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- ID:
- ivo://vo-plasma.oeaw.ac.at/vexmag_epn20/vexmag_epn20/epn_core
- Title:
- Venus-Express Magnetometer Data
- Date:
- 12 Feb 2019 13:16:30
- Publisher:
- IWF-OeAW
- Description:
- Venus Magnetic Field in VSO Coordinates
- ID:
- ivo://CDS.VizieR/J/A+A/606/A53
- Title:
- Venus mesosphere ALMA observations
- Short Name:
- J/A+A/606/A53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Water vapor and sulfur compounds are key species in the photochemistry of Venus mesosphere. These species, together with mesospheric temperatures, exhibit drastic temporal variations, both on short timescales (diurnal and day-to-day) as well on long timescales, far from being understood. We targeted CO, SO, H_2_O and SO_2_ transitions in the submillimeter range using the Atacama Large Millimeter Array (ALMA) to study their spatial and temporal variations. Four sets of observations were acquired on different dates in November 2011 during the first ALMA Early Science observation Cycle 0. Venus angular diameter was about 11" with an illumination factor of 92%, so that mostly the day side of the planet was mapped. Assuming a nominal CO abundance profile, we retrieved vertical temperature profiles over the entire disk as a function of latitude and local time. Temperature profiles were later used to retrieve SO, SO_2_, and H_2_O. We used H_2_O as a tracer for water assuming a D/H enrichment of 200 times the terrestrial value. We derived 3-D maps of mesospheric temperatures in the altitude range 70-105km. SO, SO_2_, and H_2_O are characterized by a negligible abundance below ~85km followed by an increase with altitude in the upper mesosphere. Disk-averaged SO abundances present a maximum mixing ratio of 15.0+/-3.1ppb on November 26 followed the next day by a minimum value of 9.9+/-1.2ppb. Due to a very low S/N, SO_2_ could only be derived from the disk-averaged spectrum on the first day of observation revealing an abundance of 16.5+/-4.6ppb. We found a SO_2_/SO ratio of 1.5+/-0.4. Global maps of SO reveal strong variations both with latitude and local time and from day to day with abundance ranging from <1 to 15ppb. H_2_O disk-averages retrievals reveal a steady decrease from November 14 to 27, with the abundance varying from 3.6+/-0.6ppm on the first day to 2.9+/-0.7ppm on the last day. H_2_O maps reveal a slightly higher abundance on the evening side compared to the morning side and a strong depletion between the first and the second day of observation.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A82
- Title:
- Venus photometric flux and los velocities
- Short Name:
- J/A+A/627/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measuring Venus' atmospheric circulation at different altitudes is important for understanding its complex dynamics, in particular the mechanisms driving the super-rotation. Observationally, Doppler imaging spectroscopy is in principle be the most reliable way to measure wind speeds of planetary atmospheres because it directly provides the projected speed of atmospheric particles. However, high-resolution imaging-spectroscopy is challenging, especially in the visible domain, and most of the knowledge about atmospheric dynamics has been obtained with cloud-tracking technique. The objective of the present work is to measure the global properties of Venus' atmospheric dynamics at the altitude of the uppermost clouds, which is probed by reflected solar lines in the visible domain. Our results are based on high-resolution spectroscopic observations with the long slit spectrometer of the solar telescope THEMIS. We present the first instantaneous "radial-velocity snapshot" of any planet of the solar system in the visible domain, i.e., a complete RV map of the planet obtained by stacking data on less than 10% of its rotation period. From this, we measure the properties of the zonal and meridional winds, which we unambiguously detect. We identify a wind circulation pattern that significantly differs from previous knowledge about Venus. The zonal wind displays a "hot spot" structure, featuring about 200m/s at sunrise and 70m/s at noon in the equatorial region. Regarding meridional winds, we detect an equator-to-pole meridional flow peaking at 45m/s at mid latitudes, i.e., which is about twice as large as what was reported so far.
- 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%.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/4400
- Title:
- Veritas family members Yarkovsky drift rates
- Short Name:
- J/MNRAS/469/4400
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The age of a young asteroid family can be determined by tracking the orbits of family members backward in time and showing that they converge at some time in the past. Here we consider the Veritas family. We find that the membership of the Veritas family increased enormously since the last detailed analysis of the family. Using backward integration, we confirm the convergence of nodal longitudes {Omega}, and, for the first time, also obtain a simultaneous convergence of pericenter longitudes {varpi}. The Veritas family is found to be 8.23^+0.37^_-0.31_Myr old. To obtain a tight convergence of {Omega} and {varpi}, as expected from low ejection speeds of fragments, the Yarkovsky effect needs to be included in the modeling of the past orbital histories of Veritas family members. Using this method, we compute the Yarkovsky semi-major axis drift rates, d_a_/dt, for 274 member asteroids. The distribution of d_a_/dt values is consistent with a population of C-type objects with low densities and low thermal conductivities. The accuracy of individual d_a_/dt measurements is limited by the effect of close encounters of member asteroids to (1) Ceres and other massive asteroids, which cannot be evaluated with confidence.
- 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.
22628. VERITAS Source Catalog
- ID:
- ivo://nasa.heasarc/verimaster
- Title:
- VERITAS Source Catalog
- Short Name:
- VERIMASTER
- Date:
- 21 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'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 .
- ID:
- ivo://nasa.heasarc/veroncat
- Title:
- VeronCatalogofQuasars&AGN,13thEdition
- Short Name:
- Veron
- Date:
- 21 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<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 .
- 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.
