- ID:
- ivo://CDS.VizieR/J/ApJ/757/83
- Title:
- The Blanco Cosmology Survey (BCS)
- Short Name:
- J/ApJ/757/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Blanco Cosmology Survey (BCS) is a 60 night imaging survey of ~80deg^2^ of the southern sky located in two fields: (5hr,-55{deg}) and (23hr,-55{deg}). The survey was carried out between 2005 and 2008 in griz bands with the Mosaic2 imager on the Blanco 4m telescope. The primary aim of the BCS survey is to provide the data required to optically confirm and measure photometric redshifts for Sunyaev-Zel'dovich effect selected galaxy clusters from the South Pole Telescope and the Atacama Cosmology Telescope. We process and calibrate the BCS data, carrying out point-spread function-corrected model-fitting photometry for all detected objects. The median 10{sigma} galaxy (point-source) depths over the survey in griz are approximately 23.3 (23.9), 23.4 (24.0), 23.0 (23.6), and 21.3 (22.1), respectively. The astrometric accuracy relative to the USNO-B survey is ~45mas. We calibrate our absolute photometry using the stellar locus in grizJ bands, and thus our absolute photometric scale derives from the Two Micron All Sky Survey, which has ~2% accuracy. The scatter of stars about the stellar locus indicates a systematic floor in the relative stellar photometric scatter in griz that is ~1.9%, ~2.2%, ~2.7%, and ~2.7%, respectively. A simple cut in the AstrOmatic star-galaxy classifier spread_ model produces a star sample with good spatial uniformity. We use the resulting photometric catalogs to calibrate photometric redshifts for the survey and demonstrate scatter {delta}z/(1+z)=0.054 with an outlier fraction {eta}<5% to z~1. We highlight some selected science results to date and provide a full description of the released data products.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/157/148
- Title:
- The blueshift of the C IV broad emission line in QSOs
- Short Name:
- J/AJ/157/148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the sample from Ge et al. (2016MNRAS.462..966G) of 87 low-z Palomar-Green quasi-stellar objects (QSOs) and 130 high-z QSOs (0<z<5) with H{beta}-based single-epoch supermassive black hole masses, we perform a uniform decomposition of the C IV {lambda}1549 broad-line profile. Based on the rest frame defined by the [O III] {lambda}5007 narrow emission line, a medium-strong positive correlation is found between the C IV blueshift and the luminosity at 5100 {AA} or the Eddington ratio L_Bol_/L_Edd_. A medium-strong negative relationship is found between the C IV blueshift and C IV equivalent width. These results support the postulation where the radiation pressure may be the driver of C IV blueshift. There is a medium-strong correlation between the mass ratio of C IV-based to H{beta}-based M_BH_ and the C IV blueshift, which indicates that the bias for C IV-based M_BH_ is affected by the C IV profile.
- ID:
- ivo://CDS.VizieR/J/ApJ/824/86
- Title:
- The BOSS emission-line lens survey. III.
- Short Name:
- J/ApJ/824/86
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey GALaxy-Ly{alpha} EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Ly{alpha} emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy-LAE candidates selected from ~1.4x10^6^ galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2-3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.
- ID:
- ivo://CDS.VizieR/J/ApJS/243/24
- Title:
- The CASBaH galaxy redshift survey
- Short Name:
- J/ApJS/243/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the survey for galaxies in the fields surrounding nine sightlines to far-UV bright, z~1 quasars that define the COS Absorption Survey of Baryon Harbors (CASBaH) program. The photometry and spectroscopy that comprise the data set come from a mixture of public surveys (SDSS, DECaLS) and our dedicated efforts on private facilities (Keck, MMT, LBT). We report the redshifts and stellar masses for 5902 galaxies within ~10 comoving-Mpc of the sightlines with a median of \bar{z}=0.28 and \bar{M}_*_~10^10.1^M_{sun}_. This data set, publicly available as the CASBaH specDB, forms the basis of several recent and ongoing CASBaH analyses. Here, we perform a clustering analysis of the galaxy sample with itself (auto-correlation) and against the set of O VI absorption systems (cross-correlation) discovered in the CASBaH quasar spectra with column densities N(O^+5^)>=10^13.5^/cm^2^. For each, we describe the measured clustering signal with a power-law correlation function {xi}(r)=(r/r_0_)^-{gamma}^ and find that (r_0_,{gamma})=(5.48+/-0.07h_100_^-1^Mpc,1.33+/-0.04) for the auto-correlation and (6.00_-0.77_^+1.09^h_100_^-1^Mpc,1.25+/-0.18) for galaxy-OVI cross-correlation. We further estimate a bias factor of b_gg_=1.3+/-0.1 from the galaxy-galaxy auto-correlation, indicating the galaxies are hosted by halos with mass M_halo_~10^12.1+/-0.05^M_{sun}_. Finally, we estimate an OVI-galaxy bias factor b_OVI_=1.0+/-0.1 from the cross-correlation which is consistent with OVI absorbers being hosted by dark matter halos with typical mass M_halo_~10^11^M_{sun}_. Future works with upcoming data sets (e.g., CGM2) will improve upon these results and will assess whether any of the detected OVI arises in the intergalactic medium.
- ID:
- ivo://CDS.VizieR/J/ApJS/195/10
- Title:
- The CDF-S survey: 4Ms source catalogs
- Short Name:
- J/ApJS/195/10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present source catalogs for the 4Ms Chandra Deep Field-South (CDF-S), which is the deepest Chandra survey to date and covers an area of 464.5arcmin^2^. We provide a main Chandra source catalog, which contains 740 X-ray sources that are detected with wavdetect at a false-positive probability threshold of 10^-5^ in at least one of three X-ray bands (0.5-8keV, full band; 0.5-2keV, soft band; and 2-8keV, hard band) and also satisfy a binomial-probability source-selection criterion of P<0.004 (i.e., the probability of sources not being real is less than 0.004); this approach is designed to maximize the number of reliable sources detected. A total of 300 main-catalog sources are new compared to the previous 2Ms CDF-S main-catalog sources. We determine X-ray source positions using centroid and matched-filter techniques and obtain a median positional uncertainty of ~0.42". We also provide a supplementary catalog, which consists of 36 sources that are detected with wavdetect at a false-positive probability threshold of 10^-5^, satisfy the condition of 0.004<P<0.1, and have an optical counterpart with R<24. Multiwavelength identifications, basic optical/infrared/radio photometry, and spectroscopic/photometric redshifts are provided for the X-ray sources in the main and supplementary catalogs. Seven hundred sixteen (~97%) of the 740 main-catalog sources have multiwavelength counterparts, with 673 (~94% of 716) having either spectroscopic or photometric redshifts. Basic analyses of the X-ray and multiwavelength properties of the sources indicate that >75% of the main-catalog sources are active galactic nuclei (AGNs); of the 300 new main-catalog sources, about 35% are likely normal and starburst galaxies, reflecting the rise of normal and starburst galaxies at the very faint flux levels uniquely accessible to the 4Ms CDF-S.
1356. The CfA2S catalog
- ID:
- ivo://CDS.VizieR/J/ApJS/121/287
- Title:
- The CfA2S catalog
- Short Name:
- J/ApJS/121/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present redshifts for a sample of 4391 galaxies with magnitude m_B(0)_<=15.5 covering 20h<=RA<=4h in right ascension and -2.5{deg}<=DE<=90{deg} in declination. This sample is complete for all galaxies in the merge of the Zwicky et al. and Nilson catalogs in the south Galactic cap. Redshifts for 2964 of these were measured as part of the second CfA Redshift Survey. The data reveal large voids in the foreground and background of the Perseus-Pisces Supercluster. The largest of these voids lies at a mean velocity ~8000km/s, has diameter ~5000km/s, and is enclosed by a complex of dense structures. The large structure known as the Perseus-Pisces Supercluster forms the near side of this complex. On the far side of this large void, at a mean velocity ~12000km/s, there is another coherent dense wall. The structures in this survey support the view that galaxies generally lie on surfaces surrounding or nearly surrounding low-density regions or voids.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/66
- Title:
- The CGM-GRB study. I. GRB hosts at z~2-6
- Short Name:
- J/ApJ/884/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies have revealed a dynamic interplay between the galaxy ecosystem and circumgalactic medium (CGM). We investigate the CGM at high redshifts (z>~2) by using bright afterglows of gamma-ray bursts (GRBs) as background sources. We compiled a sample of medium-resolution ({Delta}v<50km/s) and high signal-to-noise ratio (typical S/N~10) spectra from 27 GRB afterglows covering z~2-6, with six of them at z>~4. We analyzed the high- and low-ionization absorption features within +/-400km/s to extract the CGM and interstellar medium (ISM) kinematics. In the stacked spectra, high-ionization absorption profiles (e.g., CIV, SiIV) present significant absorption excess in their blue wings (v{<}-100km/s) relative to the red wings (v>100km/s). The stronger blue wings in high-ionization species are indicative of the presence of ubiquitous warm outflows in the GRB hosts at high redshifts. We used simple toy models to kinematically distinguish the CGM and ISM absorption and estimate the CGM mass and outflow velocity. We find tentative evidence of the evolution of the CGM metal mass by ~0.5dex between two redshift bins, each spanning 1 Gyr, z1: 2-2.7 and z2: 2.7-5. By comparing with past studies, we find that over the course of evolution of present-day galaxies with M_*_>10^10^M_{sun}_, the ratio of CIV mass in the CGM to the stellar mass remains fairly uniform, with log(M_CIV_/M_*_)~-4.5 within +/-0.5dex from z~4 to z~0, suggesting CGM-galaxy coevolution.
- ID:
- ivo://CDS.VizieR/J/ApJS/236/48
- Title:
- The Chandra UDS survey (X-UDS)
- Short Name:
- J/ApJS/236/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the X-UDS survey, a set of wide and deep Chandra observations of the Subaru-XMM Deep/UKIDSS Ultra Deep Survey (SXDS/UDS) field. The survey consists of 25 observations that cover a total area of 0.33deg^2^. The observations are combined to provide a nominal depth of ~600ks in the central 100arcmin^2^ region of the field that has been imaged with Hubble/WFC3 by the CANDELS survey and ~200ks in the remainder of the field. In this paper, we outline the survey's scientific goals, describe our observing strategy, and detail our data reduction and point source detection algorithms. Our analysis has resulted in a total of 868 band-merged point sources detected with a false-positive Poisson probability of <1x10^-4^. In addition, we present the results of an X-ray spectral analysis and provide best-fitting neutral hydrogen column densities, N_H_, as well as a sample of 51 Compton-thick active galactic nucleus candidates. Using this sample, we find the intrinsic Compton-thick fraction to be 30%-35% over a wide range in redshift (z=0.1-3), suggesting the obscured fraction does not evolve very strongly with epoch. However, if we assume that the Compton-thick fraction is dependent on luminosity, as is seen for Compton-thin sources, then our results are consistent with a rise in the obscured fraction out to z~3. Finally, an examination of the host morphologies of our Compton-thick candidates shows a high fraction of morphological disturbances, in agreement with our previous results.
1359. The CNOC2 survey. I.
- ID:
- ivo://CDS.VizieR/J/ApJS/129/475
- Title:
- The CNOC2 survey. I.
- Short Name:
- J/ApJS/129/475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Canadian Network for Observational Cosmology Field Galaxy Redshift Survey (CNOC2) obtained spectroscopic redshifts for about 6200 galaxies to a nominal limit of R=21.5. The survey area of about 1.5 square degrees was spread over four patches on the sky. This catalog presents photometry and redshifts for all galaxies in the CNOC2 0223+00 Patch (area of 1409 square arcminutes). A future paper will provide catalogs for the other three patches.
- ID:
- ivo://CDS.VizieR/J/ApJ/872/81
- Title:
- The COS CGM Compendium (CCC). II. Lyman limit syst.
- Short Name:
- J/ApJ/872/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from our COS circumgalactic medium (CGM) compendium (CCC), a survey of the CGM at z<~1 using HI-selected absorbers with 15<logN_HI_<19. We focus here on 82 partial Lyman limit systems (pLLSs, 16.2<=logN_HI_<17.2) and 29 LLSs (17.2<=logN_HI_<19). Using Bayesian techniques and Markov Chain Monte Carlo sampling of a grid of photoionization models, we derive the posterior probability distribution functions (PDFs) for the metallicity of each absorber in CCC. We show that the combined pLLS metallicity PDF at z<~1 has two main peaks at [X/H]~-1.7 and -0.4, with a strong dip at [X/H]~-1. The metallicity PDF of the LLSs might be more complicated than a unimodal or bimodal distribution. The pLLSs and LLSs probe a similar range of metallicities -3<~[X/H]<~+0.4, but the fraction of very metal-poor absorbers with [X/H]<~-1.4 is much larger for the pLLSs than the LLSs. In contrast, absorbers with logN_HI_>=19 have mostly -1<~[X/H]<~0 at z<~1. The metal-enriched gas probed by pLLSs and LLSs confirms that galaxies that have been enriching their CGM over billions of years. Surprisingly, despite this enrichment, there is also abundant metal-poor CGM gas (41%-59% of the pLLSs have [X/H]<~-1.4), representing a reservoir of near-pristine gas around z<~1 galaxies. We compare our empirical results to recent cosmological zoom simulations, finding some discrepancies, including an overabundance of metal- enriched CGM gas in simulations.