- ID:
- ivo://CDS.VizieR/J/A+A/631/A148
- Title:
- PSZ2 cluster candidates. II.
- Short Name:
- J/A+A/631/A148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The second legacy catalog of Planck Sunyaev-Zeldovich (SZ) sources, hereafter PSZ2, provides the largest galaxy cluster sample selected by means of the SZ signature of the clusters in a full sky survey. In order to fully characterize this PSZ2 sample for cosmological studies, all the members should be validated and the physical properties of the clusters, including mass and redshift, should be derived. However, at the time of its publication, roughly 21% of the 1653 PSZ2 members had no known counterpart at other wavelengths. Here, we present the second and last year of observations of our optical follow-up program 128-MULTIPLE-16/15B (hereafter LP15), which has been developed with the aim of validating all the unidentified PSZ2 sources in the northern sky with declinations higher than -15{deg} that have no correspondence in the first Planck catalog PSZ1. The description of the program and the first year of observations have been presented previously. The LP15 program was awarded 44 observing nights that were spread over two years with the Isaac Newton Telescope (INT), the Telescopio Nazionale Galileo (TNG), and the Gran Telescopio Canarias (GTC), all at Roque de los Muchachos Observatory (La Palma). Following the same method as described previously, we performed deep optical imaging for more than 200 sources with the INT and spectroscopy for almost 100 sources with the TNG and GTC at the end of the LP15 program. We adopted robust confirmation criteria based on velocity dispersion and richness estimates for the final classification of the new galaxy clusters as the optical counterparts of the PSZ2 detections. Here, we present the observations of the second year of LP15, as well as the final results of the program. The full LP15 sample comprises 190 previously unidentified PSZ2 sources. Of these, 106 objects were studied before, while the remaining sample (except for 6 candidates) has been completed in the second year and is discussed here. In addition to the LP15 sample, we here study 42 additional PSZ2 objects that were originally validated as real clusters because they matched a WISE or PSZ1 counterpart, but they had no measured spectroscopic redshift. In total, we confirm the optical counterparts for 81 PSZ2 sources after the full LP15 program, 55 of them with new spectroscopic information. Forty of these 81 clusters are presented in this paper. After the LP15 observational program the purity of the PSZ2 catalog has increased from 76.7% originally to 86.2%. In addition, we study the possible reasons for false detection, and we report a clear correlation between the number of unconfirmed sources and galactic thermal dust emission.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/655/A115
- Title:
- PSZ1 galaxy clusters {sigma} and Mdyn
- Short Name:
- J/A+A/655/A115
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the velocity dispersion and dynamical mass estimates for 270 galaxy clusters included in the first Planck Sunyaev-Zeldovich (SZ) source catalogue, the PSZ1. Part of the results presented here were achieved during a two-year observational program, the ITP, developed at the Roque de los Muchachos Observatory (La Palma, Spain). In the ITP we carried out a systematic optical follow-up campaign of all the 212 unidentified PSZ1 sources in the northern sky that have a declination above -15{deg} and are without known counterparts at the time of the publication of the catalogue. We present for the first time the velocity dispersion and dynamical mass of 58 of these ITP PSZ1 clusters, plus 35 newly discovered clusters that are not associated with the PSZ1 catalogue. Using Sloan Digital Sky Survey archival data, we extend this sample, including 212 already confirmed PSZ1 clusters in the northern sky. Using a subset of 207 of these galaxy clusters, we constrained the M_SZ_-M_dyn_ scaling relation, finding a mass bias of (1-B)=0/83+/-0.07(stat)+/-0.02(sys). We show that this value is consistent with other results in the literature that were obtained with different methods (X-ray, dynamical masses, or weak-lensing mass proxies). This result cannot dissolve the tension between primordial cosmic microwave background anisotropies and cluster number counts in the {OMEGA}_M_-{sigma}8 plane.
- ID:
- ivo://CDS.VizieR/J/ApJS/227/11
- Title:
- PS1 z>5.6 quasars follow-up
- Short Name:
- J/ApJS/227/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Luminous quasars at z>5.6 can be studied in detail with the current generation of telescopes and provide us with unique information on the first gigayear of the universe. Thus far, these studies have been statistically limited by the number of quasars known at these redshifts. Such quasars are rare, and therefore, wide-field surveys are required to identify them, and multiwavelength data are required to separate them efficiently from their main contaminants, the far more numerous cool dwarfs. In this paper, we update and extend the selection for the z~6 quasars presented in Banados+ (2014AJ....148...14B) using the Pan-STARRS1 (PS1) survey. We present the PS1 distant quasar sample, which currently consists of 124 quasars in the redshift range 5.6<~z<~6.7 that satisfy our selection criteria. Of these quasars, 77 have been discovered with PS1, and 63 of them are newly identified in this paper. We present the composite spectra of the PS1 distant quasar sample. This sample spans a factor of ~20 in luminosity and shows a variety of emission line properties. The number of quasars at z>5.6 presented in this work almost doubles the previously known quasars at these redshifts, marking a transition phase from studies of individual sources to statistical studies of the high-redshift quasar population, which was impossible with earlier, smaller samples.
- ID:
- ivo://CDS.VizieR/J/ApJ/776/136
- Title:
- QPQ VI. HI absorption of z~2 quasars
- Short Name:
- J/ApJ/776/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With close pairs of quasars at different redshifts, a background quasar sightline can be used to study a foreground quasar's environment in absorption. We use a sample of 650 projected quasar pairs to study the HI Ly{alpha} absorption transverse to luminous, z~2 quasars at proper separations of 30kpc<R_{perp}_<1Mpc. In contrast to measurements along the line-of-sight, regions transverse to quasars exhibit enhanced HI Ly{alpha} absorption and a larger variance than the ambient intergalactic medium, with increasing absorption and variance toward smaller scales. Analysis of composite spectra reveals excess absorption characterized by a Ly{alpha} equivalent width profile W=2.3{AA} (R_{perp}_/100kpc)^-0.46^. We also observe a high (=~60%) covering factor of strong, optically thick HI absorbers (HI column N_HI_>10^17.3^/cm2) at separations R_{perp}_<200kpc, which decreases to ~20% at R_{perp}_=~1Mpc, but still represents a significant excess over the cosmic average. This excess of optically thick absorption can be described by a quasar-absorber cross-correlation function {xi}_QA_(r)=(r/r_0_)^{gamma}^ with a large correlation length r_0_=12.5_-1.4_^+2.7^h^-1^Mpc (comoving) and {gamma}=1.68_-0.30_^+0.14^. The HI absorption measured around quasars exceeds that of any previously studied population, consistent with quasars being hosted by massive dark matter halos M_halo_{approx}10^12.5^M_{sun}_ at z~2.5. The environments of these massive halos are highly biased toward producing optically thick gas, and may even dominate the cosmic abundance of Lyman limit systems and hence the intergalactic opacity to ionizing photons at z~2.5. The anisotropic absorption around quasars implies the transverse direction is much less likely to be illuminated by ionizing radiation than the line-of-sight.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A144
- Title:
- QSO candidates catalog with APOP & ALLWISE (QCC)
- Short Name:
- J/A+A/618/A144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Quasars are spatially stationary, and they are essential objects in astrometry when defining reference frames. However, the census of quasars is far from complete. Mid-infared colors can be used to find quasar candidates because AGNs show a peculiar appearance in mid-infrared color, but these methods are incapable of separating quasars from AGNs.The aim of our study is to use astrometric and mid-infrared methods to select quasars and get a reliable quasar candidates catalog. We used a near-zero proper motion criterion in conjuction with WISE (all-sky Wide-field Infrared Survey Explorer) [W1-W2] color to select quasar candidates. The [W1-W2] color criterion is defined by the linear boundary of two samples: LAMOST DR5 quasars, which serve as the quasar sample, and LAMOST DR5 stars/galaxies, which serve as the non-quasar sample. The contamination and completeness are evaluated. We present a catalog of 662753 quasar candidates, with a completeness of about 75% and a reliability of 77.2%.
- ID:
- ivo://CDS.VizieR/J/ApJ/508/200
- Title:
- QSO low-z Ly{alpha} absorbers
- Short Name:
- J/ApJ/508/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To study the nature of low-z Ly{alpha} absorbers in the spectra of QSOs, we have obtained high signal-to-noise ratio (S/N) UV spectra of H1821+643 (z_em_=0.297) and PG 1116+215 (z_em_=0.177) with the Goddard High-Resolution Spectrograph on the Hubble Space Telescope.
- ID:
- ivo://CDS.VizieR/J/ApJ/710/1498
- Title:
- QSO luminosity function at z~4
- Short Name:
- J/ApJ/710/1498
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution of the quasar luminosity function (QLF) is one of the basic cosmological measures providing insight into structure formation and mass assembly in the universe. We have conducted a spectroscopic survey to find faint quasars (-26.0<M_1450_<-22.0) at redshifts z=3.8-5.2 in order to measure the faint end of the QLF at these early times. Using available optical imaging data from portions of the NOAO Deep Wide-Field Survey and the Deep Lens Survey, we have color-selected quasar candidates in a total area of 3.76deg^2^. Thirty candidates have R<=23mag. We conducted spectroscopic follow-up for 28 of our candidates and found 23 QSOs, 21 of which are reported here for the first time, in the 3.74<z<5.06 redshift range.
978. QSOs CaII absorbers
- ID:
- ivo://CDS.VizieR/J/A+A/528/A12
- Title:
- QSOs CaII absorbers
- Short Name:
- J/A+A/528/A12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic study of weak intervening CaII absorbers at low redshift (z<0.5), based on the analysis of archival high-resolution (R>=45000) optical spectra of 304 quasars and active galactic nuclei observed with VLT/UVES. Along a total redshift path of {DELTA}z~~100 we detected 23 intervening CaII absorbers in both the CaII H & K lines, with rest frame equivalent widths W_r,3934_=15-799m{AA} and column densities logN(CaII)=11.25-13.04 (obtained by fitting Voigt-profile components).
979. QSOs in the M3 field
- ID:
- ivo://CDS.VizieR/J/A+A/392/851
- Title:
- QSOs in the M3 field
- Short Name:
- J/A+A/392/851
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a variability and proper motion (VPM) search for QSOs in the field around M3. The VPM search is demonstrated to be powerful technique for efficiently finding QSOs without major selection effects with regard to the spectral energy distribution. Remarkably, the properties of the VPM QSOs do not significantly differ from those of samples from more conventional optical search techniques. The lightcurves of the QSOs from the resulting sample provide an interesting data set for the statistical investigation of QSO long-term variability.
- ID:
- ivo://CDS.VizieR/J/AJ/107/1245
- Title:
- QSOs Palomar Transit Grism Survey catalog
- Short Name:
- J/AJ/107/1245
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports the initial results of the Palomar Transit Grism Survey (PTGS). The PTGS was designed to produce a sample of z>2.7 quasars that were identified by well-defined selection criteria. The survey consists of six narrow (~8.5' wide) strips of sky; the total effective area is 61.47deg^2^. Low-resolution slitless spectra, covering the wavelength range from 4400 to 7500A, were obtained for approximately 600000 objects. The wavelength- and flux-calibrated spectra were searched for emission lines with an automatic software algorithm. A total to 1655 emission features in the grism data satisfied our signal-to-noise ratio and equivalent width selection criteria; subsequent slit spectroscopy of the candidates confirmed the existence of 1052 lines (928 different objects). Six groups of emission lines were detected in the survey: Lyman alpha+N V, C IV, C III], Mg II, Hbeta+[O III], and Halpha+[S II]. More than two-thirds of the candidates are low-redshift (z<0.45) emission-line galaxies; ninety objects are high-redshift quasars (z>2.7) detected via their Lyman alpha+N V emission lines. The survey contains three previously unknown quasars brighter than 17th magnitude; all three have redshifts of ~1.3. In this paper we present the observational properties of the survey, the algorithms used to select the emission-line candidates, and the catalog of emission-line objects.