- ID:
- ivo://CDS.VizieR/J/ApJ/753/125
- Title:
- Near-IR spectroscopy follow-up of 60 SDSS-DR7 QSOs
- Short Name:
- J/ApJ/753/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Single-epoch virial black hole (BH) mass estimators utilizing broad emission lines have been routinely applied to high-redshift quasars to estimate their BH masses. Depending on the redshift, different line estimators (H{alpha}, H{beta}, MgII{lambda}2798, CIV{lambda}1549) are often used with optical/near-infrared spectroscopy. Here, we use a homogeneous sample of 60 intermediate-redshift (z~1.5-2.2) Sloan Digital Sky Survey quasars with optical and near-infrared spectra covering CIV through H{alpha} to investigate the consistency between different single-epoch virial BH mass estimators.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/V/144
- Title:
- Near-IR spectroscopy of low-mass binaries and brown dwarfs
- Short Name:
- V/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass of a star at formation determines its subsequent evolution and demise. Low-mass stars are the most common products of star formation and their long main-sequence lifetimes cause them to accumulate over time. Star formation also produces many substellar-mass objects known as brown dwarfs, which emerge from their natal molecular clouds and continually cool as they age, pervading the Milky Way. Low-mass stars and brown dwarfs exhibit a wide range of physical characteristics and their abundance make them ideal subjects for testing formation and evolution models. I have examined a pair of pre-main sequence spectroscopic binaries and used radial velocity variations to determine orbital solutions and mass ratios. Additionally, I have employed synthetic spectra to estimate their effective temperatures and place them on theoretical Hertzsprung-Russell diagrams. From this analysis I discuss the formation and evolution of young binary systems and place bounds on absolute masses and radii. I have also studied the late-type T dwarfs revealed by the Wide-field Infrared Survey Explorer (WISE). This includes the exemplar T8 subdwarf Wolf 1130C, which has the lowest inferred metallicity in the literature and spectroscopic traits consistent with old age. Comparison to synthetic spectra implies that the dispersion in near-infrared colors of late-type T dwarfs is a result of age and/or thin sul de clouds. With the updated census of the L, T, and Y dwarfs we can now study specific brown dwarf subpopulations. Finally, I present a number of future studies that would develop our understanding of the physical qualities of T dwarf color outliers and disentangle the tracers of age and atmospheric properties. The thesis is available at: http://www.astro.ucla.edu/~gmace/thesis.html
- ID:
- ivo://CDS.VizieR/III/196
- Title:
- Near-IR stellar spectra from 1.428 to 2.5 um
- Short Name:
- III/196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This library is an EXTENDED VERSION of the library published by A.Lancon and B.Rocca-Volmerange in 1992. The catalog contains near-IR spectra of 84 stars, obtained with the Fourier Transform Spectrograph at the Canada-France-Hawaii Telescope on Mauna Kea, Hawaii. The spectra cover the H and K atmospheric windows, i.e. wavelengths from 1.43 to 2.5 microns, with a typical resolving power of 500. The spectra have all been reduced again in 1996. The general procedure was as described in the original article, except that the intrinsic energy distributions of the stars used as references were assumed to be well represented by the models of Kurucz, 1993. Making extensive use of the Simbad data base, we have searched the literature on each of these stars, looking for effective temperature and extinction determinations. The new reduction improves the reliability of the continua, and reduces possible systematic differences between observing runs. The files contain the reduced spectra in FITS format, with fluxes in arbitrary units of energy per unit frequency (normalised to approximately 1 in the K band) and frequencies in cm^-1^, the natural units of Fourier Transform spectroscopy.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/90
- Title:
- [NeII] emission line observations from SgrA West
- Short Name:
- J/ApJ/755/90
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new observations of the [NeII] emission from the ionized gas in Sgr A West with improved resolution and sensitivity. About half of the emission comes from gas with kinematics indicating it is orbiting in a plane tipped about 25{deg} from the Galactic plane. This plane is consistent with that derived previously for the circumnuclear molecular disk and the northern arm and western arc ionized features. However, unlike most previous studies, we conclude that the ionized gas is not moving along the ionized features, but on more nearly circular paths. The observed speeds are close to, but probably somewhat less than expected for orbital motions in the potential of the central black hole and stars and have a small inward component. The spatial distribution of the emission is well fitted by a spiral pattern. We discuss possible physical explanations for the spatial distribution and kinematics of the ionized gas, and conclude that both may be best explained by a one-armed spiral density wave, which also accounts for both the observed low velocities and the inward velocity component. We suggest that a density wave may result from the precession of elliptical orbits in the potential of the black hole and stellar mass distribution.
645. NEOWISE 2-Band Post-Cryo Single Exposure (L1b) Known Solar System Object Possible Association List
- ID:
- ivo://irsa.ipac/WISE/Catalog/2-Band/SSOPAL
- Title:
- NEOWISE 2-Band Post-Cryo Single Exposure (L1b) Known Solar System Object Possible Association List
- Short Name:
- WISE 2-Band SSO
- Date:
- 01 Oct 2018 20:27:16
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The NEOWISE Post-Cryo Data Release products were generated using data taken during the mission's Post-Cryo survey phase. This phase covers the time following the exhaustion of solid hydrogen in the WISE payload inner cryogen tank, when the detectors and optics gradually warmed until they reached a stable equilibrium temperature near 73.5 K. During this time, WISE's W1 and W2 detectors continued to acquire high quality imaging data with sensitivities close to that during the mission's cryogenic survey phases. The W3 and W4 detectors were fully saturated by the thermal emission from the warming telescope. WISE scanned approximately 70% of the sky during the Post-Cryo survey phase continuing with the same strategy that was used during the full cryogenic survey. The Known Solar System Object Possible Associations List is a compendium of asteroids and comets, with orbits known at the time of WISE second-pass data processing, that were predicted to be within the field-of-view at the time of individual WISE exposures. Individual objects were observed multiple times, so may have multiple entries in the list. When the predicted position of a solar system object is in proximity to a detection in the WISE single-exposures, the WISE source position and brightness information are also provided.
- ID:
- ivo://irsa.ipac/WISE/Catalog/2-Band/SingleExpSourceTbl
- Title:
- NEOWISE 2-Band Post-Cryo Single Exposure (L1b) Source Table
- Short Name:
- WISE 2-Band ST
- Date:
- 01 Oct 2018 20:27:16
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The NEOWISE Post-Cryo Single-exposure Source Database contains 7,337,642,955 measurements of positions and brightness information, uncertainties, time of observation and assorted quality flags made on the individual WISE 7.7s (W1 and W2) Single-exposure images. Because WISE scanned every point on the sky multiple times, the Single-exposure Database contains multiple, independent measurements of objects on the sky. Entries in the Single-exposure Source Database include detections of real astrophysical objects, as well as spurious detections of low SNR noise excursions, transient events such as hot pixels, charged particle strikes and satellite streaks, and image artifacts light from bright sources including the moon. Many of the unreliable detections are flagged in the Single-exposure Database, but they have not been filtered out as they were for the All-Sky Release Source Catalog. Therefore, the Database must be used with caution. Users are strongly encouraged to read the Cautionary Notes before using the Database.
- ID:
- ivo://irsa.ipac/WISE/Catalog/NEOWISE-R/SSOPAL
- Title:
- NEOWISE-R Known Solar System Object Possible Association List
- Short Name:
- NEOWISE-R SSOPAL
- Date:
- 01 Oct 2018 20:27:16
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Near-Earth Object Wide-field Infrared Survey Explorer Reactivation Mission (NEOWISE; Mainzer et al. 2014, ApJ, 792, 30) is a NASA Planetary Science Division space-based survey to detect, track and characterize asteroids and comets, and to learn more about the population of near-Earth objects that could pose an impact hazard to the Earth. NEOWISE systematically images the sky at 3.4 and 4.6 μm, obtaining multiple independent observations on each location that enable detection of previously known and new solar system small bodies by virtue of the their motion. Because it is an infrared survey, NEOWISE detects asteroid thermal emission and is equally sensitive to high and low albedo objects. The Known Solar-System Object Possible Associations List is a compendium of asteroids, comets, planets or planetary satellites, with orbits known at the time of NEOWISE data processing, that were predicted to be within the field-of-view at the time of individual NEOWISE Single-exposures. Individual objects were observed multiple times, so may have multiple entries in the list. When the predicted position of a solar system object is in proximity to a detection in the NEOWISE Single-exposures, the NEOWISE detection position and brightness information are also provided.
- ID:
- ivo://irsa.ipac/WISE/Catalog/NEOWISE-R/Frame_Metadata
- Title:
- NEOWISE-R Single Exposure (L1b) Frame Metadata Table
- Short Name:
- NEOWISE-R Meta
- Date:
- 01 Oct 2018 20:27:16
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Near-Earth Object Wide-field Infrared Survey Explorer Reactivation Mission (NEOWISE; Mainzer et al. 2014, ApJ, 792, 30) is a NASA Planetary Science Division space-based survey to detect, track and characterize asteroids and comets, and to learn more about the population of near-Earth objects that could pose an impact hazard to the Earth. NEOWISE systematically images the sky at 3.4 and 4.6 μm, obtaining multiple independent observations on each location that enable detection of previously known and new solar system small bodies by virtue of the their motion. Because it is an infrared survey, NEOWISE detects asteroid thermal emission and is equally sensitive to high and low albedo objects. The following table contains brief descriptions of all metadata information that is relevant to the processing of Single-exposure (level 1) images and the extraction of sources from the corresponding Single-exposure images. The table contains the unique scan ID and frame number for specific each single-exposure image and the reconstructed right ascension and declination of the image center. Much of the information in this table is processing-specific, and may not be of interest to general users (e.g. flags indicating whether frames have been processed or not, and the date and time for starting of the pipeline etc). The metadata table also contains some characterization and derived statistics of the Single-exposure image frames, basic parameters used for photometry and derived statistics for extracted sources and artifacts. For example, it contains the number of sources with profile-fit photometry Signal-to-Noise (SNR) greater than 3, and the total number of real sources affected by artifacts such as latent images and electronic ghosts.
- ID:
- ivo://irsa.ipac/WISE/Catalog/NEOWISE-R/Source_Table
- Title:
- NEOWISE-R Single Exposure (L1b) Source Table
- Short Name:
- NEOWISE-R ST
- Date:
- 01 Oct 2018 20:27:16
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- The Near-Earth Object Wide-field Infrared Survey Explorer Reactivation Mission (NEOWISE; Mainzer et al. 2014, ApJ, 792, 30) is a NASA Planetary Science Division space-based survey to detect, track and characterize asteroids and comets, and to learn more about the population of near-Earth objects that could pose an impact hazard to the Earth. NEOWISE systematically images the sky at 3.4 and 4.6 μm, obtaining multiple independent observations on each location that enable detection of previously known and new solar system small bodies by virtue of the their motion. Because it is an infrared survey, NEOWISE detects asteroid thermal emission and is equally sensitive to high and low albedo objects. The Single-exposure Source Database is a compendium of position and flux information for source detections made on the individual NEOWISE 7.7s W1 and W2 Single-exposure images. Because NEOWISE scanned the same region of the sky multiple times, the Single-exposure Database contains multiple, independent measurements of objects. Positions, magnitudes in the two NEOWISE bands, astrometric and photometric uncertainties, flags indicating measurement quality, the time of observations and associations with the AllWISE Source Catalog and 2MASS Point Source Catalog are presented for entries in the Database.
- ID:
- ivo://CDS.VizieR/J/A+A/645/A95
- Title:
- NEP raster ROSAT X-ray/Optical catalog
- Short Name:
- J/A+A/645/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The North-Ecliptic Pole is an important region for extragalactic surveys. Deep/wide contiguous surveys are being performed by several space observatories. We analyse all ROSAT pointed and survey observations within 40deg^2^ around the NEP, restricting the field-of-view to the inner 30' radius. We obtain an X-ray catalogue of 805 sources with 0.5-2keV fluxes >2.9*10^-15^erg/cm^2^/s, a factor of three deeper than the ROSAT All-Sky Survey in this field. The sensitivity and angular resolution of our data are comparable to the eROSITA All-Sky Survey expectations. The 50% position error radius of the sample of X-ray sources is ~10". We use HEROES optical and near-infrared imaging photometry from Subaru and CFHT telescopes together with literature catalogues and a new deep and wide Spitzer survey in the field to identify X-ray sources and calculate photometric redshifts for the candidate counterparts. In particular we utilize mid-IR colours to identify AGN X-ray counterparts. Despite relatively large error circles and faint counterparts, confusion and systematic errors, we obtain a rather reliable catalogue of 766 optical counterparts, redshifts and optical classifications. We find a new population of luminous absorbed X-ray AGN at large redshifts, not recognized in previous X-ray surveys, but identified in our work due to the unique combination of survey solid angle, X-ray sensitivity and multiwavelength photometry. We also use the WISE and Spitzer photometry to identify a sample of 185 AGN selected purely through mid-IR colours, most of which are not detected by ROSAT. Their redshifts and upper limits to X-ray luminosity and X-ray-to-optical flux ratios are even higher than for the new class of X-ray selected luminous type 2 AGN (AGN2); they are probably a natural extension of this sample. This unique dataset is important as a reference sample for future deep surveys in the NEP region, in particular for eROSITA and also for Euclid and SPHEREX. We predict that most of the absorbed distant AGN should be readily picked up by eROSITA, but they require sensitive mid-IR imaging to be recognized as optical counterparts.
