- ID:
- ivo://CDS.VizieR/J/ApJ/365/66
- Title:
- Redshifts of a sample of distant Abell clusters
- Short Name:
- J/ApJ/365/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured redshifts for a complete sample of 145 Abell clusters of galaxies. The sample covers a 561 square degree region at high Galactic latitude. The median redshift of the clusters in the sample is 0.16. For R >= 1 clusters the correlation length is r_0_ = 21 h^-1^ Mpc. The amplitude of the correlation function is a factor of 1.4 less than that obtained by Bahcall and Soneira, but the difference is within the 1 {sigma} uncertainties. In this sample we cannot detect clustering on scales >~ 70 h^-1^ Mpc. Although the maps of the cluster distribution in redshift space show a large void of diameter ~20,000 km s^-1^, frequent occurrence of such large empty regions is consistent with the smaller scale behaviour of the correlation function of the survey. Large-scale peculiar motions are <~1000 km s^-1^. This limit is inconsistent with the claim of detection by Bahcall, Soneira, and Burgett of ~2000 km/s peculiar motions. We suggest that the earlier result is affected by the Corona Borealis supercluster, which contributes more than a third of the excess pairs in the shallower survey.
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- ID:
- ivo://CDS.VizieR/J/AJ/123/100
- Title:
- Redshifts of AWM and MKW poor clusters
- Short Name:
- J/AJ/123/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured 1365 redshifts to a limiting magnitude of R~15.5 in 15 AWM/MKW clusters and have collected another 203 from the literature in MKW 4s, MKW 2, and MKW 2s. In AWM 7 we have extended the redshift sample to R~18 in the cluster center. We have identified 704 cluster members in 17 clusters; 201 are newly identified. We summarize the kinematics and distributions of the cluster galaxies and provide an initial discussion of substructure, mass and luminosity segregation, spectral segregation, velocity-dispersion profiles, and the relation of the central galaxy to global cluster properties. We compute optical mass estimates, which we compare with X-ray mass determinations from the literature.
- ID:
- ivo://CDS.VizieR/J/ApJ/780/73
- Title:
- Redshifts of BL Lac objects from Fermi
- Short Name:
- J/ApJ/780/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Fermi has provided the largest sample of {gamma}-ray-selected blazars to date. In this work we use a uniformly selected set of 211 BL Lacertae (BL Lac) objects detected by Fermi during its first year of operation. We obtained redshift constraints for 206 out of the 211 BL Lac objects in our sample, making it the largest and most complete sample of BL Lac objects available in the literature. We use this sample to determine the luminosity function of BL Lac objects and its evolution with cosmic time. We find that for most BL Lac classes the evolution is positive, with a space density peaking at modest redshift (z{approx}1.2). Low-luminosity, high-synchrotron-peaked (HSP) BL Lac objects are an exception, showing strong negative evolution, with number density increasing for z<~0.5. Since this rise corresponds to a drop-off in the density of flat-spectrum radio quasars (FSRQs), a possible interpretation is that these HSPs represent an accretion-starved end state of an earlier merger-driven gas-rich phase. We additionally find that the known BL Lac correlation between luminosity and photon spectral index persists after correction for the substantial observational selection effects with implications for the so-called "blazar sequence." Finally, by estimating the beaming corrections to the luminosity function, we find that BL Lac objects have an average Lorentz factor of {gamma}=6.1_-0.8_^+1.1^, and that most are seen within 10{deg} of the jet axis.
- ID:
- ivo://CDS.VizieR/J/AJ/148/13
- Title:
- Redshifts of 65 CANDELS supernovae
- Short Name:
- J/AJ/148/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) was a multi-cycle treasury program on the Hubble Space Telescope (HST) that surveyed a total area of ~0.25deg^2^ with ~900 HST orbits spread across five fields over three years. Within these survey images we discovered 65 supernovae (SNe) of all types, out to z~2.5. We classify ~24 of these as Type Ia SNe (SNe Ia) based on host galaxy redshifts and SN photometry (supplemented by grism spectroscopy of six SNe). Here we present a measurement of the volumetric SN Ia rate as a function of redshift, reaching for the first time beyond z=2 and putting new constraints on SN Ia progenitor models. Our highest redshift bin includes detections of SNe that exploded when the universe was only ~3Gyr old and near the peak of the cosmic star formation history. This gives the CANDELS high redshift sample unique leverage for evaluating the fraction of SNe Ia that explode promptly after formation (<500Myr). Combining the CANDELS rates with all available SN Ia rate measurements in the literature we find that this prompt SN Ia fraction is f_p_=0.53_stat0.10sys0.26_^+/-0.09 +/-0.10^, consistent with a delay time distribution that follows a simple t^-1^ power law for all times t>40Myr. However, mild tension is apparent between ground-based low-z surveys and space-based high-z surveys. In both CANDELS and the sister HST program CLASH (Cluster Lensing And Supernova Survey with Hubble), we find a low rate of SNe Ia at z>1. This could be a hint that prompt progenitors are in fact relatively rare, accounting for only 20% of all SN Ia explosions--though further analysis and larger samples will be needed to examine that suggestion.
- ID:
- ivo://CDS.VizieR/J/A+A/427/397
- Title:
- Redshifts of 5 EDisCS galaxy clusters
- Short Name:
- J/A+A/427/397
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic observations are presented for objects in the fields of 4 galaxy clusters at z=0.7-0.8 (Cl 1040.7-1155 (Cl 1040), Cl 1054.4-1146 (Cl 1054-11), Cl 1054.7-1245 (Cl 1054-12), and Cl 1216.8-1201 (Cl 1216)) and in one cluster at z~0.5 (Cl 1232.5-1250 (Cl 1232)) of the ESO Distant Cluster Survey (EDisCS). We present tables of RA and DE positions for an equinox of 2000 (J2000, epoch 2001), I-band magnitudes for an aperture of radius 1 arcsecond, spectroscopic redshifts for objects in the fields of our 5 clusters, and membership and targeting flags to indicate whether the object is a cluster member and/or was targeted to be a cluster member respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/409/439
- Title:
- Redshifts of 11 EIS clusters
- Short Name:
- J/A+A/409/439
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of carrying out multi-object spectroscopy in 10 EIS cluster fields. Based on the list of 345 galaxy redshifts we identify significant 3D-density enhancements. For 9 of the EIS clusters we identify significant 3D-concentrations corresponding to the originally detected cluster candidate. We find redshifts in the range 0.097<=z<=0.257 which is in good agreement with the matched filter estimate of z_MF_=0.2. We estimate velocity dispersions in the range 219-1160km/s for the confirmed clusters
- ID:
- ivo://CDS.VizieR/J/A+A/388/1
- Title:
- Redshifts of five EIS clusters
- Short Name:
- J/A+A/388/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of the first multi-object spectroscopic observations at the Danish 1.54m telescope at La Silla, Chile. Observations of five cluster candidates from The ESO Imaging Survey Cluster Candidate Catalog are described. From these observations we confirm the reality of the five clusters with measured redshifts of 0.11<=z<=0.35. We estimate velocity dispersions in the range 294-621km/s indicating rather poor clusters. This, and the measured cluster redshifts are consistent with the results of the matched filter procedure applied to produce the Cluster Candidate Catalog.
- ID:
- ivo://CDS.VizieR/J/A+A/468/807
- Title:
- Redshifts of galaxies associated with X emission
- Short Name:
- J/A+A/468/807
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopic observations of galaxies associated with the diffuse X-ray emitting structure discovered by Zappacosta et al. (2002A&A...394....7Z). After measuring the redshifts of 161 galaxies, we confirm an overdensity of galaxies with projected dimensions of at least 2Mpc, determine its spectroscopic redshift in z=0.401+/-0.002, and show that it is spatially coincident with the diffuse X-ray emission. This confirms the original claim that this X-ray emission has an extragalactic nature and is due to the warm-hot intergalactic medium (WHIM). We used this value of the redshift to compute the temperature of the emitting gas. The resulting value depends on the metallicity that is assumed for the IGM, and is constrained to be between 0.3 and 0.6keV for metallicities between 0.05 and 0.3solar, in good agreement with the expectations from the WHIM.
- ID:
- ivo://CDS.VizieR/J/ApJ/781/2
- Title:
- Redshifts of 1151 galaxies from SDSS
- Short Name:
- J/ApJ/781/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lines of sight with multiple projected cluster-scale gravitational lenses have high total masses and complex lens plane interactions that can boost the area of magnification, or etendue, making detection of faint background sources more likely than elsewhere. To identify these new "compound" cosmic telescopes, we have found directions in the sky with the highest integrated mass densities, as traced by the projected concentrations of luminous red galaxies (LRGs). We use new galaxy spectroscopy to derive preliminary magnification maps for two such lines of sight with total mass exceeding ~3x10^15^M_{sun}_. From 1151 MMT Hectospec spectra of galaxies down to i_AB_=21.2, we identify two to three group- and cluster-scale halos in each beam. These are well traced by LRGs. The majority of the mass in beam J085007.6+360428 (0850) is contributed by Zwicky 1953, a massive cluster at z=0.3774, whereas beam J130657.5+463219 (1306) is composed of three halos with virial masses of 6x10^14^-2x10^15^M_{sun}_, one of which is A1682. The magnification maps derived from our mass models based on spectroscopy and Sloan Digital Sky Survey photometry alone display substantial etendue: the 68% confidence bands on the lens plane area with magnification exceeding 10 for a source plane of z_s_=10 are [1.2,3.8]arcmin^2^ for 0850 and [2.3,6.7]arcmin^2^ for 1306. In deep Subaru Suprime-Cam imaging of beam 0850, we serendipitously discover a candidate multiply imaged V-dropout source at z_phot_=5.03. The location of the candidate multiply imaged arcs is consistent with the critical curves for a source plane of z=5.03 predicted by our mass model. Incorporating the position of the candidate multiply imaged galaxy as a constraint on the critical curve location in 0850 narrows the 68% confidence band on the lens plane area with {mu}>10 and z_s_=10 to [1.8,4.2]arcmin^2^, an etendue range comparable to that of MACS 0717+3745 and El Gordo, two of the most powerful single cluster lenses known. The significant lensing power of our beams makes them powerful probes of reionization and galaxy formation in the early universe.
- ID:
- ivo://CDS.VizieR/J/A+A/425/429
- Title:
- Redshifts of 119 galaxies in ACO 1367
- Short Name:
- J/A+A/425/429
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Redshifts of 119 galaxies in the Abell cluster 1367 are presented. The majority (98) were obtained with the AF2-WYFFOS multi fiber spectrograph at the 4.2m William Herschel Telescope (WHT). Nine additional long-slit, low dispersion spectra were obtained using the imaging spectrograph BFOSC attached to the Cassini 1.5m telescope at Loiano. Another twelve spectra were taken with LFOSC at the 2.1m telescope of the Guillermo Haro Observatory at Cananea.
