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41. Chandra X-ray sources of NGC 1399
ID:
ivo://CDS.VizieR/J/ApJ/736/90
Title:
Chandra X-ray sources of NGC 1399
Short Name:
J/ApJ/736/90
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a wide-field study of the globular cluster (GC)/low-mass X-ray binary (LMXB) connection in the giant elliptical NGC 1399. The large field of view of the Advanced Camera for Surveys/WFC, combined with Hubble Space Telescope and Chandra high resolution, allow us to constrain the LMXB formation scenarios in elliptical galaxies. We confirm that NGC 1399 has the highest LMXB fraction in GCs of all nearby elliptical galaxies studied so far, even though the exact value depends on galactocentric distance due to the interplay of a differential GC versus galaxy light distribution and the GC color dependence. In fact, LMXBs are preferentially hosted by bright, red GCs out to >5R_eff_ of the galaxy light. The finding that GCs hosting LMXBs follow the radial distribution of their parent GC population argues against the hypothesis that the external dynamical influence of the galaxy affects the LMXB formation in GCs. On the other hand, field-LMXBs closely match the host galaxy light, thus indicating that they are originally formed in situ and not inside GCs. We measure GC structural parameters, finding that the LMXB formation likelihood is influenced independently by mass, metallicity, and GC structural parameters. In particular, the GC central density plays a major role in predicting which GCs host accreting binaries. Finally, our analysis shows that LMXBs in GCs are marginally brighter than those in the field, and in particular the only color-confirmed GC with L_X_>10^39^erg/s shows no variability, which may indicate a superposition of multiple LMXBs in these systems.
42. Cl 0024+16 and MS 0451-03 spectrophotometry
ID:
ivo://CDS.VizieR/J/ApJ/671/1503
Title:
Cl 0024+16 and MS 0451-03 spectrophotometry
Short Name:
J/ApJ/671/1503
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new results from our comparative survey of two massive, intermediate-redshift galaxy clusters, Cl 0024+17 (z=0.39) and MS 0451-03 (z=0.54). Combining optical and UV imaging with spectroscopy of member galaxies, we identify and study several key classes of "transition objects" whose stellar populations or dynamical states indicate a recent change in morphology and star formation rate. For the first time, we have been able to conclusively identify spiral galaxies in the process of transforming into S0 galaxies. This has been accomplished by locating both spirals whose star formation is being quenched and their eventual successors, the recently created S0s.
43. CLASH. Photometric + photo-z catalog
ID:
ivo://CDS.VizieR/J/A+A/562/A86
Title:
CLASH. Photometric + photo-z catalog
Short Name:
J/A+A/562/A86
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Cluster Lensing And Supernovae survey with Hubble (CLASH) is a Hubble Space Telescope (HST) Multi-Cycle Treasury programme that observes 25 massive galaxy clusters, 20 of which were X-ray-selected to preferably choose dynamically relaxed clusters, and 5 additional "high magnification" clusters, which were selected based on their optical lensing properties. CLASH aims to study the dark matter distribution of the clusters and find magnified high-redshift galaxies behind them. CLASH observations were carried out in 16 bands from UV to NIR to derive accurate and reliable estimates of photometric redshifts. We present the CLASH photometric redshifts using 16 HST bands and study the photometric redshift accuracy including a detailed comparison between photometric and spectroscopic redshifts for the strong lensing arcs using the measurements from the cluster MACSJ1206.2-0847.
44. CLASH sources for MACS1149.6+2223
ID:
ivo://CDS.VizieR/J/ApJS/199/25
Title:
CLASH sources for MACS1149.6+2223
Short Name:
J/ApJS/199/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Cluster Lensing And Supernova survey with Hubble (CLASH) is a 524-orbit Multi-Cycle Treasury Program to use the gravitational lensing properties of 25 galaxy clusters to accurately constrain their mass distributions. The survey, described in detail in this paper, will definitively establish the degree of concentration of dark matter in the cluster cores, a key prediction of structure formation models. The CLASH cluster sample is larger and less biased than current samples of space-based imaging studies of clusters to similar depth, as we have minimized lensing-based selection that favors systems with overly dense cores. Specifically, 20 CLASH clusters are solely X-ray selected. The X-ray-selected clusters are massive (kT>5keV) and, in most cases, dynamically relaxed. Five additional clusters are included for their lensing strength ({theta}_Ein_>35" at z_s_=2) to optimize the likelihood of finding highly magnified high-z (z>7) galaxies. A total of 16 broadband filters, spanning the near-UV to near-IR, are employed for each 20-orbit campaign on each cluster. These data are used to measure precise ({sigma}_z_~0.02(1+z)) photometric redshifts for newly discovered arcs. Observations of each cluster are spread over eight epochs to enable a search for Type Ia supernovae at z>1 to improve constraints on the time dependence of the dark energy equation of state and the evolution of supernovae. We present newly re-derived X-ray luminosities, temperatures, and Fe abundances for the CLASH clusters as well as a representative source list for MACS1149.6+2223 (z=0.544).
45. CLEAR. II. SFRs of quiescent galaxies
ID:
ivo://CDS.VizieR/J/ApJ/898/171
Title:
CLEAR. II. SFRs of quiescent galaxies
Short Name:
J/ApJ/898/171
Date:
16 Mar 2022 00:57:30
Publisher:
CDS
Description:
The origin of the correlations between mass, morphology, quenched fraction, and formation history in galaxies is difficult to define, primarily due to the uncertainties in galaxy star formation histories (SFHs). SFHs are better constrained for higher redshift galaxies, observed closer to their formation and quenching epochs. Here we use "nonparametric" SFHs and a nested sampling method to derive constraints on the formation and quenching timescales of quiescent galaxies at 0.7<z<2.5. We model deep HST grism spectroscopy and photometry from the CLEAR (CANDELS Ly{alpha} Emission at Reionization) survey. The galaxy formation redshifts, z50 (defined as the point where they had formed 50% of their stellar mass) range from z_50_~2 (shortly prior to the observed epoch) up to z_50_~5-8. We find that early formation redshifts are correlated with high stellar-mass surface densities, log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25, where {Sigma}_1_ is the stellar mass within 1pkpc (proper kpc). Quiescent galaxies with the highest stellar-mass surface density, log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25, show a minimum formation redshift: all such objects in our sample have z_50_>2.9. Quiescent galaxies with lower surface density, log{Sigma}_1_/(M_{sun}_kpc^-2^)=9.5-10.25, show a range of formation epochs (z_50_~1.5-8), implying these galaxies experienced a range of formation and assembly histories. We argue that the surface density threshold log{Sigma}_1_/(M_{sun}_kpc^-2^)>10.25 uniquely identifies galaxies that formed in the first few Gyr after the big bang, and we discuss the implications this has for galaxy formation models.
46. Clumpy galaxies in CANDELS. II. 0.5<=z<3.0
ID:
ivo://CDS.VizieR/J/ApJ/853/108
Title:
Clumpy galaxies in CANDELS. II. 0.5<=z<3.0
Short Name:
J/ApJ/853/108
Date:
21 Oct 2021
Publisher:
CDS
Description:
Studying giant star-forming clumps in distant galaxies is important to understand galaxy formation and evolution. At present, however, observers and theorists have not reached a consensus on whether the observed "clumps" in distant galaxies are the same phenomenon that is seen in simulations. In this paper, as a step to establish a benchmark of direct comparisons between observations and theories, we publish a sample of clumps constructed to represent the commonly observed "clumps" in the literature. This sample contains 3193 clumps detected from 1270 galaxies at 0.5<=z<3.0. The clumps are detected from rest-frame UV images, as described in our previous paper. Their physical properties (e.g., rest-frame color, stellar mass (M*), star formation rate (SFR), age, and dust extinction) are measured by fitting the spectral energy distribution (SED) to synthetic stellar population models. We carefully test the procedures of measuring clump properties, especially the method of subtracting background fluxes from the diffuse component of galaxies. With our fiducial background subtraction, we find a radial clump U-V color variation, where clumps close to galactic centers are redder than those in outskirts. The slope of the color gradient (clump color as a function of their galactocentric distance scaled by the semimajor axis of galaxies) changes with redshift and M* of the host galaxies: at a fixed M*, the slope becomes steeper toward low redshift, and at a fixed redshift, it becomes slightly steeper with M*. Based on our SED fitting, this observed color gradient can be explained by a combination of a negative age gradient, a negative E(B-V) gradient, and a positive specific SFR gradient of the clumps. We also find that the color gradients of clumps are steeper than those of intra-clump regions. Correspondingly, the radial gradients of the derived physical properties of clumps are different from those of the diffuse component or intra-clump regions.
47. 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.
48. Column densities of CGM absorption lines
ID:
ivo://CDS.VizieR/J/ApJ/883/78
Title:
Column densities of CGM absorption lines
Short Name:
J/ApJ/883/78
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the geometric distribution of gas metallicities in the circumgalactic medium (CGM) around 47, z<0.7 galaxies from the "Multiphase Galaxy Halos" Survey. Using a combination of quasar spectra from Hubble Space Telescope (HST)/COS and from Keck/HIRES or Very Large Telescope/UVES, we measure column densities of, or determine limits on, CGM absorption lines. We then use a Markov Chain Monte Carlo approach with Cloudy to estimate the metallicity of cool (T~10^4^K) CGM gas. We also use HST images to determine host-galaxy inclination and quasar-galaxy azimuthal angles. Our sample spans a HI column density range of 13.8cm^-2^<logN_HI_<19.9cm^-2^. We find (1) while the metallicity distribution appears bimodal, a Hartigan dip test cannot rule out a unimodal distribution (0.4{sigma}). (2) CGM metallicities are independent of halo mass, spanning three orders of magnitude at a fixed halo mass. (3) The CGM metallicity does not depend on the galaxy azimuthal and inclination angles regardless of HI column density, impact parameter, and galaxy color. (4) The ionization parameter does not depend on azimuthal angle. We suggest that the partial Lyman limit metallicity bimodality is not driven by a spatial azimuthal bimodality. Our results are consistent with simulations where the CGM is complex and outflowing, accreting, and recycled gas are well-homogenized at z<0.7. The presence of low-metallicity gas at all orientations suggests that cold streams of accreting filaments are not necessarily aligned with the galaxy plane at low redshifts or intergalactic transfer may dominate. Finally, our results support simulations showing that strong metal absorption can mask the presence of low-metallicity gas in integrated line-of-sight CGM metallicities.
49. Compact clusters in LMC catalogue of stars
ID:
ivo://CDS.VizieR/J/A+A/503/469
Title:
Compact clusters in LMC catalogue of stars
Short Name:
J/A+A/503/469
Date:
21 Oct 2021
Publisher:
CDS
Description:
The LMC is an ideal environment for studying stellar MFs, because it contains a large population of compact clusters at different evolutionary stages. We aim to obtain constraints on the initial MFs (IMFs) of our sample clusters on the basis of their present-day MFs, combined with our understanding of their dynamical and photometric evolution. We use Hubble Space Telescope photometry for six rich, compact star clusters in the Large Magellanic Cloud (LMC), with ages ranging from 0.01 to 1.0Gyr, to derive the clusters' stellar mass functions (MFs) at their half-mass radii.
50. Compact star clusters in M81
ID:
ivo://CDS.VizieR/J/MNRAS/405/1293
Title:
Compact star clusters in M81
Short Name:
J/MNRAS/405/1293
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the population of compact star clusters (CSCs) in M81, using the Hubble Space Telescope/Advanced Camera for Surveys (ACS) images in the filters F435W, F606W and F814W covering, for the first time, the entire optical extent of the galaxy. Our sample contains 435 clusters of full width at half-maximum less than 10 ACS pixels (9pc). The sample shows the presence of two cluster populations, a blue group of 263 objects brighter than B=22mag, and a red group of 172 objects, brighter than B=24mag. On the basis of analysis of colour-magnitude diagrams and making use of simple stellar population models,

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