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16831. VERA 22GHz Fringe Search Survey
ID:
ivo://CDS.VizieR/J/AJ/133/2487
Title:
VERA 22GHz Fringe Search Survey
Short Name:
J/AJ/133/2487
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper presents results of a survey search for bright compact radio sources at 22GHz with the VERA radio interferometer. Each source from a list of 2494 objects was observed in one scan for 2 minutes. The purpose of this survey was to find compact extragalactic sources bright enough at 22GHz to be useful as phase calibrators. Observed sources were either (1) within 6{deg} of the Galactic plane, or (2) within 11{deg} of the Galactic center, or (3) within 2{deg} of known water masers. Among the observed sources, 549 were detected, including 180 extragalactic objects that were not previously observed with the very long baseline interferometry technique. Estimates of the correlated flux densities of the detected sources are presented. It was found that the probability of detecting a 200mJy source with 120s of integration time is 60%.
16832. VERITAS gamma-ray TeV LCs of 6 blazars
ID:
ivo://CDS.VizieR/J/ApJ/833/117
Title:
VERITAS gamma-ray TeV LCs of 6 blazars
Short Name:
J/ApJ/833/117
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a targeted search for blazar flux-correlated high-energy ({epsilon}_{nu}_>~1TeV) neutrinos from six bright northern blazars, using the public database of northern hemisphere neutrinos detected during "IC40" 40-string operations of the IceCube neutrino observatory (2008 April to 2009 May). Our six targeted blazars are subjects of long-term monitoring campaigns by the VERITAS TeV {gamma}-ray observatory. We use the publicly available VERITAS light curves to identify periods of excess and flaring emission. These predefined intervals serve as our "active temporal windows" in a search for an excess of neutrinos, relative to Poisson fluctuations of the near-isotropic atmospheric neutrino background, which dominates at these energies. After defining the parameters of an optimized search, we confirm the expected Poisson behavior with Monte Carlo simulations prior to testing for excess neutrinos in the actual data. We make two searches: one for excess neutrinos associated with the bright flares of Mrk 421 that occurred during the IC40 run, and one for excess neutrinos associated with the brightest emission periods of five other blazars (Mrk 501, 1ES 0806+524, 1ES 1218+304, 3C 66A, and W Comae), all significantly fainter than the Mrk 421 flares. We find no significant excess of neutrinos from the preselected blazar directions during the selected temporal windows. We derive 90% confidence upper limits on the number of expected flux-associated neutrinos from each search. These limits are consistent with previous point-source searches and Fermi GeV flux-correlated searches. Our upper limits are sufficiently close to the physically interesting regime that we anticipate that future analyses using already-collected data will either constrain models or yield discovery of the first blazar-associated high-energy neutrinos.
16833. VERITAS Source Catalog
ID:
ivo://nasa.heasarc/verimaster
Title:
VERITAS Source Catalog
Short Name:
VERIMASTER
Date:
28 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is a major ground-based gamma-ray observatory operating at the Fred Lawrence Whipple Observatory (FLWO) in southern Arizona, USA. It is an array of four 12m optical telescopes for gamma-ray astronomy in the GeV - TeV energy range. VERITAS is an imaging air Cerenkov system. Gamma-rays from astrophysical sources create particle showers in the Earth's upper atmosphere that produce Cerenkov photons detected on the ground using the large optical telescopes. These telescopes are deployed such that they have the highest sensitivity in the VHE energy band (50 GeV - 50 TeV), with maximum sensitivity from 100 GeV to 10 TeV. The four telescope array is needed for stereoscopic observations that allow the reconstruction of the particle shower geometry, thus giving precise angular and energy resolution. This very high energy observatory, completed in 2007, effectively complements the Fermi Gamma-ray Space Telescope due to its large collection area as well as its higher energy bound and improved angular resolution. VERITAS started four-telescope operations in 2007 and collects about 1100 hours of good-weather data per year. The VERITAS collaboration has published over 100 journal articles since 2008 reporting on gamma-ray observations of a large variety of objects: Galactic sources like supernova remnants, pulsar wind nebulae, and binary systems; extragalactic sources like star forming galaxies, dwarf-spheroidal galaxies, and highly-variable active galactic nuclei. Additional details are available at the <a href="https://veritas.sao.arizona.edu/">VERITAS website</a>. The catalog lists the sources observed by VERITAS as of April 2022, including cross-matches with other gamma-ray observations and spectral fits. This catalog has associated high-level data products containing data from VERITAS publications. This database table was ingested by the HEASARC in December 2022 and is based upon data files provided by the VERITAS Team. A minor correction to one entry in the catalog was made in April 2024. <p> High-level data products were collected from VERITAS publications. Data and fit results were extracted from the published papers or from internal VERITAS analysis results used to produce the published figures and tables. In many cases, spectral and light curve data were obtained by digitizing published figures. This process was led by Gernot Maier at DESY with contributions from many members of the VERITAS collaboration. The primary archive can be accessed on <a href="https://github.com/VERITAS-Observatory/VERITAS-VTSCat">GitHub</a> or downloaded via Zenodo (doi:10.5281/zenodo.6163391). Translation to formats suitable for the HEASARC was led by Philip Kaaret with assistance by Sameer Patel at the University of Iowa and by the HEASARC Team. This is a service provided by NASA HEASARC .
16834. VeronCatalogofQuasars&AGN,13thEdition
ID:
ivo://nasa.heasarc/veroncat
Title:
VeronCatalogofQuasars&AGN,13thEdition
Short Name:
Veron
Date:
28 Mar 2025
Publisher:
NASA/GSFC HEASARC
Description:
This database table contains the 13th edition of the Catalog of Quasars and Active Galactic Nuclei by Veron-Cetty and Veron, and is an update of the previous versions. As in the previous editions, no information about absorption lines or X-ray properties is given, but absolute magnitides are provided, assuming a Hubble constant H<sub>0</sub> = 71 km/s/Mpc and a deceleration parameter q<sub>0</sub> = 0 (notice the change of cosmology from previous editions in which H<sub>0</sub> was assumed to be 50 km/s/Mpc). The present edition of this catalog contains 133336 quasars, 1374 BL Lac objects and 34231 active galaxies (including 15627 Seyfert 1 galaxies), for a grand total of 168941 objects, significantly more than the number of objects listed in the 12th edition (108080). The 13th edition includes positions and redshifts, as well as photometry (U, B, and V) and 6-cm and 20-cm flux densities, when available. 178 objects once proposed but now rejected as quasars are NOT included in the online version of this catalog: their names and positions are listed in the file <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/258/reject.dat">https://cdsarc.cds.unistra.fr/ftp/cats/VII/258/reject.dat</a>. This HEASARC table also does NOT contain the additional information on gravitationally lensed quasars and quasar pairs listed in Tables 3 and 4 of the published paper: these tables are available in electronic form at the CDS <a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/248/">https://cdsarc.cds.unistra.fr/ftp/cats/VII/248/</a> files table2.dat and table3.dat (sic). The present edition of this catalog contains quasars with measured redshift known prior to July 1st, 2009. This online catalog was created by the HEASARC in April 2010 based on machine-readable tables obtained from the CDS (their catalog VII/258, files qso.dat, bllac.dat, and agn.dat). It was last updated in June 2012 to tweak some class values. This is a service provided by NASA HEASARC .
16835. Vertical distribution of galactic disk stars
ID:
ivo://CDS.VizieR/J/A+A/398/141
Title:
Vertical distribution of galactic disk stars
Short Name:
J/A+A/398/141
Date:
21 Oct 2021
Publisher:
CDS
Description:
Nearly 400 Tycho-2 (Cat. <I/259>) stars have been observed in a 720 square degree field in the direction of the North Galactic Pole with the high resolution echelle spectrograph ELODIE. Absolute magnitudes, effective temperatures, gravities and metallicities have been estimated, as well as distances and 3D velocities. Most of these stars are clump giants and span typical distances from 200pc to 800pc to the galactic mid-plane. This new sample, free of any kinematical and metallicity bias, is used to investigate the vertical distribution of disk stars.
16836. Vertical motions of APOGEE & Gaia red clump stars
ID:
ivo://CDS.VizieR/J/ApJ/878/21
Title:
Vertical motions of APOGEE & Gaia red clump stars
Short Name:
J/ApJ/878/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
It has long been known that the vertical motions of Galactic disk stars increase with stellar age, commonly interpreted as vertical heating through orbit scattering. Here we map the vertical actions of disk stars as a function of age ({tau}<=8Gyr) and across a large range of Galactocentric radii, R_GC_, drawing on APOGEE and Gaia data. We fit J_z_(R_GC,{tau}_) as a combination of the vertical action at birth, J_z,0_, and the subsequent heating {Delta}J_z,1Gyr_(R_GC_), which scales as {tau}^{gamma}(R_GC_)^. The inferred birth temperature, J_z,0_(R_GC_) is 1kpc.km/s for 3kpc<R_GC_<10kpc, consistent with the ISM velocity dispersion, but it rapidly rises outward, to 8kpc.km/s for R_GC_=14kpc, likely reflecting the stars' birth in a warped or flared gas disk. We find the heating rate {Delta}J_z,1Gyr_ to be modest and nearly constant across all radii, 1.6kpc.km/s/Gyr. The stellar age dependence {gamma} gently grows with Galactocentric radius, from {gamma}~1 for R_GC_<~R_{sun}_ to {gamma}~1.3 at R_GC_=14kpc. The observed J_z_-{tau} relation at all radii is considerably steeper ({gamma}>~1) than the time dependence theoretically expected from orbit scattering, J_z_{propto}t^0.5^. We illustrate how this conundrum can be resolved if we also account for the fact that at earlier epochs, the scatterers were more common, and the restoring force from the stellar disk surface mass density was low. Our analysis may reinstate gradual orbital scattering as a plausible and viable mechanism to explain the age-dependent vertical motions of disk stars.
16837. Vertical structure of edge-on galaxies
ID:
ivo://CDS.VizieR/J/A+A/389/795
Title:
Vertical structure of edge-on galaxies
Short Name:
J/A+A/389/795
Date:
21 Oct 2021
Publisher:
CDS
Description:
To analyze the vertical structure of edge-on galaxies, we have used images of a large uniform sample of flat galaxies that have been taken during the 2MASS all-sky survey. The photometric parameters, such as the radial scale length, the vertical scale height, and the deprojected central surface brightness of galactic disks have been obtained. We find a strong correlation between the central surface brightness and the ratio of the vertical scale height to the vertical scale length: the thinner the galaxy, the lower the central surface brightness of its disk. The vertical scale height does not increase systematically with the distance from the galaxy center in the frames of this sample.
16838. Very cold C-rich circumstellar envelopes
ID:
ivo://CDS.VizieR/J/A+A/267/515
Title:
Very cold C-rich circumstellar envelopes
Short Name:
J/A+A/267/515
Date:
21 Oct 2021
Publisher:
CDS
Description:
The paper develops a method for identification of very cold C-rich circumstellar envelopes (CSEs) in IR regions colder than region VII (i.e., larger value of IRAS flux ratio S25/S12), by reviewing the different criteria and by identifying C-rich CSEs in a sample of 228 bright IRAS sources. By using the results of OH surveys and catalogs together with the results of additional HCN/CO millimeter observations performed on critical classes of objects, a C/O classification is proposed for 94 percent of the sources with a good probability. It is shown that the low-resolution spectra by themselves are a reasonable and easy way to identify C-rich late AGB CSEs. For post-AGB object with cold CSEs, HCN and OH observations or visible/near IR spectroscopy are necessary.
16839. Very Low-Luminosity Objects (VeLLOs) from 1.25-850um
ID:
ivo://CDS.VizieR/J/ApJS/225/26
Title:
Very Low-Luminosity Objects (VeLLOs) from 1.25-850um
Short Name:
J/ApJS/225/26
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a search for Very Low-Luminosity Objects (VeLLOs) in the Gould Belt (GB) clouds using infrared and sub-millimeter (sub-mm) data from 1.25 to 850{mu}m and our N_2_H^+^(J=1-0) observations. We modified the criteria by Dunham et al. (2008, J/ApJS/179/249) to select the VeLLOs in the GB clouds, finding 95 VeLLO candidates, 79 of which are newly identified in this study. Out of 95 sources, 44 were detected in both sub-mm continuum and N_2_H^+^ emission and were classified as Group A (the VeLLOs), and 51 sources detected in either sub-mm emission or N_2_H^+^ emission were classified with Group B as candidate VeLLOs. We find that these VeLLOs and the candidates are forming in environments different from those of the likely VeLLOs. Seventy-eight sources are embedded within their molecular clouds, and thus are likely VeLLOs forming in a dense environment. The remaining 17 sources are located in low-level extinction regions (A_V_<1) connected to the clouds, and can be either background sources or candidate substellar objects forming in an isolated mode. The VeLLOs and the candidates are likely more luminous and their envelopes tend to be more massive in denser environments. The VeLLOs and the candidates are more populous in the clouds where more YSOs form, indicating that they form in a manner similar to that of normal YSOs. The bolometric luminosities and temperatures of the VeLLOs are compared to predictions of episodic accretion models, showing that the low luminosities for most VeLLOs can be well explained by their status in the quiescent phases of a cycle of episodic mass accretion.
16840. Very low-mass binaries with Gaia DR2 data
ID:
ivo://CDS.VizieR/J/ApJ/889/176
Title:
Very low-mass binaries with Gaia DR2 data
Short Name:
J/ApJ/889/176
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of WISE 2150-7520AB (W2150AB): a widely separated (~341au) very low-mass L1+T8 co-moving system. The system consists of the previously known L1 primary 2MASS J21501592-7520367 and a newly discovered T8 secondary found at position 21:50:18.99-75:20:54.6 (MJD=57947) using Wide-field Infrared Survey Explorer data via the Backyard Worlds: Planet 9 citizen science project. We present Spitzer ch1 and ch2 photometry (ch1-ch2=1.41+/-0.04mag) of the secondary and Folded-port InfraRed Echellette prism spectra of both components. The sources show no peculiar spectral or photometric signatures, indicating that each component is likely field age. Using all observed data and the Gaia DR2 parallax of 41.3593+/-0.2799mas for W2150A we deduce fundamental parameters of log(L_bol_/L_{sun}_)=-3.69+/-0.01, Teff=2118+/-62K, and an estimated mass=72+/-12M_Jup_ for the L1 and log(L_bol_/L_{sun}_)=-5.64+/-0.02, Teff=719+/-61K, and an estimated mass=34+/-22M_Jup_ for the T8. At a physical separation of ~341au this system has E_bin_=10^41^erg, making it the lowest binding energy system of any pair with M_tot_<0.1M_{sun}_ not associated with a young cluster. It is equivalent in estimated mass ratio, E_bin_, and physical separation to the ~2Myr M7.25+M8.25 binary brown dwarf 2MASS J11011926-7732383AB (2M1101AB) found in the Chameleon star-forming region. W2150AB is the widest companion system yet observed in the field where the primary is an L dwarf or later.

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