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2411. 10C cont.: a deeper radio survey at 15.7GHz
ID:
ivo://CDS.VizieR/J/MNRAS/457/1496
Title:
10C cont.: a deeper radio survey at 15.7GHz
Short Name:
J/MNRAS/457/1496
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present deep 15.7-GHz observations made with the Arcminute Microkelvin Imager (AMI) Large Array in two fields previously observed as part of the Tenth Cambridge (10C) survey. These observations allow the source counts to be calculated down to 0.1mJy, a factor of five deeper than achieved by the 10C survey. The new source counts are consistent with the extrapolated fit to the 10C source count, and display no evidence for either steepening or flattening of the counts. There is thus no evidence for the emergence of a significant new population of sources (e.g. starforming) at 15.7GHz flux densities above 0.1mJy, the flux density level at which we expect starforming galaxies to begin to contribute. Comparisons with the de Zotti et al. model and the SKADS Simulated Sky show that they both underestimate the observed number of sources by a factor of two at this flux density level. We suggest that this is due to the flat-spectrum cores of radio galaxies contributing more significantly to the counts than predicted by the models.
2412. 9C Continued 15-GHz Ryle Telescope Survey of VSA Fields Source Catalog
ID:
ivo://nasa.heasarc/rt9cc15ghz
Title:
9C Continued 15-GHz Ryle Telescope Survey of VSA Fields Source Catalog
Short Name:
RT9CC15GHZ
Date:
28 Feb 2025
Publisher:
NASA/GSFC HEASARC
Description:
The 9C (9th Cambridge) survey of radio sources with the Ryle Telescope at 15.2 GHz was set up to survey the fields of the cosmic microwave background telescope, the Very Small Array (VSA). In their first paper (Waldram et al. 2003, MNRAS, 342, 915), the authors described three regions of the survey, constituting a total area of 529 deg<sup>2</sup> to a completeness limit of ~ 25 mJy. In this follow-up, they present results from a series of deeper regions, constituting a total area of 115 deg<sup>2</sup> complete to ~ 10 mJy and of 29 deg<sup>2</sup> complete to ~ 5.5 mJy. The authors have investigated the source counts and the distributions of the 1.4 to 15.2 GHz spectral indices for these deeper samples. The whole catalog of 643 sources is contained in the present table. Down to their lower limit of 5.5 mJy, the authors detect no evidence for any change in the differential source count from the earlier fitted count above 25 mJy, n(S) = 51(S/Jy)<sup>-2.15</sup> Jy<sup>-1</sup> sr<sup>-1</sup>. They matched both their new and earlier catalogues with the NRAO VLA Sky Survey (NVSS) catalogue at 1.4 GHz and selected flux-limited samples at both 15 and 1.4 GHz. As they expected, they found that the proportions of sources with flat and rising spectra in the samples selected at 15 GHz are significantly higher than those in the samples selected at 1.4 GHz. In addition, for 15-GHz samples selected in three flux density ranges, they detect a significant shift in the median value of the 1.4 to 15.2 GHz spectral index: the higher the flux densities, the higher the proportions of sources with flat and rising spectra. In the area complete to ~ 10 mJy, the authors find five sources between 10 and 15 mJy at 15 GHz, amounting to 4.3 per cent of sources in this range, with no counterpart in the NVSS catalogue. This implies that, had they relied on the NVSS for locating their sources, they could have missed a significant proportion of them at low flux densities. These results illustrate the problems inherent in using a low-frequency catalog to characterize the source population at a much higher frequency and emphasize the value of a blind 15.2-GHz survey. This table was created in November 2010 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/404/1005">CDS catalog J/MNRAS/404/1005</a> file 9c_cont.dat. This is a service provided by NASA HEASARC .
2413. C-COSMOS & ChaMP X-ray-selected z>3 AGNs
ID:
ivo://CDS.VizieR/J/MNRAS/445/1430
Title:
C-COSMOS & ChaMP X-ray-selected z>3 AGNs
Short Name:
J/MNRAS/445/1430
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from an analysis of the largest high-redshift (z>3) X-ray-selected active galactic nucleus (AGN) sample to date, combining the Chandra Cosmological Evolution Survey and Chandra Multi-wavelength Project surveys and doubling the previous samples. The sample comprises 209 X-ray-detected AGNs, over a wide range of rest-frame 2-10keV luminosities logLX=43.3-46.0erg/s. X-ray hardness rates show that ~39 per cent of the sources are highly obscured, N_H_>10^22^cm^-2^, in agreement with the ~37 per cent of type-2 AGNs found in our sample based on their optical classification. For ~26 per cent of objects have mismatched optical and X-ray classifications. Utilizing the 1/Vmax method, we confirm that the comoving space density of all luminosity ranges of AGNs decreases with redshift above z>3 and up to z~7. With a significant sample of AGNs (N=27) at z>4, it is found that both source number counts in the 0.5-2keV band and comoving space density are consistent with the expectation of a luminosity-dependent density evolution (LDDE) model at all redshifts, while they exclude the luminosity and density evolution (LADE) model. The measured comoving space density of type-1 and type-2 AGNs shows a constant ratio between the two types at z>3. Our results for both AGN types at these redshifts are consistent with the expectations of LDDE model.
2414. C-COSMOS Legacy sources multiwavelength catalog
ID:
ivo://CDS.VizieR/J/ApJ/817/34
Title:
C-COSMOS Legacy sources multiwavelength catalog
Short Name:
J/ApJ/817/34
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the catalog of optical and infrared counterparts of the Chandra COSMOS-Legacy Survey, a 4.6Ms Chandra program on the 2.2deg^2^ of the COSMOS field, combination of 56 new overlapping observations obtained in Cycle 14 with the previous C-COSMOS survey. In this Paper we report the i, K, and 3.6{mu}m identifications of the 2273 X-ray point sources detected in the new Cycle 14 observations. We use the likelihood ratio technique to derive the association of optical/infrared (IR) counterparts for 97% of the X-ray sources. We also update the information for the 1743 sources detected in C-COSMOS, using new K and 3.6{mu}m information not available when the C-COSMOS analysis was performed. The final catalog contains 4016 X-ray sources, 97% of which have an optical/IR counterpart and a photometric redshift, while ~54% of the sources have a spectroscopic redshift. The full catalog, including spectroscopic and photometric redshifts and optical and X-ray properties described here in detail, is available online. We study several X-ray to optical (X/O) properties: with our large statistics we put better constraints on the X/O flux ratio locus, finding a shift toward faint optical magnitudes in both soft and hard X-ray band. We confirm the existence of a correlation between X/O and the the 2-10keV luminosity for Type 2 sources. We extend to low luminosities the analysis of the correlation between the fraction of obscured AGNs and the hard band luminosity, finding a different behavior between the optically and X-ray classified obscured fraction.
2415. CCPC. II. 2<z<6.6 protocluster candidates
ID:
ivo://CDS.VizieR/J/ApJ/833/15
Title:
CCPC. II. 2<z<6.6 protocluster candidates
Short Name:
J/ApJ/833/15
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Candidate Cluster and Protocluster Catalog (CCPC) is a list of objects at redshifts z>2 composed of galaxies with spectroscopically confirmed redshifts that are coincident on the sky and in redshift. These protoclusters are identified by searching for groups in volumes corresponding to the expected size of the most massive protoclusters at these redshifts. In CCPC1 we identified 43 candidate protoclusters among 14000 galaxies between 2.74<z<3.71. Here we expand our search to more than 40000 galaxies with spectroscopic redshifts z>2.00, resulting in an additional 173 candidate structures. The most significant of these are 36 protoclusters with overdensities {delta}_gal_>7. We also identify three large proto-supercluster candidates containing multiple protoclusters at z=2.3, 3.5 and z=6.56. Eight candidates with N>=10 galaxies are found at redshifts z>4.0. The last system in the catalog is the most distant spectroscopic protocluster candidate known to date at z=6.56.
2416. ^12^C/^13^C ratio for 18 galactic R CrB stars
ID:
ivo://CDS.VizieR/J/ApJ/747/102
Title:
^12^C/^13^C ratio for 18 galactic R CrB stars
Short Name:
J/ApJ/747/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
Observed spectra of R Coronae Borealis (RCB) and hydrogen-deficient carbon (HdC) stars are analyzed by synthesizing the C_2_ Swan bands (1, 0), (0, 0), and (0, 1) using our detailed line list and the Uppsala model atmospheres. The (0, 1) and (0, 0) C_2_ bands are used to derive the ^12^C abundance, and the (1, 0) ^12^C^13^C band to determine the ^12^C/^13^C ratios. The carbon abundance derived from the C_2_ Swan bands is about the same for the adopted models constructed with different carbon abundances over the range 8.5 (C/He=0.1%) to 10.5 (C/He=10%). Carbon abundances derived from C I lines are about a factor of four lower than the carbon abundance of the adopted model atmosphere over the same C/He interval, as reported by Asplund et al., who dubbed the mismatch between adopted and derived C abundance as the "carbon problem." In principle, the carbon abundances obtained from C_2_ Swan bands and that assumed for the model atmosphere can be equated for a particular choice of C/He that varies from star to star. Then, the carbon problem for C_2_ bands is eliminated. However, such C/He ratios are in general less than those of the extreme helium stars, the seemingly natural relatives to the RCB and HdC stars. A more likely solution to the C_2_ carbon problem may lie in a modification of the model atmosphere's temperature structure. The derived carbon abundances and the ^12^C/^13^C ratios are discussed in light of the double degenerate and the final flash scenarios.
2417. C2D Candidate YSO CLOUDS Catalog
ID:
ivo://irsa.ipac/Spitzer/Catalog/C2D/C2D-YSOCLOUDS
Title:
C2D Candidate YSO CLOUDS Catalog
Short Name:
C2D-YSOCLOUDS
Date:
01 Oct 2018 20:27:17
Publisher:
NASA/IPAC Infrared Science Archive
Description:
The Cores to Disks (C2D) Spitzer Legacy Program used all three Spitzer instruments (IRAC, MIPS, and IRS) to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star-forming environments. In addition to targeting about 150 known compact cores, it surveyed with IRAC and MIPS (3.6-70 mum) the entire areas of five of the nearest large molecular clouds for new candidate protostars and substellar objects as faint as 0.001 solar luminosities. C2D observed with IRAC and MIPS about 190 systems likely to be in the early stages of planetary system formation (ages up to about 10 Myr), probing the evolution of the circumstellar dust, the raw material for planetary cores. The Candidate YSO CLOUDS Catalog lists the candidate young stellar objects (YSOs) in the C2D CLOUDS fields (ChamaeleonII (CHA_II), Lupus (LUP), Ophiuchus (OPH), Perseus (PER) and Serpens (SER)). It is derived from the Full Catalog using methodology described in Harvey et al. (2007b).
2418. C2D Candidate YSO CORES Catalog
ID:
ivo://irsa.ipac/Spitzer/Catalog/C2D/C2D-YSOCORES
Title:
C2D Candidate YSO CORES Catalog
Short Name:
C2D-YSOCORES
Date:
01 Oct 2018 20:27:17
Publisher:
NASA/IPAC Infrared Science Archive
Description:
The Cores to Disks (C2D) Spitzer Legacy Program used all three Spitzer instruments (IRAC, MIPS, and IRS) to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star-forming environments. In addition to targeting about 150 known compact cores, it surveyed with IRAC and MIPS (3.6-70 mum) the entire areas of five of the nearest large molecular clouds for new candidate protostars and substellar objects as faint as 0.001 solar luminosities. C2D observed with IRAC and MIPS about 190 systems likely to be in the early stages of planetary system formation (ages up to about 10 Myr), probing the evolution of the circumstellar dust, the raw material for planetary cores. The Candidate YSO CORES Catalog lists the candidate young stellar objects (YSOs) in the C2D CORES fields (82 small cloud cores). It is derived from the Full Catalog using methodology described in Harvey et al. (2007b).
2419. C2D Candidate YSO OFF-CLOUD Catalog
ID:
ivo://irsa.ipac/Spitzer/Catalog/C2D/C2D-YSOOFFCLOUDS
Title:
C2D Candidate YSO OFF-CLOUD Catalog
Short Name:
C2D-YSOOFFCLOUDS
Date:
01 Oct 2018 20:27:17
Publisher:
NASA/IPAC Infrared Science Archive
Description:
The Cores to Disks (C2D) Spitzer Legacy Program used all three Spitzer instruments (IRAC, MIPS, and IRS) to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star-forming environments. In addition to targeting about 150 known compact cores, it surveyed with IRAC and MIPS (3.6-70 mum) the entire areas of five of the nearest large molecular clouds for new candidate protostars and substellar objects as faint as 0.001 solar luminosities. C2D observed with IRAC and MIPS about 190 systems likely to be in the early stages of planetary system formation (ages up to about 10 Myr), probing the evolution of the circumstellar dust, the raw material for planetary cores. The Candidate YSO OFF-CLOUD Catalog lists the candidate young stellar objects (YSOs) in the C2D OFF-CLOUD fields (ChamaeleonII (CHA_II), Lupus (LUP), Ophiuchus (OPH), Perseus (PER) and Serpens (SER)). It is derived from the Full Catalog using methodology described in Harvey et al. (2007b).
2420. C2D Candidate YSO STARS Catalog
ID:
ivo://irsa.ipac/Spitzer/Catalog/C2D/C2D-YSOSTARS
Title:
C2D Candidate YSO STARS Catalog
Short Name:
C2D-YSOSTARS
Date:
01 Oct 2018 20:27:17
Publisher:
NASA/IPAC Infrared Science Archive
Description:
The Cores to Disks (C2D) Spitzer Legacy Program used all three Spitzer instruments (IRAC, MIPS, and IRS) to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star-forming environments. In addition to targeting about 150 known compact cores, it surveyed with IRAC and MIPS (3.6-70 mum) the entire areas of five of the nearest large molecular clouds for new candidate protostars and substellar objects as faint as 0.001 solar luminosities. C2D observed with IRAC and MIPS about 190 systems likely to be in the early stages of planetary system formation (ages up to about 10 Myr), probing the evolution of the circumstellar dust, the raw material for planetary cores. The Candidate YSO STARS Catalog lists the candidate young stellar objects (YSOs) in the C2D STARS fields (160 targeted stars). It is derived from the Full Catalog using methodology described in Harvey et al. (2007b).

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