- ID:
- ivo://CDS.VizieR/J/AJ/126/1996
- Title:
- 100 brightest X-ray stars within 50pc of the Sun
- Short Name:
- J/AJ/126/1996
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Based on the Hipparcos and Tycho-2 astrometric catalogs and the ROSAT surveys, a sample of ~100 stars most luminous in X-rays within or around a distance of 50 pc is culled. The smallest X-ray luminosity in the sample is LX=9.8x10^29^erg/s; the strongest source in the solar neighborhood is II Peg, a RS CVn star, at LX=175.8x10^29^erg/s. With respect to the origin of X-ray emission, the sample is divided into partly overlapping classes of pre-main-sequence, post-T Tauri, and very young ZAMS objects (type XY), RS CVn-type binary stars (type RS), other active short-period binaries, including binary BY Dra-type objects (type XO), apparently single or long-period binary active evolved stars (type XG), contact binaries of WU UMa kind (type WU), apparently single or long-period binary variable stars of BY Dra kind (type BY), and objects of unknown nature (type X?). Chromospherically active, short-period binaries (RS and XO) make up 40% of the brightest X-ray emitters, followed by young stars (XY) at 30% and unknown sources (X?) at 15%.
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Search Results
- ID:
- ivo://nasa.heasarc/at20gbspol
- Title:
- Bright Extra-Galactic AT20G Sources Polarizations Catalog
- Short Name:
- AT20GBSPOL
- Date:
- 14 Feb 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- This table contains polarization data for 180 extragalactic sources extracted from the Australia Telescope 20-GHz (AT20G) survey catalog and observed with the Australia Telescope Compact Array (ATCA) during a dedicated, high sensitivity run (sigma<sub>P</sub> ~ 1 mJy). For the sake of completeness, the authors extracted the polarization information for seven extended sources from the 9-yr Wilkinson Microwave Anisotropy Probe co-added maps at 23 GHz. The full sample of 187 sources constitutes a ~ 99% complete sample of extragalactic sources brighter than S<sub>20GHz</sub> = 500 mJy at the selection epoch with Declination below -30<sup>o</sup>. The sample has a 91.4% detection rate in polarization at ~ 20 GHz (94% if considering the sub-sample of point-like sources). The authors have measurements also at 4.8 and 8.6 GHz within ~1 month of the 20-GHz observations for 172 sources so as to reconstruct the spectral properties of the sample in total intensity and in polarization: 143 of them have a polarization detection at all three frequencies. The authors find that there is no statistically significant evidence of a relationship either between the fraction of polarization and frequency or between the fraction of polarization and the total intensity flux density. This indicates that Faraday depolarization is not very important above 4.8 GHz and that the magnetic field is not substantially more ordered in the regions dominating the emission at higher frequencies (up to 20 GHz). The authors estimate the distribution of the polarization fraction and the polarized flux density source counts at ~20 GHz. The selection of the sample was based on the list of confirmed AT20G sources available at the epoch of these observations (2006 October). The authors selected all objects with flux density S<sub>20GHz</sub> > 500 mJy and Declination below -30<sup>o</sup>, excluding the Galactic plane region (|b| <= 1.5o^) and the Large Magellanic Cloud (LMC) region (inside a circle of 5.5<sup>o</sup> radius centered at RA =05:23:34.7 and Dec=-69:45:22 in J2000.0 coordinates). This resulted in a complete sample of 189 sources. The observations were taken on October 1, 2006 using the most compact hybrid configuration of ATCA, H75, excluding the data from the farthest antenna. The longest baseline of this configuration is 75 m, and its T-shape ensures adequate Fourier coverage for snapshots taken on a relatively small range of hour angles and at high elevation. In a number of cases, indicated by source_flags values of 's', 'f' or 'w', the highest frequency data is not at 18 GHz, but at 20 or 23 GHz. This table was created by the HEASARC in January 2015 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/436/2915">CDS Catalog J/MNRAS/436/2915</a> file table2.dat. This is a service provided by NASA HEASARC .
- ID:
- ivo://CDS.VizieR/J/MNRAS/216/173
- Title:
- Bright extragalactic radio sources at 2.7 GHz
- Short Name:
- J/MNRAS/216/173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The brightest extragalactic radio sources at 2.7 GHz are catalogued. The complete sample comprises 233 sources found in the major centimeter wavelength surveys carried out at ANRAO/Parkes, NNRAO/Greenbank, and MPIfR/Bonn: the sample covers 9.81 sr and has limits S(27) = 2.0 Jy and |b| > 10{deg}. A critical reanalysis of the data shows that 227 (97 percent) have optical identifications and 171 (73 percent) have measured redshifts. The implications of the catalogue statistics for the luminosity functions of different radio-source populations are considered.
- ID:
- ivo://CDS.VizieR/VIII/5
- Title:
- Bright Extragalactic Radio Sources (1Jy)
- Short Name:
- VIII/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog is a compilation of 518 extragalactic radio sources with flux densities greater than 1 Jy at 5 GHz. It contains sources from the NRAO-MPI 5-GHz Strong Source Surveys and from re-observation at 5 GHz of sources found in the Parkes 2.7-GHz surveys. All sources were found in 9.811 sr covered by the two surveys. This is essentially the whole sky, excluding the galactic plane (latitudes less than 10 degrees) and the Magellanic Clouds. The catalog includes radio flux densities, radio positions, object classes, visual magnitudes, redshifts, and spectral indices.
- ID:
- ivo://CDS.VizieR/J/ApJS/149/365
- Title:
- Bright filamentary structures in the ISM
- Short Name:
- J/ApJS/149/365
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a listing of prominent filamentary structures in the interstellar cirrus, selected with an eye toward current and planned far-infrared and submillimeter polarimetry facilities. The filaments were identified on the 100{mu}m plates of the IRAS Sky Survey Atlas (ISSA, Wheelock et al. 1994, IRAS Sky Survey Atlas: Explanatory Supplement (JPL Publ. 94-11; Pasadena: JPL)), using a computer vision algorithm that is unbiased with respect to source intensity. Our catalog is two-tiered: the selection criteria in the Galactic plane are based on the sensitivity limits of airborne polarimeters such as the proposed HALE instrument for SOFIA, and away from the plane the limits are dictated by the sensitivities of balloon-borne cosmic microwave background experiments, such as BOOMERanG and MAXIMA. Infrared detector technology is currently at the point where detecting the polarization of the interstellar cirrus is feasible, and we hope this catalog will assist any experimenter undertaking this task.
- ID:
- ivo://CDS.VizieR/J/ApJ/902/127
- Title:
- Bright Gaia white dwarfs with unWISE photometry
- Short Name:
- J/ApJ/902/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of excess infrared radiation around white dwarfs provide important constraints on the evolution of planetary systems and low-mass companions beyond the main-sequence stage. In this paper series, we focus on identifying and characterizing bright white dwarfs with an infrared excess. Here, we present 188 infrared excess candidates from Gaia and unWISE, 147 of which are new discoveries. Further characterization of this sample can significantly increase the current list of white dwarf debris disks and white dwarfs with low-mass companions.
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/2018
- Title:
- 6 bright Galactic Cepheids data
- Short Name:
- J/MNRAS/430/2018
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of photometric and spectroscopic data of six bright Galactic Cepheids: GH Carinae, V419 Centauri, V898 Centauri, AD Puppis, AY Sagittarii and ST Velorum. Based on new radial velocity data (in some cases supplemented with earlier data available in the literature), these Cepheids have been found to be members in spectroscopic binary systems. V898 Cen turned out to have one of the largest orbital radial velocity amplitude (>40km/s) among the known binary Cepheids. The data are insufficient to determine the orbital periods nor other orbital elements for these new spectroscopic binaries. These discoveries corroborate the statement on the high frequency of occurrence of binaries among the classical Cepheids, a fact to be taken into account when calibrating the period-luminosity relationship for Cepheids. We have also compiled all available photometric data that revealed that the pulsation period of AD Pup, the longest period Cepheid in this sample, is continuously increasing with {Delta}P=0.004567d/century, likely to be caused by stellar evolution. The wave-like pattern superimposed on the parabolic O-C graph of AD Pup may well be caused by the light-time effect in the binary system. ST Vel also pulsates with a continuously increasing period. The other four Cepheids are characterized with stable pulsation periods in the last half century.
- ID:
- ivo://CDS.VizieR/J/AJ/138/251
- Title:
- Bright Galactic stars with 24um excesses
- Short Name:
- J/AJ/138/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optically bright Galactic stars (V<~13mag) having f_nu_(24um)>1mJy are identified in Spitzer mid-infrared surveys within 8.2deg^2^ for the Bootes field of the NOAO Deep Wide-Field Survey and within 5.5deg^2^ for the First Look Survey (FLS). One hundred and twenty-eight stars are identified in Bootes and 140 in the FLS, and their photometry is given. (K-[24]) colors are determined using K magnitudes from the Two Micron All Sky Survey for all stars in order to search for excess 24um luminosity compared to that arising from the stellar photosphere.
- ID:
- ivo://CDS.VizieR/J/A+A/339/34
- Title:
- Bright galaxies from the WENSS minisurvey
- Short Name:
- J/A+A/339/34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for bright galaxies associated with radio sources from the Westerbork Northern Sky Survey (WENSS) minisurvey has been carried out. A galaxy counterpart was found for 402 of almost 10,000 radio sources. Of these a radio and optically complete sample, with a flux density limit at 325MHz of 30mJy and a limiting red magnitude of 16, can be constructed, which contains 119 galaxies. This paper is the first step of a more general study, in which we aim to derive a bright galaxy sample from the entire WENSS survey (which is now available in the public domain) and thus to construct practically definitive local radio luminosity functions of elliptical and spiral galaxies. We briefly describe the WENSS minisurvey, and the steps that are needed for the optical identification of its radio sources. Due to the large numbers of sources involved (over 200,000) completely automated procedures are obviously needed and we discuss these in some detail. It is shown that with modern utilities projects as described here have become quite feasible. Some results (e.g. a preliminary determination of the local radio luminosity function) are presented.
- ID:
- ivo://CDS.VizieR/J/A+A/487/453
- Title:
- Bright galaxies in 5 medium redshift clusters. I.
- Short Name:
- J/A+A/487/453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from five clusters of galaxies within the redshift range 0.15<=z<=0.25, imaged with the Nordic Optical Telescope (NOT) in the central ~1Mpc^2^ in very good seeing conditions, we have performed an exhaustive inspection of their bright galaxy population. That range of redshift, where only a small amount of data with the required resolution and quality is available, is particularly important for the understanding of the formation and evolution of clusters of galaxies. We have inspected the color-magnitude relation (CMR) for those clusters and measured the blue fraction of galaxies in their cores to check for evidence of evolution as found in other works. Visual classification of the galaxy morphology has been performed and the morphology-radius relation examined.
