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18081. zCOSMOS 10K sample group catalog to z=1
ID:
ivo://CDS.VizieR/J/ApJ/697/1842
Title:
zCOSMOS 10K sample group catalog to z=1
Short Name:
J/ApJ/697/1842
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a galaxy group catalog spanning the redshift range 0.1<~z<~1 in the ~1.7deg^2^ COSMOS field, based on the first ~10000 zCOSMOS spectra. The performance of both the Friends-of-Friends (FOF) and Voronoi-Delaunay method (VDM) approaches to group identification has been extensively explored and compared using realistic mock catalogs. We find that the performance improves substantially if groups are found by progressively optimizing the group-finding parameters for successively smaller groups, and that the highest fidelity catalog, in terms of completeness and purity, is obtained by combining the independently created FOF and VDM catalogs. The final completeness and purity of this catalog, both in terms of the groups and of individual members, compares favorably with recent results in the literature. The current group catalog contains 102 groups with N>=5 spectroscopically confirmed members, with a further ~700 groups with 2<=N<=4. Most of the groups can be assigned a velocity dispersion and a dark-matter mass derived from the mock catalogs, with quantifiable uncertainties. The fraction of zCOSMOS galaxies in groups is about 25% at low redshift and decreases toward ~15% at z~0.8. The zCOSMOS group catalog is broadly consistent with that expected from the semianalytic evolution model underlying the mock catalogs.
18082. zCOSMOS 20k sample group catalog to z<~1.2
ID:
ivo://CDS.VizieR/J/ApJ/753/121
Title:
zCOSMOS 20k sample group catalog to z<~1.2
Short Name:
J/ApJ/753/121
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an optical group catalog between 0.1<~z<~1 based on 16500 high-quality spectroscopic redshifts in the completed zCOSMOS-bright survey. The catalog published herein contains 1498 groups in total and 192 groups with more than five observed members. The catalog includes both group properties and the identification of the member galaxies. Based on mock catalogs, the completeness and purity of groups with three and more members should be both about 83% with respect to all groups that should have been detectable within the survey, and more than 75% of the groups should exhibit a one-to-one correspondence to the "real" groups. Particularly at high redshift, there are apparently more galaxies in groups in the COSMOS field than expected from mock catalogs. We detect clear evidence for the growth of cosmic structure over the last seven billion years in the sense that the fraction of galaxies that are found in groups (in volume-limited samples) increases significantly with cosmic time. In the second part of the paper, we develop a method for associating galaxies that only have photo-z to our spectroscopically identified groups. We show that this leads to improved definition of group centers, improved identification of the most massive galaxies in the groups, and improved identification of central and satellite galaxies, where we define the former to be galaxies at the minimum of the gravitational potential wells. Subsamples of centrals and satellites in the groups can be defined with purities up to 80%, while a straight binary classification of all group and non-group galaxies into centrals and satellites achieves purities of 85% and 75%, respectively, for the spectroscopic sample.
18083. zCOSMOS type-2 AGN
ID:
ivo://CDS.VizieR/J/A+A/510/A56
Title:
zCOSMOS type-2 AGN
Short Name:
J/A+A/510/A56
Date:
21 Oct 2021
Publisher:
CDS
Description:
Catalog of type-2 AGN optically selected from the zCOSMOS survey using the diagnostic diagrams. The sample spans the redshift range 0.15<z<0.92 and the luminosity range 10^5.5^L_{sun}_<L([OIII])<10^9.1^L_{sun}_.
18084. z<1 3CR radio galaxies and quasars star formation
ID:
ivo://CDS.VizieR/J/AJ/151/120
Title:
z<1 3CR radio galaxies and quasars star formation
Short Name:
J/AJ/151/120
Date:
16 Dec 2021 13:37:06
Publisher:
CDS
Description:
Using the Herschel Space Observatory we have observed a representative sample of 87 powerful 3CR sources at redshift z<1. The far-infrared (FIR, 70-500 {mu}m) photometry is combined with mid-infrared (MIR) photometry from the Wide-Field Infrared Survey Explorer and cataloged data to analyze the complete spectral energy distributions (SEDs) of each object from optical to radio wavelength. To disentangle the contributions of different components, the SEDs are fitted with a set of templates to derive the luminosities of host galaxy starlight, dust torus emission powered by active galactic nuclei (AGNs), and cool dust heated by stars. The level of emission from relativistic jets is also estimated to isolate the thermal host galaxy contribution. The new data are in line with the orientation-based unification of high-excitation radio-loud AGN, in that the dust torus becomes optically thin longwards of 30 {mu}m. The low-excitation radio galaxies and the MIR-weak sources represent an MIR- and FIR-faint AGN population that is different from the high-excitation MIR-bright objects; it remains an open question whether they are at a later evolutionary state or an intrinsically different population. The derived luminosities for host starlight and dust heated by star formation are converted to stellar masses and star-formation rates (SFR). The host-normalized SFR of the bulk of the 3CR sources is low when compared to other galaxy populations at the same epoch. Estimates of the dust mass yield a 1-100 times lower dust/stellar mass ratio than for the Milky Way, which indicates that these 3CR hosts have very low levels of interstellar matter and explains the low level of star formation. Less than 10% of the 3CR sources show levels of star formation above those of the main sequence of star-forming galaxies.
18085. z>3 damped Ly{alpha} absorption systems
ID:
ivo://CDS.VizieR/J/ApJ/543/552
Title:
z>3 damped Ly{alpha} absorption systems
Short Name:
J/ApJ/543/552
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have completed spectroscopic observations using LRIS on the Keck 1 telescope of 30 very high redshift quasars, 11 selected for the presence of damped Ly{alpha} absorption systems and 19 with redshifts z>3.5 not previously surveyed for absorption systems. We have surveyed an additional 10 QSOs with the Lick 120" and the Anglo-Australian Telescope. We have combined these with previous data, resulting in a statistical sample of 646 QSOs and 85 damped Ly{alpha} absorbers with column densities N_HI_>=2 10^20^atoms/cm^2^ covering the redshift range 0.008<=z<=4.694. Four main features of how the neutral gas in the universe evolves with redshift are evident from these data.
18086. ZDI maps of five young solar-type stars
ID:
ivo://CDS.VizieR/J/A+A/659/A71
Title:
ZDI maps of five young solar-type stars
Short Name:
J/A+A/659/A71
Date:
09 Mar 2022 16:47:36
Publisher:
CDS
Description:
The magnetic activity of the Sun changes with the solar cycle. Similar cycles are found in other stars as well, but their details are not known to a similar degree. Characterising stellar magnetic cycles is important for the understanding of the stellar and solar dynamos that are driving the magnetic activity. We present spectropolarimetric observations of five young, solar-type stars and compare them to previous observations, with the aim to identify and characterise stellar equivalents of the solar cycle. We use Zeeman-Doppler imaging (ZDI) to map the surface magnetic field and brightness of our targets. The magnetic field is decomposed into spherical harmonic expansions, from which we report the strengths of the axisymmetric versus non-axisymmetric and poloidal versus toroidal components, and we compare them to the Rossby numbers of the stars. We present five new ZDI maps of young, solar-type stars from December 2017. Of special interest is the case of V1358 Ori, which had gone through a polarity reversal between our observations and earlier ones. A less evident polarity reversal might also have occurred in HD 35296. There is a preference for a more axisymmetric field, and possibly a more toroidal field, for the more active stars with lower Rossby number, but a larger sample should be studied to draw any strong conclusions from this. For most of the individual stars, the amounts of toroidal and poloidal field have stayed on levels similar to those in earlier observations. We find evidence for a magnetic polarity reversal having occurred in V1358 Ori. An interesting target for future observations is {chi}^1^ Ori, which may have a short magnetic cycle of a few years. The correlation between the brightness maps and the magnetic field is mostly poor, which could indicate the presence of small-scale magnetic features of different polarities that cancel one another out and are thus not resolved in our maps.
18087. Zelenchuk survey 9h<=RA<=12h, 0<=DE<=8{deg}
ID:
ivo://CDS.VizieR/J/other/BSAO/45.136
Title:
Zelenchuk survey 9h<=RA<=12h, 0<=DE<=8{deg}
Short Name:
J/other/BSAO/45.
Date:
21 Oct 2021
Publisher:
CDS
Description:
Optical identification of Zelenchuk Survey radio sources at 3.9GHz from 9h to 12h in right ascension and between 0{deg} and 8{deg} in declination is reported in this paper. Some optical characteristics of identified radio sources are presented in the table.
18088. ZENS: galaxies in groups along the cosmic web. I.
ID:
ivo://CDS.VizieR/J/ApJ/776/71
Title:
ZENS: galaxies in groups along the cosmic web. I.
Short Name:
J/ApJ/776/71
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Zurich Environmental Study (ZENS) is based on a sample of ~1500 galaxy members of 141 groups in the mass range ~10^12.5-14.5^M_{sun}_ within the narrow redshift range 0.05<z<0.0585. ZENS adopts novel approaches, described here, to quantify four different galactic environments, namely: (1) the mass of the host group halo; (2) the projected halo-centric distance; (3) the rank of galaxies as central or satellites within their group halos; and (4) the filamentary large-scale structure density. No self-consistent identification of a central galaxy is found in ~40% of <10^13.5^M_{sun}_ groups, from which we estimate that ~15% of groups at these masses are dynamically unrelaxed systems. Central galaxies in relaxed and unrelaxed groups generally have similar properties, suggesting that centrals are regulated by their mass and not by their environment. Centrals in relaxed groups have, however, ~30% larger sizes than in unrelaxed groups, possibly due to accretion of small satellites in virialized group halos. At M>10^10^M_{sun}_, satellite galaxies in relaxed and unrelaxed groups have similar size, color, and (specific) star formation rate distributions; at lower galaxy masses, satellites are marginally redder in relaxed relative to unrelaxed groups, suggesting quenching of star formation in low-mass satellites by physical processes active in relaxed halos. Overall, relaxed and unrelaxed groups show similar stellar mass populations, likely indicating similar stellar mass conversion efficiencies.
18089. ZFIRE v1.0 data release
ID:
ivo://CDS.VizieR/J/ApJ/828/21
Title:
ZFIRE v1.0 data release
Short Name:
J/ApJ/828/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an overview and the first data release of ZFIRE, a spectroscopic redshift survey of star-forming galaxies that utilizes the MOSFIRE instrument on Keck-I to study galaxy properties in rich environments at 1.5<z<2.5. ZFIRE measures accurate spectroscopic redshifts and basic galaxy properties derived from multiple emission lines. The galaxies are selected from a stellar mass limited sample based on deep near infrared imaging (K_AB_<25) and precise photometric redshifts from the ZFOURGE and UKIDSS surveys as well as grism redshifts from 3DHST. Between 2013 and 2015, ZFIRE has observed the COSMOS and UDS legacy fields over 13 nights and has obtained 211 galaxy redshifts over 1.57<z<2.66 from a combination of nebular emission lines (such as H{alpha}, [NII], H{beta}, [OII], [OIII], and [SII]) observed at 1-2{mu}m. Based on our medium-band near infrared photometry, we are able to spectrophotometrically flux calibrate our spectra to ~10% accuracy. ZFIRE reaches 5{sigma} emission line flux limits of ~3x10^-18^erg/s/cm^2^ with a resolving power of R=3500 and reaches masses down to ~10^9^M_{sun}_. We confirm that the primary input survey, ZFOURGE, has produced photometric redshifts for star-forming galaxies (including highly attenuated ones) accurate to {Delta}z/(1+z_spec_)=0.015 with 0.7% outliers. We measure a slight redshift bias of <0.001, and we note that the redshift bias tends to be larger at higher masses. We also examine the role of redshift on the derivation of rest-frame colors and stellar population parameters from SED fitting techniques. The ZFIRE survey extends spectroscopically confirmed z~2 samples across a richer range of environments, here we make available the first public release of the data for use by the community.
18090. ZFOURGE catalogue of AGN candidates
ID:
ivo://CDS.VizieR/J/MNRAS/457/629
Title:
ZFOURGE catalogue of AGN candidates
Short Name:
J/MNRAS/457/629
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate active galactic nuclei (AGN) candidates within the FourStar Galaxy Evolution Survey (ZFOURGE) to determine the impact they have on star formation in their host galaxies. We first identify a population of radio, X-ray, and infrared-selected AGN by cross-matching the deep Ks-band imaging of ZFOURGE with overlapping multiwavelength data. From this, we construct a mass-complete (log(M*/M_{sun}_)>=9.75), AGN luminosity limited sample of 235 AGN hosts over z=0.2-3.2. We compare the rest-frame U-V versus V-J (UVJ) colours and specific star formation rates (sSFRs) of the AGN hosts to a mass-matched control sample of inactive (non-AGN) galaxies. UVJ diagnostics reveal AGN tend to be hosted in a lower fraction of quiescent galaxies and a higher fraction of dusty galaxies than the control sample. Using 160{mu}m Herschel PACS data, we find the mean specific star formation rate of AGN hosts to be elevated by 0.34-/-0.07dex with respect to the control sample across all redshifts. This offset is primarily driven by infrared-selected AGN, where the mean sSFR is found to be elevated by as much as a factor of ~5. The remaining population, comprised predominantly of X-ray AGN hosts, is found mostly consistent with inactive galaxies, exhibiting only a marginal elevation. We discuss scenarios that may explain these findings and postulate that AGN are less likely to be a dominant mechanism for moderating galaxy growth via quenching than has previously been suggested.

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