the disk of M31
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.
3098. Colors and kinematics of SDSS L dwarfs
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.
3099. Colour and spectral index from the SLUGGS survey
ID:
ivo://CDS.VizieR/J/MNRAS/446/369
Title:
Colour and spectral index from the SLUGGS survey
Short Name:
J/MNRAS/446/369
Date:
21 Oct 2021
Publisher:
CDS
Description:
As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ~90 {AA}^-1^. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the H{alpha} and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and differences in the calcium triplet-colour relation from galaxy to galaxy. We interpret this as strong evidence for variations in the globular cluster colour-metallicity relation between galaxies. Two possible explanations for the colour-metallicity relation variations are that the average ages of globular clusters vary from galaxy to galaxy or that the average abundances of light elements (i.e. He, C, N and O) differ between galaxies. Stacking spectra by magnitude, we see that the colours become redder and metal line indices stronger with brighter magnitudes. These trends are consistent with the previously reported `blue tilts' being mass-metallicity relations.
3100. Colour indices of selected OB stars
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.

Limit your search

more »

more »

more »

more »

more »

more »