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2081. 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.
2082. 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.
2083. 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.
2084. Quasar composite made from bright QSOs
ID:
ivo://CDS.VizieR/J/A+A/585/A87
Title:
Quasar composite made from bright QSOs
Short Name:
J/A+A/585/A87
Date:
21 Oct 2021
Publisher:
CDS
Description:
Quasi-stellar object (QSO) spectral templates are important both to QSO physics and for investigations that use QSOs as probes of intervening gas and dust. However, combinations of various QSO samples obtained at different times and with different instruments so as to expand a composite and to cover a wider rest frame wavelength region may create systematic effects, and the contribution from QSO hosts may contaminate the composite. We have constructed a composite spectrum from luminous blue QSOs at 1<z<2.1 selected from the Sloan Digital Sky Survey (SDSS). The observations with X-shooter simultaneously cover ultraviolet (UV) to near-infrared (NIR) light, which ensures that the composite spectrum covers the full rest-frame range from Ly{beta} to 11350{AA} without any significant host contamination. Assuming a power-law continuum for the composite we find a spectral slope of {alpha}{lambda}=1.70+/-0.01, which is steeper than previously found in the literature. We attribute the differences to our broader spectral wavelength coverage, which allows us to effectively avoid fitting any regions that are affected either by strong QSO emissions lines (e.g., Balmer lines and complex [FeII] blends) or by intrinsic host galaxy emission. Finally, we demonstrate the application of the QSO composite spectrum for evaluating the reddening in other QSOs.
2085. 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.
2086. 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.
2087. 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.
2088. Quiet-sun hydrogen Lyman-alpha line profile
ID:
ivo://CDS.VizieR/J/A+A/644/A109
Title:
Quiet-sun hydrogen Lyman-alpha line profile
Short Name:
J/A+A/644/A109
Date:
21 Oct 2021
Publisher:
CDS
Description:
The solar radiation in the Lyman-alpha spectral line of hydrogen plays a significant role in the illumination of chromospheric and coronal structures, such as prominences, spicules, chromospheric fibrils, cores of coronal mass ejections, and solar wind. Moreover, it is important for the investigation of the heliosphere, Earth's ionosphere, and the atmospheres of planets, moons, and comets. We derive a reference quiet-Sun Lyman-alpha spectral profile that is representative of the Lyman-alpha radiation from the solar disk during a minimum of solar activity. This profile can serve as an incident radiation boundary condition for the radiative transfer modelling of chromospheric and coronal structures. Because the solar radiation in the Lyman lines is not constant over time but varies significantly with the solar cycle, we provide a method for the adaptation of the incident radiation Lyman line profiles (Lyman-alpha and higher lines) to a specific date. Moreover, we analyse how the change in the incident radiation influences the synthetic spectra produced by the radiative transfer modelling. We used SOHO/SUMER Lyman-alpha raster scans obtained without the use of the attenuator in various quiet-Sun regions on the solar disk. The observations were performed on three consecutive days (June 24, 25, and 26, 2008) during a period of minimum solar activity. The reference Lyman-alpha profile was obtained as a spatial average over eight available raster scans. To take into account the Lyman-alpha variation with the solar cycle, we used the LISIRD composite Lyman-alpha index. To estimate the influence of the change in the incident radiation in the Lyman lines on the results of radiative transfer models, we used a 2D prominence fine structure model. We present the reference quiet-Sun Lyman-alpha profile and a table of coefficients describing the variation of the Lyman lines with the solar cycle throughout the lifetime of SOHO. The analysis of the influence of the change in the incident radiation shows that the synthetic spectra are strongly affected by the modification of the incident radiation boundary condition. The most pronounced impact is on the central and integrated intensities of the Lyman lines. There, the change in the synthetic spectra can often have the same amplitude as the change in the incident radiation itself. The impact on the specific intensities in the peaks of reversed Lyman-line profiles is smaller but still significant. The hydrogen Halpha line can also be considerably affected, despite the fact that the Halpha radiation from the solar disk does not vary with the solar cycle.
2089. Radial Velocities in HD50526 system with CORALIE
ID:
ivo://CDS.VizieR/J/AJ/162/66
Title:
Radial Velocities in HD50526 system with CORALIE
Short Name:
J/AJ/162/66
Date:
14 Mar 2022 08:24:15
Publisher:
CDS
Description:
We present a photometric and spectroscopic study of HD50526, an ellipsoidal binary member of the group Double Periodic Variable stars. Performing data mining in photometric surveys and conducting new spectroscopic observations with several spectrographs during 2008-2015, we obtained orbital and stellar parameters of the system. The radial velocities were analyzed with the genetic PIKAIA algorithm, whereas Doppler tomography maps for the H{alpha} and H{beta} lines were constructed with the Total Variation Minimization code. An optimized simplex algorithm was used to solve the inverse problem adjusting the light curve with the best stellar parameters for the system. We find an orbital period of 6.701{+/-}0.001d and a long photometric cycle of 191{+/-}2 days. We detected the spectral features of the coldest star and modeled it with a logg=2.79{+/-}0.02dex giant of mass 1.13{+/-}0.02 M{sun} and effective temperature 10500{+/-}125K. In addition, we determine a mass ratio q=0.206{+/-}0.033 and that the hot star is a B-type dwarf of mass 5.48{+/-}0.02M{sun}. The V-band orbital light curve can be modeled including the presence of an accretion disk around the hotter star. This fills the Roche lobe of the hotter star and has a radius 14.74{+/-}0.02R{sun} and the temperature at the outer edge is 9400 K. Two bright spots located in the disk account for the global morphology of the light curve. The Doppler tomography maps of H{alpha} and H{beta} reveal complex structures of mass fluxes in the system.
2090. Radial Velocities of 3 giant stars with planets
ID:
ivo://CDS.VizieR/J/A+A/580/A14
Title:
Radial Velocities of 3 giant stars with planets
Short Name:
J/A+A/580/A14
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the discovery of two giant planets around the intermediate-mass evolved star HIP65891 and HIP107773. The best Keplerian fit to the HIP65891 and HIP107773 radial velocities leads to the following orbital parameters: P=1084.5d; Mpsini=6.0M_Jup_; e=0.13 and P=144.3d; Mpsini=2.0M_Jup_; e=0.09, respectively. In addition, we confirm the planetary nature of the outer object orbiting the giant star HIP67851. The orbital parameters of HIP67851c are: P=2131.8d, Mpsini=6.0M_Jup_, and e=0.17.

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