- ID:
- ivo://CDS.VizieR/J/ApJS/116/211
- Title:
- CNOC cluster redshift survey catalogs. IV.
- Short Name:
- J/ApJS/116/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and redshift catalogs of galaxies in the field of two rich galaxy clusters, MS 1358.4+6245 (z=0.328) and MS 1008.1-1224 (z=0.306), are presented as part of the Canadian Network for Observation Cosmology (CNOC) cluster redshift survey carried out at the Canada-France-Hawaii Telescope (CFHT) using the MOS imaging multiobject spectrograph. The imaging and spectroscopic observations cover a mosaic of three MOS fields in the north-south direction of a total area of approximately 23.3'x9.0' for MS 1358.4+6245 and a single field of 7.9'x9.0' for MS 1008.1-1224. Redshifts for 361 galaxies, primarily ranging in magnitude from r=20 to r=22, and Gunn r and g photometry for 3015 galaxies to r=24mag were obtained. The data set is also presented graphically in several forms. The magnitude, color, and geometric selection functions for the redshift sample are presented and discussed.
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- ID:
- ivo://CDS.VizieR/J/ApJS/116/231
- Title:
- CNOC cluster redshift survey catalogs. V.
- Short Name:
- J/ApJS/116/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometric and redshift catalogs of galaxies in the field of two rich galaxy clusters: MS 1224.7+2007 (z=0.327) and MS 1512.4+3647 (z=0.372) are presented as part of the Canadian Network for Observation Cosmology (CNOC) cluster redshift survey carried out at the Canada-France-Hawaii Telescope (CFHT) using the MOS imaging multiobject spectrograph. The imaging and spectroscopic observations span three contiguous MOS fields in the east-west direction for MS 1512.4+3647, covering a total area of approximately 8.0'x27.3'. A single field of 7.1'x9.0' was obtained for MS 1224.7+2007. Redshifts for 287 galaxies in the MS 1512.4+3647 fields and 75 galaxies in the MS 1224.7+2007 field (primarily ranging in magnitude from r=18-22) were obtained. The spectroscopic information in this paper is supplemented by photometric information for all galaxies in the fields down to Gunn r=21mag. The data set is also presented graphically in several forms. The magnitude, color, and geometric selection functions for the redshift sample are presented and discussed.
- ID:
- ivo://CDS.VizieR/J/ApJS/116/247
- Title:
- CNOC cluster redshift survey catalogs. VI.
- Short Name:
- J/ApJS/116/247
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A photometric and redshift catalog of galaxies in the field of two rich galaxy clusters, MS 0015.9+1609 (z=0.5481) and MS 0451.5-0305 (z=0.5386), is presented as part of the Canadian Network for Observation Cosmology (CNOC) cluster redshift survey carried out at the Canada-France-Hawaii Telescope (CFHT) using the MOS imaging multiobject spectrograph. The imaging and spectroscopic observations cover a single field of approximately 7.6'x9.1', centered on each cluster. Redshifts for 247 galaxies, primarily ranging in magnitude from r=20 to r=22, were obtained. The data set is also presented graphically in several forms. The magnitude, color, and geometric selection functions for the redshift sample are presented and discussed.
254. CNSS pilot survey
- ID:
- ivo://CDS.VizieR/J/ApJ/818/105
- Title:
- CNSS pilot survey
- Short Name:
- J/ApJ/818/105
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have commenced a multiyear program, the Caltech-NRAO Stripe 82 Survey (CNSS), to search for radio transients with the Jansky VLA in the Sloan Digital Sky Survey Stripe 82 region. The CNSS will deliver five epochs over the entire ~270deg^2^ of Stripe 82, an eventual deep combined map with an rms noise of ~40{mu}Jy and catalogs at a frequency of 3 GHz, and having a spatial resolution of 3". This first paper presents the results from an initial pilot survey of a 50deg^2^ region of Stripe 82, involving four epochs spanning logarithmic timescales between 1 week and 1.5yr, with the combined map having a median rms noise of 35{mu}Jy. This pilot survey enabled the development of the hardware and software for rapid data processing, as well as transient detection and follow-up, necessary for the full 270deg^2^ survey. Data editing, calibration, imaging, source extraction, cataloging, and transient identification were completed in a semi-automated fashion within 6 hr of completion of each epoch of observations, using dedicated computational hardware at the NRAO in Socorro and custom-developed data reduction and transient detection pipelines. Classification of variable and transient sources relied heavily on the wealth of multiwavelength legacy survey data in the Stripe 82 region, supplemented by repeated mapping of the region by the Palomar Transient Factory. A total of 3.9_-0.9_^+0.5^% of the few thousand detected point sources were found to vary by greater than 30%, consistent with similar studies at 1.4 and 5 GHz. Multiwavelength photometric data and light curves suggest that the variability is mostly due to shock-induced flaring in the jets of active galactic nuclei (AGNs). Although this was only a pilot survey, we detected two bona fide transients, associated with an RS CVn binary and a dKe star. Comparison with existing legacy survey data (FIRST, VLA-Stripe 82) revealed additional highly variable and transient sources on timescales between 5 and 20yr, largely associated with renewed AGN activity. The rates of such AGNs possibly imply episodes of enhanced accretion and jet activity occurring once every ~40,000yr in these galaxies. We compile the revised radio transient rates and make recommendations for future transient surveys and joint radio-optical experiments.
- ID:
- ivo://CDS.VizieR/J/A+A/412/657
- Title:
- CO in cooling flow of clusters of galaxies
- Short Name:
- J/A+A/412/657
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of a CO line survey in central cluster galaxies with cooling flows are presented. Cold molecular gas is detected with the IRAM 30m telescope, through CO(1-0) and CO(2-1) emission lines in 6-10 among 32 galaxies. The corresponding gas masses are between 3x10^8^ and 4x10^10^M_{sun}. These results are in agreement with recent CO detections by Edge (2001MNRAS.328..762E). A strong correlation between the CO emission and the H{alpha} luminosity is also confirmed. Cold gas exists in the center of cooling flow clusters and these detections may be interpreted as evidence of the long searched for very cold residual of the hot cooling gas.
- ID:
- ivo://CDS.VizieR/J/ApJ/766/109
- Title:
- Color/age/metallicity gradients of E galaxies
- Short Name:
- J/ApJ/766/109
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In order to understand the past merging history of elliptical galaxies, we studied the optical-near-infrared (NIR) color gradients of 204 elliptical galaxies. These galaxies are selected from the overlap region of the Sloan Digital Sky Survey (SDSS) Stripe 82 and the UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS). The use of optical and NIR data (g, r, and K) provides large wavelength baselines, and breaks the age-metallicity degeneracy, allowing us to derive age and metallicity gradients. The use of the deep SDSS Stripe 82 images makes it possible for us to examine how the color/age/metallicity gradients are related to merging features. We find that the optical-NIR color and the age/metallicity gradients of elliptical galaxies with tidal features are consistent with those of relaxed ellipticals, suggesting that the two populations underwent a similar merging history on average and that mixing of stars was more or less completed before the tidal features disappeared. Elliptical galaxies with dust features have steeper color gradients than the other two types, even after masking out dust features during the analysis, which can be due to a process involving wet merging. More importantly, we find that the scatter in the color/age/metallicity gradients of the relaxed and merging feature types decreases as their luminosities (or masses) increase at M>10^11.4^M_{sun}_ but stays large at lower luminosities. Mean metallicity gradients appear nearly constant over the explored mass range, but a possible flattening is observed at the massive end.
- ID:
- ivo://CDS.VizieR/J/A+A/478/701
- Title:
- Color excess of SDSS quasars with DLA systems
- Short Name:
- J/A+A/478/701
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyzed the spectroscopic and photometric database of the 5th data release of the Sloan Digital Sky Survey (SDSS) to search for evidence of the quasar reddening produced by dust embedded in intervening damped Ly{alpha} (DLA) systems. From a list of 5164 quasars in the interval of emission redshift 2.25<=z_e_<=3.5 and SDSS spectra with signal-to-noise ratio SNR>~4, we built up an "absorption sample" of 248 QSOs with a single DLA system in the interval of absorption redshift 2.2<z_a_<=3.5 and a "pool" of 1959 control QSOs without DLA systems or strong metal systems. For each QSO of the absorption sample we extracted from the pool a subset of control QSOs that are closest in redshift and magnitude.
- ID:
- ivo://CDS.VizieR/J/ApJ/720/368
- Title:
- Color-magnitude relations of galaxies in CDFs
- Short Name:
- J/ApJ/720/368
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extend color-magnitude relations for moderate-luminosity X-ray active galactic nucleus (AGN) hosts and non-AGN galaxies through the galaxy formation epoch (z~1-4) in the Chandra Deep Field-North and Chandra Deep Field-South (CDF-N and CDF-S, respectively; jointly CDFs) surveys. This study was enabled by the deepest available X-ray data from the 2Ms CDF surveys as well as complementary ultradeep multiwavelength data in these regions. We utilized analyses of color-magnitude diagrams (CMDs) to assess the role of moderate-luminosity AGNs in galaxy evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/582/668
- Title:
- Colours and H{alpha} in galaxy pairs
- Short Name:
- J/ApJ/582/668
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy-galaxy interactions rearrange the baryons in galaxies and trigger substantial star formation; the aggregate effects of these interactions on the evolutionary histories of galaxies in the universe are poorly understood. We combine B- and R-band photometry and optical spectroscopy to estimate the strengths and timescales of bursts of triggered star formation in the centers of 190 galaxies in pairs and compact groups. Based on an analysis of the measured colors and EW(H{alpha}), we characterize the preexisting and triggered populations separately. The best-fitting burst scenarios assume stronger reddening corrections for line emission than for the continuum and continuous star formation lasting for >~100Myr. The most realistic scenarios require an initial mass function that is deficient in the highest mass stars. The color of the preexisting stellar population is the most significant source of uncertainty. Triggered star formation contributes substantially (probably >~50%) to the R-band flux in the central regions of several galaxies; tidal tails do not necessarily accompany this star formation. Many of the galaxies in our sample have bluer centers than outskirts, suggesting that pre- or nonmerger interactions may lead to evolution along the Hubble sequence. These objects would appear blue and compact at higher redshifts; the older, redder outskirts of the disks would be difficult to detect. Our data indicate that galaxies with larger separations on the sky contain weaker, and probably older, bursts of star formation on average. However, confirmation of these trends requires further constraints on the colors of the older stellar populations and on the reddening for individual galaxies.
- 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.
