- 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.
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- ID:
- ivo://CDS.VizieR/J/A+AS/123/219
- Title:
- The B3-VLA Quasar Sample
- Short Name:
- J/A+AS/123/219
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new low frequency radio selected Sample of 125 Quasars complete down to 100mJy at 408MHz is presented in this paper. The sample is a part of the B3-VLA sample: 1050 radiosources selected from the B3 catalogue at 408MHz and observed at the VLA (1465MHz, C and A configurations). Out of the 352 sources, identified on the POSS-I down to m_r_~20.0, 172 are quasar candidates. In this paper we give the final assessment of the quasar sample from spectroscopic observations of the candidates. The final complete quasar sample consists of 125 objects. Furthermore 3 Bl Lac objects have been identified and two Bl Lac candidates.
- 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/MNRAS/326/1455
- Title:
- The CLASS blazar survey. I.
- Short Name:
- J/MNRAS/326/1455
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents a new complete and well-defined sample of flat-spectrum radio sources (FSRS) selected from the Cosmic Lens All-Sky Survey (CLASS), with the further constraint of a bright (mag<=17.5) optical counterpart. The sample has been designed to produce a large number of low-luminosity blazars in order to test the current unifying models in the low-luminosity regime. In this first paper the new sample is presented and the radio properties of the 325 sources contained therein are discussed.
- ID:
- ivo://CDS.VizieR/J/MNRAS/329/877
- Title:
- The CLASS blazar survey. II.
- Short Name:
- J/MNRAS/329/877
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the optical properties of the objects selected in the CLASS blazar survey. Because an optical spectrum is now available for 70 per cent of the 325 sources present in the sample, a spectral classification, based on the appearance of the emission/absorption lines, is possible. A wide variety of optical spectral types is found. Besides `classical' BL Lacs (42), BL Lac candidates (5) and high-power (P_5GHz_>10^26^W/Hz) flat spectrum radio quasars (67), a significant number of `passive' elliptical galaxies (41) is also found. Moreover, 33 broad emission line objects with a low radio power (P(5GHz)>10^26^W/Hz) are discovered, suggesting that at least a fraction (~24-30 per cent) of low-power blazars have a broad line region. Finally, 34 objects showing only narrow emission lines, either as a result of some starburst activity in the host galaxy or as a result of the presence of an active galactic nucleus, appear in the sample.
- ID:
- ivo://CDS.VizieR/J/MNRAS/348/937
- Title:
- The CLASS blazar survey. III.
- Short Name:
- J/MNRAS/348/937
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss the properties of the sources in the CLASS blazar survey, which aims at the selection of low radio power (P_5GHz_<10^25^W/Hz) blazars. We use Very Large Array (VLA) data from available catalogues and from our own observations to constrain the radio core-dominance of the sample which, together with the flat radio spectral index, is a signature of the blazar activity. X-ray data from the ROSAT All Sky Survey were also collected in order to constrain the radio-to-X-ray luminosity ratio of the sources.
- ID:
- ivo://CDS.VizieR/J/ApJ/866/33
- Title:
- The COS CGM compendium. I. Initial results
- Short Name:
- J/ApJ/866/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a neutral hydrogen-selected absorption-line survey of gas with HI column densities 15<logN_HI_<19 at z<~1 using the Cosmic Origins Spectrograph on the Hubble Space Telescope. Our main aim is to determine the metallicity distribution of these absorbers. Our sample consists of 224 absorbers selected on the basis of their HI absorption strength. Here we discuss the properties of our survey and the immediate empirical results. We find singly and doubly ionized metal species, and HI typically have similar velocity profiles, implying they probe gas in the same or similar environments. The ionic ratios (e.g., N_CII_/N_CIII_, N_OI_/N_CII_) indicate that the gas in these absorbers is largely ionized, and the ionization conditions are quite comparable across the sampled N_HI_ range. The Doppler parameters of the HI imply T<~5x10^4^K on average, consistent with the gas being photoionized. The MgII column densities span >2 orders of magnitude at any given N_HI_, indicating a wide range of metallicities (from solar to <1/100 solar). In the range of 16.2<~logN_HI_<~17, there is a gap in the N_MgII_ distribution corresponding to gas with ~10% solar metallicity, consistent with the gap seen in the previously identified bimodal metallicity distribution in this column density regime. Less than 3% of the absorbers in our sample show no detectable metal absorption, implying that truly pristine gas at z<~1 is uncommon. We find <[FeII/MgII]>=-0.4+/-0.3, and since {alpha}-enhancement can affect this ratio, dust depletion is extremely mild.
- ID:
- ivo://CDS.VizieR/VII/241
- Title:
- The 2dF QSO Redshift Survey
- Short Name:
- VII/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The final catalogue of the 2dF QSO Redshift Survey (2QZ) is based on Anglo-Australian Telescope 2dF spectroscopic observations of 44576 colour-selected (ub_J_r) objects with 18.25<b_J_< 20.85 selected from automated plate measurement scans of UK Schmidt Telescope (UKST) photographic plates. The 2QZ comprises 23338 quasi-stellar objects (QSOs), 12292 galactic stars (including 2071 white dwarfs) and 4558 compact narrow emission-line galaxies. We obtained a reliable spectroscopic identification for 86 per cent of objects observed with 2dF. We also report on the 6dF QSO Redshift Survey (6QZ), based on UKST 6dF observations of 1564 brighter (16<b_J_<18.25) sources selected from the same photographic input catalogue. In total, we identified 322 QSOs spectroscopically in the 6QZ. The completed 2QZ is, by more than a factor of 50, the largest homogeneous QSO catalogue ever constructed at these faint limits (b_J_<20.85) and high QSO surface densities (35 QSOs/deg^2^). As such, it represents an important resource in the study of the Universe at moderate-to-high redshifts.
- ID:
- ivo://CDS.VizieR/J/MNRAS/328/805
- Title:
- The 2dF QSO Redshift Survey. VIII
- Short Name:
- J/MNRAS/328/805
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the highest signal-to-noise ratio spectra from the 2dF QSO Redshift Survey (2QZ) 10k release (Cat. <VII/223>) and identify over 100 new low-ionization heavy-element absorbers: damped Lyman-{alpha} (DLA) candidates suitable for higher-resolution follow-up observations. These absorption systems map the spatial distribution of high-z metals in exactly the same volumes as the foreground 2QZ QSOs themselves sample and hence the 2QZ gives us the unique opportunity to compare directly the two tracers of large-scale structure. We examine the cross-correlation of the two populations to see how they are relatively clustered, and, by considering the colour of the QSOs, detect a small amount of dust in these metal systems.
- ID:
- ivo://CDS.VizieR/VII/223
- Title:
- The 2dF QSO Redshift Survey. V. The 10k catalogue
- Short Name:
- VII/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 2dF QSO Redshift Survey (2QZ) 10k catalogue is the first release of the 2QZ, containing over 10000 QSOs. There are a total of 20590 sources listed, for which spectra have been obtained using the 2-degree field facility at the Anglo-Australian Observatory. Current data covers an effective area of 289.6deg^2^ for QSO candidates with magnitudes 18.25<b_J_<20.85. The file 2qz_10k.dat contains the names, positions, magnitudes, spectroscopic identifications and redshifts for each of the sources.
