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741. Rc-band light curves of 6 lensed QSOs
ID:
ivo://CDS.VizieR/J/A+A/642/A193
Title:
Rc-band light curves of 6 lensed QSOs
Short Name:
J/A+A/642/A193
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present six new time-delay measurements obtained from Rc-band monitoring data acquired at the MPIA 2.2m telescope at La Silla observatory between October 2016 and February 2020. The lensed quasars HE 0047-1756, WG 0214-2105, DES 0407-5006, 2M 1134-2103, PSJ 1606-2333 and DES 2325-5229 were observed almost daily at high signal-to-noise ratio to obtain high-quality light curves where we can record fast and small-amplitude variations of the quasars. We measure time delays between all pairs of multiple images with only one or two seasons of monitoring at the exception of the time delays relative to image D of PSJ 1606-2333. The most precise estimate is obtained for the delay between image A and image B of DES 0407-5006, with {tau}_AB_=-128.4^+3.5^_-3.8_ days (2.8% precision) including systematics due to extrinsic variability in the light curves. For HE 0047-1756, we combine our high-cadence data with measurements from decade-long light-curves from previous COSMOGRAIL campaigns, and reach a precision of 0.9 day on the final measurement. The present work demonstrates the feasibility of measuring time delays in lensed quasars in only one or two seasons, provided high signal-to-noise ratio data are obtained at a cadence close to daily.
742. Reddening curve of IRAS 14026+4341
ID:
ivo://CDS.VizieR/J/AJ/145/157
Title:
Reddening curve of IRAS 14026+4341
Short Name:
J/AJ/145/157
Date:
21 Oct 2021
Publisher:
CDS
Description:
A fraction of the heavily reddened quasars require a reddening curve that is even steeper than that of the Small Magellanic Cloud. In this paper, we thoroughly characterize the anomalously steep reddening law in quasars via an exceptional example observed in IRAS14026+4341. By comparing the observed spectrum to the quasar composite spectrum, we derive a reddening curve in the rest-frame wavelength range of 1200-10000{AA}. It has a steep rise at wavelengths shorter than 3000{AA}, but no significant reddening at longer wavelengths. The absence of dust reddening in the optical continuum is confirmed by the normal broad-line Balmer decrement (the H{alpha}/H{beta} ratio) in IRAS14026+4341. The anomalous reddening curve can be satisfactorily reproduced with a dust model containing silicate grains in a power-law size distribution, dn(a)/da{prop.to}a^-1.4^, truncated at a maximum size of a_max_=70nm. The unusual size distribution may be caused by the destruction of large "stardust" grains by quasar activities or a different dust formation mechanism (i.e., the in situ formation of dust grains in quasar outflows). It is also possible that the analogies of the dust grains observed near the Galactic center are responsible for the steep reddening curve. In addition, we find that IRAS14026+4341 is a weak emission-line quasar (i.e., PHL1811 analogies) with heavy dust reddening and blueshifted broad absorption lines.
743. Reddening of ~35000 quasars from SDSS
ID:
ivo://CDS.VizieR/J/AJ/149/203
Title:
Reddening of ~35000 quasars from SDSS
Short Name:
J/AJ/149/203
Date:
21 Oct 2021
Publisher:
CDS
Description:
We explore the extinction/reddening of ~35000 uniformly selected quasars with 0<z{<=}5.3 in order to better understand their intrinsic optical/ultraviolet (UV) spectral energy distributions. Using rest-frame optical-UV photometry taken from the Sloan Digital Sky Survey's (SDSS) 7th data release, cross-matched to WISE in the mid-infrared, 2MASS and UKIDSS in the near-infrared, and GALEX in the UV, we isolate outliers in the color distribution and find them well described by an SMC-like reddening law. A hierarchical Bayesian model with a Markov Chain Monte Carlo sampling method was used to find distributions of power law indices and E(B-V) consistent with both the broad absorption line (BAL) and non-BAL samples. We find that, of the ugriz color-selected type 1 quasars in SDSS, 2.5% (13%) of the non-BAL (BAL) sample are consistent with E(B-V)>0.1 and 0.1% (1.3%) with E(B-V)>0.2. Simulations show both populations of quasars are intrinsically bluer than the mean composite, with a mean spectral index ({alpha}_{lambda}_) of -1.79 (-1.83). The emission and absorption-line properties of both samples reveal that quasars with intrinsically red continua have narrower Balmer lines and stronger high-ionization emission lines, the latter indicating a harder continuum in the extreme-UV and the former pointing to differences in black hole mass and/or orientation.
744. Redshift catalog of HE 0435-1223 field-of-view
ID:
ivo://CDS.VizieR/J/MNRAS/470/4838
Title:
Redshift catalog of HE 0435-1223 field-of-view
Short Name:
J/MNRAS/470/4838
Date:
21 Oct 2021
Publisher:
CDS
Description:
Galaxies located in the environment or along the line of sight towards gravitational lenses can significantly affect lensing observables, and can lead to systematic errors on the measurement of H_0_ from the time-delay technique. We present the results of a systematic spectroscopic identification of the galaxies in the field of view of the lensed quasar HE 0435-1223 using the W.M. Keck, Gemini and ESO-Very Large telescopes. Our new catalogue triples the number of known galaxy redshifts in the direct vicinity of the lens, expanding to 102 the number of measured redshifts for galaxies separated by less than 3 arcmin from the lens. We complement our catalogue with literature data to gather redshifts up to 15 arcmin from the lens, and search for galaxy groups or clusters projected towards HE 0435-1223. We confirm that the lens is a member of a small group that includes at least 12 galaxies, and find 8 other group candidates near the line of sight of the lens. The flexion shift, namely the shift of lensed images produced by high-order perturbation of the lens potential, is calculated for each galaxy/group and used to identify which objects produce the largest perturbation of the lens potential. This analysis demonstrates that (i) at most three of the five brightest galaxies projected within 12 arcsec of the lens need to be explicitly used in the lens models, and (ii) the groups can be treated in the lens model as an external tidal field (shear) contribution.
745. Redshift dependence of BAL QSOs
ID:
ivo://CDS.VizieR/J/MNRAS/410/860
Title:
Redshift dependence of BAL QSOs
Short Name:
J/MNRAS/410/860
Date:
21 Oct 2021
Publisher:
CDS
Description:
We describe the application of non-negative matrix factorization to generate compact reconstructions of quasar spectra from the Sloan Digital Sky Survey (SDSS), with particular reference to broad absorption line quasars (BALQSOs). BAL properties are measured for SiIV{lambda}1400, CIV{lambda}1550, AlIII{lambda}1860 and MgII{lambda}2800, resulting in a catalogue of 3547 BALQSOs. Two corrections, based on extensive testing of synthetic BALQSO spectra, are applied in order to estimate the intrinsic fraction of CIV BALQSOs. First, the probability of an observed BALQSO spectrum being identified as such by our algorithm is calculated as a function of redshift, signal-to-noise ratio and BAL properties. Secondly, the different completenesses of the SDSS target selection algorithm for BALQSOs and non-BAL quasars are quantified.
746. Redshifts for X-ray selected AGNs
ID:
ivo://CDS.VizieR/J/A+A/434/475
Title:
Redshifts for X-ray selected AGNs
Short Name:
J/A+A/434/475
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present photometric redshift estimates for X-ray selected sources detected in the XMM/2dF survey. 5-band photometry for 193 sources has been obtained from the SDSS. We exclude 10 sources associated with Galactic stars. The tabulated data include the optical coordinate of all sources in our sample, their photometric redshift estimate, their r-band magnitude and g-r colour as well as their morphological classification (these optical parameters have been used in the discussion of our results). Spectroscopic redshifts are available only for a sub-sample of our data and are included in Table 1 together with the survey from which they have been obtained.
747. Redshifts in the SFQS survey
ID:
ivo://CDS.VizieR/J/AJ/131/2788
Title:
Redshifts in the SFQS survey
Short Name:
J/AJ/131/2788
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present the first results of a deep spectroscopic survey of faint quasars in the Sloan Digital Sky Survey (SDSS) Southern Survey, a deep survey carried out by repeatedly imaging a 270{deg}^2^ area. Quasar candidates were selected from the deep data with good completeness over 0<z<5 and 2-3mag fainter than the SDSS main survey. Spectroscopic follow-up was carried out on the 6.5m MMT with Hectospec. The preliminary sample of this SDSS faint quasar survey (SFQS) covers ~3.9{deg}^2^, contains 414 quasars, and reaches g=22.5.
748. Redshifts of damped Lyman{alpha} absorbers
ID:
ivo://CDS.VizieR/J/MNRAS/346/1103
Title:
Redshifts of damped Lyman{alpha} absorbers
Short Name:
J/MNRAS/346/1103
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a study of the evolution of the column density distribution, f(N,z), and total neutral hydrogen mass in high column density quasar absorbers using candidates from a recent high-redshift survey for damped Lyman{alpha} (DLA) and Lyman-limit system (LLS) absorbers.
749. Redshift survey in 15 quasar fields
ID:
ivo://CDS.VizieR/J/MNRAS/367/1261
Title:
Redshift survey in 15 quasar fields
Short Name:
J/MNRAS/367/1261
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the relative distribution of the gaseous contents of the Universe (as traced by a sample of Ly{alpha} absorbers), and the luminous baryonic matter (as traced by a redshift survey of galaxies in the same volume searched for Ly{alpha} absorbers), along 16 lines of sight (LOS) between redshifts 0 and 1. Our galaxy redshift survey was made with the multi-object spectrograph on the Canada-France-Hawaii Telescope and, when combined with galaxies from the literature in the same LOS, gives us a galaxy sample of 636 objects. By combining this with an absorption-line sample of 406 absorbing systems drawn from published works, we are able to study the relationship between gas and galaxies over the latter half of the age of the Universe.
750. Relativistic jets from black hole systems
ID:
ivo://CDS.VizieR/J/other/Sci/338.1445
Title:
Relativistic jets from black hole systems
Short Name:
J/other/Sci/338.
Date:
21 Oct 2021
Publisher:
CDS
Description:
Black holes generate collimated, relativistic jets, which have been observed in {gamma}-ray bursts (GRBs), microquasars, and at the center of some galaxies [active galactic nuclei (AGN)]. How jet physics scales from stellar black holes in GRBs to the supermassive ones in AGN is still unknown. Here, we show that jets produced by AGN and GRBs exhibit the same correlation between the kinetic power carried by accelerated particles and the {gamma}-ray luminosity, with AGN and GRBs lying at the low- and high-luminosity ends, respectively, of the correlation. This result implies that the efficiency of energy dissipation in jets produced in black hole systems is similar over 10 orders of magnitude in jet power, establishing a physical analogy between AGN and GRBs.