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16821. Velocity measurements in Segue 1
ID:
ivo://CDS.VizieR/J/ApJ/733/46
Title:
Velocity measurements in Segue 1
Short Name:
J/ApJ/733/46
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a comprehensive Keck/DEIMOS spectroscopic survey of the ultra-faint Milky Way satellite galaxy Segue 1. We have obtained velocity measurements for 98.2% of the stars within 67pc (10', or 2.3 half-light radii) of the center of Segue 1 that have colors and magnitudes consistent with membership, down to a magnitude limit of r=21.7. Based on photometric, kinematic, and metallicity information, we identify 71 stars as probable Segue 1 members, including some as far out as 87pc. After correcting for the influence of binary stars using repeated velocity measurements, we determine a velocity dispersion of 3.7^+1.4^_-1.1_km/s. The mass within the half-light radius is 5.8^+8.2^_-3.1_x10^5^M_{sun}_. The stellar kinematics of Segue 1 require very high mass-to-light ratios unless the system is far from dynamical equilibrium, even if the period distribution of unresolved binary stars is skewed toward implausibly short periods. With a total luminosity less than that of a single bright red giant and a V-band mass-to-light ratio of 3400M_{sun}_/L_{sun}_, Segue 1 is the darkest galaxy currently known.
16822. Velocity of eight RASSCALS galaxy groups
ID:
ivo://CDS.VizieR/J/ApJ/622/187
Title:
Velocity of eight RASSCALS galaxy groups
Short Name:
J/ApJ/622/187
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study the distribution of gas pressure and entropy in eight groups of galaxies belonging to the ROSAT All-Sky Survey/Center for Astrophysics Loose Systems (RASSCALS, Cat. <J/ApJ/534/114>). We use archival and proprietary XMM-Newton observations, supplementing the X-ray data with redshifts derived from the literature; we also list 125 new redshifts measured with the Gemini North telescope.
16823. Velocity precision in the Gaia-ESO Survey
ID:
ivo://CDS.VizieR/J/A+A/580/A75
Title:
Velocity precision in the Gaia-ESO Survey
Short Name:
J/A+A/580/A75
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Gaia-ESO Survey (GES) is a large public spectroscopic survey at the European Southern Observatory Very LargeTelescope. A key aim is to provide precise radial velocities (RVs) and projected equatorial velocities (vsini) for representative samples of Galactic stars, which will complement information obtained by the Gaia astrometry satellite. We present an analysis to empirically quantify the size and distribution of uncertainties in RV and vsini using spectra from repeated exposures of the same stars. We show that the uncertainties vary as simple scaling functions of signal-to-noise ratio (S/N) and vsini, that the uncertainties become larger with increasing photospheric temperature, but that the dependence on stellar gravity, metallicity and age is weak. The underlying uncertainty distributions have extended tails that are better represented by Students t-distributions than by normal distributions. Parametrised results are provided, which enable estimates of the RV precision for almost all GES measurements, and estimates of the vsini precision for stars in young clusters, as a function of S/N, vsini and stellar temperature. The precision of individual high S/N GES RV measurements is 0.22-0.26km/s, dependent on instrumental configuration.
16824. Velocity Vectors of B and A stars
ID:
ivo://CDS.VizieR/V/30
Title:
Velocity Vectors of B and A stars
Short Name:
V/30
Date:
21 Oct 2021
Publisher:
CDS
Description:
A compilation of proper motions, radial velocities, and apparent magnitudes of B and A stars is combined with the absolute magnitudes and colour excesses from the "Catalogue of estimated astrophysical parameters" by Philip and Egret (at. V/14).
16825. 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%.
16826. 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.
16827. VERITAS Source Catalog
ID:
ivo://nasa.heasarc/verimaster
Title:
VERITAS Source Catalog
Short Name:
VERIMASTER
Date:
14 Feb 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&#39;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 &lt;a href="https://veritas.sao.arizona.edu/"&gt;VERITAS website&lt;/a&gt;. 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. &lt;p&gt; 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 &lt;a href="https://github.com/VERITAS-Observatory/VERITAS-VTSCat"&gt;GitHub&lt;/a&gt; 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 .
16828. VeronCatalogofQuasars&AGN,13thEdition
ID:
ivo://nasa.heasarc/veroncat
Title:
VeronCatalogofQuasars&AGN,13thEdition
Short Name:
Veron
Date:
14 Feb 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&lt;sub&gt;0&lt;/sub&gt; = 71 km/s/Mpc and a deceleration parameter q&lt;sub&gt;0&lt;/sub&gt; = 0 (notice the change of cosmology from previous editions in which H&lt;sub&gt;0&lt;/sub&gt; 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 &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/258/reject.dat"&gt;https://cdsarc.cds.unistra.fr/ftp/cats/VII/258/reject.dat&lt;/a&gt;. 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 &lt;a href="https://cdsarc.cds.unistra.fr/ftp/cats/VII/248/"&gt;https://cdsarc.cds.unistra.fr/ftp/cats/VII/248/&lt;/a&gt; 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 .
16829. 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.
16830. 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.

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