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1361. 27 pulsating DA WDs follow-up observations
ID:
ivo://CDS.VizieR/J/ApJS/232/23
Title:
27 pulsating DA WDs follow-up observations
Short Name:
J/ApJS/232/23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present photometry and spectroscopy for 27 pulsating hydrogen-atmosphere white dwarfs (DAVs; a.k.a. ZZ Ceti stars) observed by the Kepler space telescope up to K2 Campaign 8, an extensive compilation of observations with unprecedented duration (>75 days) and duty cycle (>90%). The space-based photometry reveals pulsation properties previously inaccessible to ground- based observations. We observe a sharp dichotomy in oscillation mode line widths at roughly 800s, such that white dwarf pulsations with periods exceeding 800s have substantially broader mode line widths, more reminiscent of a damped harmonic oscillator than a heat-driven pulsator. Extended Kepler coverage also permits extensive mode identification: we identify the spherical degree of 87 out of 201 unique radial orders, providing direct constraints of the rotation period for 20 of these 27 DAVs, more than doubling the number of white dwarfs with rotation periods determined via asteroseismology. We also obtain spectroscopy from 4m-class telescopes for all DAVs with Kepler photometry. Using these homogeneously analyzed spectra, we estimate the overall mass of all 27 DAVs, which allows us to measure white dwarf rotation as a function of mass, constraining the endpoints of angular momentum in low- and intermediate-mass stars. We find that 0.51-0.73M{sun} white dwarfs, which evolved from 1.7-3.0M{sun} ZAMS progenitors, have a mean rotation period of 35hr with a standard deviation of 28hr, with notable exceptions for higher-mass white dwarfs.
1362. QPQ VI. HI absorption of z~2 quasars
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.
1363. QSO properties from SDSS-DR7
ID:
ivo://CDS.VizieR/J/ApJS/194/45
Title:
QSO properties from SDSS-DR7
Short Name:
J/ApJS/194/45
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a compilation of properties of the 105783 quasars in the Sloan Digital Sky Survey Data Release 7 (DR7) quasar catalog (Cat. VII/260). In this product, we compile continuum and emission line measurements around the H{alpha}, H{beta}, MgII, and CIV regions, as well as other quantities such as radio properties, and flags indicating broad absorption line quasars, disk emitters, etc. We also compile virial black hole mass estimates based on various calibrations. For the fiducial virial mass estimates we use the Vestergaard & Peterson (VP06; 2006ApJ...641..689V) calibrations for H{beta} and CIV, and our own calibration for MgII which matches the VP06 H{beta} masses on average. We describe the construction of this catalog and discuss its limitations.
1364. QSOs at z~6 spectral cubes
ID:
ivo://CDS.VizieR/J/A+A/631/A78
Title:
QSOs at z~6 spectral cubes
Short Name:
J/A+A/631/A78
Date:
21 Oct 2021
Publisher:
CDS
Description:
Outflows in quasars during the early epochs of galaxy evolution are an important part of the feedback mechanisms potentially affecting the evolution of the host galaxy. However, systematic observations of outflows are only now becoming possible with the advent of sensitive mm telescopes. In this study we use spectral stacking methods to search for faint high velocity outflow signal in a sample of [CII] detected, z~6 quasars. We search for broad emission line signatures from high-velocity outflows for a sample of 26 z~6 quasars observed with ALMA, with a detection of the [CII] line. The observed emission lines of the sources are dominated by the host galaxy, and outflow emission is not detected for the individual sources. We use a spectral line stacking analysis developed for interferometric data to search for outflow emission. We stack both extracted spectra and the full spectral cubes. We also investigate the possibility that only a sub-set of our sample contributes to the stacked outflow emission. We find only a tentative detection of a broad emission line component in the stacked spectra. When taking a region of about 2 arcsec around the source central position of the stacked cubes, the stacked line shows an excess emission due to a broad component of 1.1-1.5 sigma, but the significance drops to 0.4-0.7 sigma when stacking the extracted spectra from a smaller region. The broad component can be characterised by a line width of full width half max FWHM > 700 km/s. Furthermore, we find a sub-sample of 12 sources the stack of which maximises the broad component emission. The stack of this sub-sample shows an excess emission due to a broad component of 1.2-2.5 sigma. The stacked line of these sources has a broad component of FWHM>775km/s. Deeper ALMA observations are necessary to confirm the presence of a broad component in the individual spectra.
1365. QSOs Lyman alpha emission line spectra
ID:
ivo://CDS.VizieR/J/MNRAS/400/1493
Title:
QSOs Lyman alpha emission line spectra
Short Name:
J/MNRAS/400/1493
Date:
21 Oct 2021
Publisher:
CDS
Description:
Arguably the best hope of understanding the tail end of the re-ionization of the intergalactic medium (IGM) at redshift z>6 is through the detection and characterization of the Gunn-Peterson damping wing absorption of the IGM in bright quasar spectra. However, the use of quasar spectra to measure the IGM damping wing requires a model of the quasar's intrinsic Lyman{alpha} emission line. Here we quantify the uncertainties in the intrinsic line shapes, and how those uncertainties affect the determination of the IGM neutral fraction. We have assembled a catalogue of high-resolution Hubble Space Telescope spectra of the emission lines of unobscured low-redshift quasars, and have characterized the variance in the shapes of their lines. We then add simulated absorption from the high-redshift IGM to these quasar spectra in order to determine the corresponding uncertainties in re-ionization constraints using current and future samples of z>6 quasar spectra. We find that, if the redshift of the Lyman{alpha} emission line is presumed to coincide with the systemic redshift determined from metal lines, the inferred IGM neutral fraction is systematically biased to low values due to a systematic blueshift of the Lyman{alpha} line relative to the metal lines.
1366. Quasar absorption-line systems
ID:
ivo://CDS.VizieR/J/AJ/112/62
Title:
Quasar absorption-line systems
Short Name:
J/AJ/112/62
Date:
21 Oct 2021
Publisher:
CDS
Description:
A survey of quasar absorbers was conducted using the Infrared Astronomical Satellite (IRAS) database. Quasars with known intervening absorption-line systems and broad absorption line (BAL) QSOs were selected primarily from Junkkarinen et al. (1991ApJS...77..203J). Of the 570 quasars with IRAS data, 52 showed 3{sigma} or better detections in at least one band in SCANPI analysis. The origin of the IRAS flux could be from the absorption-line systems, other galaxies, or the quasar itself. The spectral energy distributions for quasars detected in the absorption-line sample and BAL QSOs were found to be redder than those of two control samples which suggests that some of the IRAS flux may arise in dust associated with the intervening galaxies. IRAS SUPERSCANPI processing was carried out for 77 quasars with known MgII absorption at Zabs<1 to investigate the ensemble far-infrared properties of these objects. SUPERSCANPI processing evaluates the median flux for many different positions on the sky, resulting in an improvement in the effective sensitivity. A control sample consisting of objects with no MgII absorption known at Zabs<1 but with the same distribution of absolute V-magnitude, Zem and radio-loud fraction for the background quasars was also processed. The MgII sample was detected at 3{sigma} or better in all four IRAS bands with a significantly larger flux than the control sample at 60{mu}m and 100{mu}m. If this far-infrared emission is from the absorber galaxies, then the far-infrared luminosity of the composite MgII absorber was found to be comparable to that of a starbursting galaxy, although such a high star-formation rate is inconsistent with the optical and near-infrared colors of low-redshift MgII systems. Four of the quasars with individual IRAS detections have intervening galaxies identified with the MgII absorption-lines. The spectral energy distributions of these galaxies imply far-infrared luminosities in excess of what Arp 220 would give at their redshifts. While all the external evidence suggests that the detection of far-infrared emission from the absorber sample may not be connected to the presence of the MgII absorber, we discuss future observations which may help explain our results.
1367. Quasar black hole masses
ID:
ivo://CDS.VizieR/J/ApJ/669/791
Title:
Quasar black hole masses
Short Name:
J/ApJ/669/791
Date:
21 Oct 2021
Publisher:
CDS
Description:
We investigate the time-dependent variations of ultraviolet (UV) black hole mass estimates of quasars in the Sloan Digital Sky Survey (SDSS). From SDSS spectra of 615 high-redshift (1.69<z<4.75) quasars with spectra from two epochs, we estimate black hole masses using a single-epoch technique, which employs an additional, automated night-sky line removal and relies on UV continuum luminosity and CIV {lambda}1549 emission-line dispersion. Mass estimates show variations between epochs at about the 30% level for the sample as a whole. We determine that for our full sample, measurement error in the line dispersion likely plays a larger role than the inherent variability in terms of contributing to variations in mass estimates between epochs. However, we use the variations in quasars with r-band spectral signal-to-noise ratio greater than 15 to estimate that the contribution to these variations from inherent variability is roughly 20%. We conclude that these differences in black hole mass estimates between epochs indicate that variability does not make a large contribution to the current factor of 2 scatter between mass estimates derived from low- and high-ionization emission lines.
1368. Quasars in ESO/SERC field 927
ID:
ivo://CDS.VizieR/J/MNRAS/266/317
Title:
Quasars in ESO/SERC field 927
Short Name:
J/MNRAS/266/317
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the spectroscopic observations of 56 quasars that were discovered by AQD (Automated Quasar Detection) in a field of ~25.3deg2, centred at (1950) RA l0h40m00s, Dec. 05deg00'00". These observations, with the CTIO 4-m telescope, led to the discovery by Clowes & Campusano of a large group of quasars with size ~100-200h^-1^Mpc at z~1.3. Quasars of particular interest are noted, including one that is a BAL quasar with z~1.78.
1369. Quasars with strong nitrogen emission lines
ID:
ivo://CDS.VizieR/J/ApJ/679/962
Title:
Quasars with strong nitrogen emission lines
Short Name:
J/ApJ/679/962
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on 293 quasars with strong NIV] {lambda}1486 or NIII] {lambda}1750 emission lines (rest-frame equivalent width >3{AA}) at 1.7<z<4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release (Cat. VII/252). These nitrogen-rich (N-rich) objects comprise ~1.1% of the SDSS quasars. The comparison between the N-rich quasars and other quasars shows that the two quasar subsets share many common properties. We also confirm previous results that N-rich quasars have much stronger Ly{alpha} and NV {lambda}1240 emission lines. Strong nitrogen emission in all ionization states indicates high overall nitrogen abundances in these objects. We find evidence that the nitrogen abundance is closely related to quasar radio properties.
1370. QUEST2 BRI photometry of Taurus-Auriga PMS
ID:
ivo://CDS.VizieR/J/AJ/132/2665
Title:
QUEST2 BRI photometry of Taurus-Auriga PMS
Short Name:
J/AJ/132/2665
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a drift-scan survey covering a ~5{deg}x5{deg} region toward the southern portion of the Taurus-Auriga molecular cloud. Data taken in the B,R,I filters with the Quest-2 camera on the Palomar 48 inch (1.2m) Samuel Oschin Telescope were combined with Two Micron All Sky Survey near-infrared photometry to select candidate young stars. Follow-up optical spectroscopy of 190 candidates led to the identification of 42 new low-mass pre-main-sequence stars with spectral types M4-M8, of which approximately half exhibit surface gravity signatures similar to known Taurus stars, while the other half exhibit surface gravity signatures similar to members of the somewhat older Upper Scorpius, TW Hya, and Pic associations.