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3351. COSMOS Cassata Morphology Catalog
ID:
ivo://irsa.ipac/COSMOS/Catalog/COSMOSMorphCas
Title:
COSMOS Cassata Morphology Catalog
Short Name:
COSMOSMorphCas
Date:
01 Oct 2018 20:27:21
Publisher:
NASA/IPAC Infrared Science Archive
Description:
COSMOS is an astronomical survey designed to probe the formation and evolution of galaxies as a function of cosmic time (redshift) and large scale structural environment. The survey covers a 2 square degree equatorial field with imaging by most of the major space-based telescopes (Hubble, Spitzer, GALEX, XMM, Chandra) and a number of large ground based telescopes (Subaru, VLA, ESO-VLT, UKIRT, NOAO, CFHT, and others). Over 2 million galaxies are detected, spanning 75% of the age of the universe. The COSMOS Cassata Morphology Catalog includes concentration, asymmetry, gini, and M20 measurements within the Petrosian radius. The morphological parameters are combined to classify galaxies as early-types, disks and irregulars.
3352. COSMOS2015 Catalog
ID:
ivo://irsa.ipac/COSMOS/Catalog/COSMOS2015
Title:
COSMOS2015 Catalog
Short Name:
COSMOS2015
Date:
10 May 2021 23:47:23
Publisher:
NASA/IPAC Infrared Science Archive
Description:
The COSMOS2015 catalogue contains precise photometric red-shifts and stellar masses for more than half a million objects over the 2 deg^2 COSMOS field. Including YJHKs images from the UltraVISTA-DR2 survey, Y-band from Subaru/Hyper-Suprime-Cam and infrared data from SPLASH Spitzer Legacy program, this near-infrared selected catalogue is highly optimised for the study of galaxy evolution and environments in the early Universe.
3353. COSMOS2020 Classic Catalog
ID:
ivo://irsa.ipac/COSMOS/Catalog/COSMOS2020C
Title:
COSMOS2020 Classic Catalog
Short Name:
COSMOS2020C
Date:
06 Apr 2023 23:18:13
Publisher:
NASA/IPAC Infrared Science Archive
Description:
In these catalogues, source detection and multi-wavelength photometry is performed for 1.7 million sources in the 2 square degree COSMOS field. Approximately 966,000 of these sources are measured with all available broad-band data using both traditional aperture photometry and a new profile-fitting photometric tool, The Farmer, developed by the COSMOS team. Photometric redshifts are computed for all sources in each catalogue using two independent photometric redshift codes, LePhare and EAZY. At i < 21, sources have sub-percent photometric redshift precision and even the faintest sources at 25 < i < 27 reach a photometric redshift accuracy of 5%.
3354. COSMOS2015 dataset machine learning photo-z
ID:
ivo://CDS.VizieR/J/MNRAS/507/5034
Title:
COSMOS2015 dataset machine learning photo-z
Short Name:
J/MNRAS/507/5034
Date:
03 Dec 2021 13:07:03
Publisher:
CDS
Description:
In order to answer the open questions of modern cosmology and galaxy evolution theory, robust algorithms for calculating photometric redshifts (photo-z) for very large samples of galaxies are needed. Correct estimation of the various photo-z algorithms' performance requires attention to both the performance metrics and the data used for the estimation. In this work, we use the supervised machine learning algorithm MLPQNA (Multi-Layer Perceptron with Quasi-Newton Algorithm) to calculate photometric redshifts for the galaxies in the COSMOS2015 catalogue and the unsupervised Self-Organizing Maps (SOM) to determine the reliability of the resulting estimates. We find that for z_spec_<1.2, MLPQNA photo-z predictions are on the same level of quality as spectral energy distribution fitting photo-z. We show that the SOM successfully detects unreliable zspec that cause biases in the estimation of the photo-z algorithms' performance. Additionally, we use SOM to select the objects with reliable photo-z predictions. Our cleaning procedures allow us to extract the subset of objects for which the quality of the final photo-z catalogues is improved by a factor of 2, compared to the overall statistics.
3355. COSMOS2020 Farmer Catalog
ID:
ivo://irsa.ipac/COSMOS/Catalog/COSMOS2020F
Title:
COSMOS2020 Farmer Catalog
Short Name:
COSMOS2020F
Date:
06 Apr 2023 23:18:13
Publisher:
NASA/IPAC Infrared Science Archive
Description:
In these catalogues, source detection and multi-wavelength photometry is performed for 1.7 million sources in the 2 square degree COSMOS field. Approximately 966,000 of these sources are measured with all available broad-band data using both traditional aperture photometry and a new profile-fitting photometric tool, The Farmer, developed by the COSMOS team. Photometric redshifts are computed for all sources in each catalogue using two independent photometric redshift codes, LePhare and EAZY. At i < 21, sources have sub-percent photometric redshift precision and even the faintest sources at 25 < i < 27 reach a photometric redshift accuracy of 5%.
3356. COSMOS field Ly{alpha} emitters at z~5.7
ID:
ivo://CDS.VizieR/J/ApJS/172/523
Title:
COSMOS field Ly{alpha} emitters at z~5.7
Short Name:
J/ApJS/172/523
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a narrow-band optical survey of a contiguous area of 1.95deg^2^, covered by the Cosmic Evolution Survey (COSMOS). Both optical narrow-band ({lambda}c=8150{AA} and {delta}{lambda}=120{AA}) and broad-band (B, V, g', r', i', and z') imaging observations were performed with the Subaru prime-focus camera, Suprime-Cam on the Subaru Telescope. We provide the largest contiguous narrow-band survey, targeting Ly{alpha} emitters (LAEs) at z~5.7. We find a total of 119 LAE candidates at z~5.7. Over the wide-area covered by this survey, we find no strong evidence for large-scale clustering of LAEs. We estimate a star formation rate (SFR) density of ~7x10-4M_{sun}_/yr/Mpc^3^ for LAEs at z~5.7 and compare it with previous measurements.
3357. COSMOS field radio-loud AGN population at z>1
ID:
ivo://CDS.VizieR/J/A+A/567/A76
Title:
COSMOS field radio-loud AGN population at z>1
Short Name:
J/A+A/567/A76
Date:
21 Oct 2021
Publisher:
CDS
Description:
We select a sample of radio galaxies at high redshifts (z>1) in the COSMOS field by cross-matching optical and infrared (IR) images with the FIRST radio data. The aim of this study is to explore the high-z radio-loud (RL) active galactic nuclei (AGN) population at much lower luminosities than the classical samples of distant radio sources, which are similar to those of the local population of radio galaxies. Precisely, we extended a previous analysis focused on low-luminosity radio galaxies. The wide multiwavelength coverage provided by the COSMOS survey allows us to derive their spectral energy distributions (SEDs). We model them with our own developed technique 2SPD that includes old and young stellar populations and dust emission. When added to those previously selected, we obtain a sample of 74 RL AGN. The SED modeling returns several important quantities associated with the AGN and host properties. The resulting photometric redshifts range from z~0.7 to 3. The sample mostly includes compact radio sources but also 21 FR IIs sources; the radio power distribution of the sample covers ~10^31.5^-10^34.3^erg/s/Hz, thus straddling the local FR I/FR II break. The inferred range of stellar mass of the hosts is ~10^10^-10^11.5^M_{sun}_. The SEDs are dominated by the contribution from an old stellar population with an age of ~1-3Gyr for most of the sources. However, UV and mid-IR (MIR) excesses are observed for half of the sample. The dust luminosities inferred from the MIR excesses are in the range, L_dust_~10^43^-10^45.5^erg/s, which are associated with temperatures approximately of 350-1200K. Estimates of the UV component yield values of ~10^41.5^-10^45.5^erg/s at 2000{AA}. The UV emission is significantly correlated with both IR and radio luminosities; the former being the stronger link. However, the origin of UV and dust emission, whether it is produced by the AGN of by star formation, is still unclear. Our results show that this RLAGN population at high redshifts displays a wide variety of properties. Low-power radio galaxies, which are associated with UV- and IR-faint hosts are generally similar to red massive galaxies of the local FR Is. At the opposite side of the radio luminosity distribution, large MIR and UV excesses are observed in objects consistent with quasar-like AGN, as also proved by their high dust temperatures, which are more similar to local FR IIs.
3358. COSMOS field supermassive black holes
ID:
ivo://CDS.VizieR/J/MNRAS/427/3103
Title:
COSMOS field supermassive black holes
Short Name:
J/MNRAS/427/3103
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using the wide multiband photometry available in the Cosmic Evolution Survey (COSMOS) field, we explore the host galaxy properties of a large sample of active galactic nuclei (AGNs; ~1700 objects) with L_bol_ranging from 10^43^ to 10^47^erg/s, obtained by combining X-ray and optical spectroscopic selections. Based on a careful study of their spectral energy distributions, which have been parametrized using a two-component (AGN+galaxy) model fit, we have derived dust-corrected rest-frame magnitudes, colours and stellar masses of the obscured and unobscured AGN hosts up to high redshift (z<~3). Moreover, for the sample of obscured AGNs, we have also derived reliable star formation rates (SFRs). We find that AGN hosts span a large range of stellar masses and SFRs. No colour-bimodality is seen at any redshift in the AGN hosts, which are found to be mainly massive, red galaxies. Once we have accounted for the colour-mass degeneracy in well-defined mass-matched samples, we find a residual (marginal) enhancement of the incidence of AGNs in redder galaxies with lower specific SFRs. We argue that this result might emerge because of our ability to properly account for AGN light contamination and dust extinction, compared to surveys with a more limited multiwavelength coverage. However, because these colour shifts are relatively small, systematic effects could still be considered responsible for some of the observed trends. Interestingly, we find that the probability for a galaxy to host a black hole that is growing at any given `specific accretion rate' (i.e. the ratio of X-ray luminosity to the host stellar mass) is almost independent of the host galaxy mass, while it decreases as a power law with L_X_/M_*_. By analysing the normalization of such a probability distribution, we show how the incidence of AGNs increases with redshift as rapidly as (1 + {\em z})^4^, which closely resembles the overall evolution of the specific SFR of the entire galaxy population. We provide analytical fitting formulae that describe the probability of a galaxy of any mass (above the completeness limit of the COSMOS) to host an AGN of any given specific accretion rate as a function of redshift. These can be useful tools for theoretical studies of the growing population of black holes within galaxy evolution models. Although AGN activity and star formation in galaxies do appear to have a common triggering mechanism, at least in a statistical sense, within the COSMOS sample, we do not find any conclusive evidence to suggest that AGNs have a powerful influence on the star-forming properties of their host galaxies.
3359. COSMOS field variability-selected AGN nuclei
ID:
ivo://CDS.VizieR/J/A+A/574/A112
Title:
COSMOS field variability-selected AGN nuclei
Short Name:
J/A+A/574/A112
Date:
21 Oct 2021
Publisher:
CDS
Description:
Active galaxies are characterized by variability at every wavelength, with timescales from hours to years depending on the observing window. Optical variability has proven to be an effective way of detecting AGNs in imaging surveys, lasting from weeks to years. In the present work we test the use of optical variability as a tool to identify active galactic nuclei in the VST multiepoch survey of the COSMOS field, originally tailored to detect supernova events. We make use of the multiwavelength data provided by other COSMOS surveys to discuss the reliability of the method and the nature of our AGN candidates. The selection on the basis of optical variability returns a sample of 83 AGN candidates; based on a number of diagnostics, we conclude that 67 of them are confirmed AGNs (81% purity), 12 are classified as supernovae, while the nature of the remaining 4 is unknown. For the subsample of AGNs with some spectroscopic classification, we find that Type 1 are prevalent (89%) compared to Type 2 AGNs (11%). Overall, our approach is able to retrieve on average 15% of all AGNs in the field identified by means of spectroscopic or X-ray classification, with a strong dependence on the source apparent magnitude (completeness ranging from 26% to 5%). In particular, the completeness for Type 1 AGNs is 25%, while it drops to 6% for Type 2 AGNs. The rest of the X-ray selected AGN population presents on average a larger rms variability than the bulk of non-variable sources, indicating that variability detection for at least some of these objects is prevented only by the photometric accuracy of the data. The low completeness is in part due to the short observing span: we show that increasing the temporal baseline results in larger samples as expected for sources with a red-noise power spectrum. Our results allow us to assess the usefulness of this AGN selection technique in view of future wide-field surveys.
3360. COSMOS Field VLBA Observations 1.4-GHz Source Catalog
ID:
ivo://nasa.heasarc/cosmosvlba
Title:
COSMOS Field VLBA Observations 1.4-GHz Source Catalog
Short Name:
COSMOSVLBA
Date:
07 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the results of a project using wide-field Very Long Baseline Interferometry (VLBI) observations at 1.4 GHz of 2,865 known radio sources in the Cosmic Evolution Survey (COSMOS) field, a field which has exceptional multi-wavelength coverage. The main objective of this study is to identify the active galactic nuclei (AGN) in this field. Wide-field VLBI observations were made of all known radio sources in the COSMOS field at 1.4 GHz using the Very Long Baseline Array (VLBA). The authors also collected complementary multiwavelength information from the literature for the VLBA-detected sources.The combination of the number of sources, sensitivity, angular resolution and the area covered by this project are unprecedented. A catalog which contains the VLBI-detected sources is presented, the main purpose of which is to be used as an AGN catalog. the complementary multiwavelength (optical, infrared and X-ray) information of the VLBI-detected sources is also presented. The authors have detected 468 radio sources, expected to be AGN, with the VLBA. This is, to date, the largest sample assembled of VLBI-detected sources in the sub-mJy regime. They find a detection fraction of 20% +/- 1%, considering only those sources from the input catalog which were in principle detectable with the VLBA (2,361). As a function of the VLA flux density, the detection fraction is higher for higher flux densities, since at high flux densities a source could be detected even if the VLBI core accounts for a small percentage of the total flux density. As a function of redshift, the authors see no evolution of the detection fraction over the redshift range 0.5 &lt; z &lt; 3. In addition, they find that faint radio sources typically have a greater fraction of their radio luminosity in a compact core: ~70% of the sub-mJy sources detected with the VLBA have more than half of their total radio luminosity in a VLBI-scale component, whereas this is true for only ~30% of the sources that are brighter than 10 mJy. This suggests that fainter radio sources differ intrinsically from brighter ones. Across the entire sample, the authors find the predominant morphological classification of the host galaxies of the VLBA-detected sources to be early type (57%), although this varies with redshift and at z &gt; 1.5 they find that spiral galaxies become the most prevalent (48%). The number of detections is high enough to study the faint radio population with statistically significant numbers. The authors demonstrate that wide-field VLBI observations, together with new calibration methods such as multi-source self-calibration and mosaicking, result in information which is difficult or impossible to obtain otherwise. This table contains 504 entries, including the 468 VLBA-detected sources and, for sources with multiple components, entries for the individual components. Among the detected sources, there are 452 single, 13 double, 2 triple and 1 quadruple source. Source entries have no suffix in their vlba_source_id, e.g., &#39;C3293&#39;, whereas component entries have a, b, c or d suffixes, e.g., &#39;C0090a&#39; (and a value of 2 for the multi_cpt_flag parameter). This table was created by the HEASARC in December 2017 based on &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/607/A132"&gt;CDS Catalog J/A+A/607/A132&lt;/a&gt; files vlba_cat.dat and vlba_mw.dat. This is a service provided by NASA HEASARC .

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