The SPECFIND V3.0 catalog of radio continuum cross-identifications and spectra Reaching lower frequencies. (2021)
Keywords :
catalogs - radio continuum general - astronomical data bases: miscellaneous
Abstract:Many radio continuum catalogs with different sensitivity limits and spatial resolutions are published via the VizieR database. Because of the diversity of spatial resolution, the cross-identification of individual sources is complex. By assuming a power-law spectrum, the SPECFIND tool is able to handle radio surveys at different frequencies from different instruments and different resolutions. Since the former version of the SPECFIND catalog was released ten years ago, hundreds of new radio continuum catalogs have been published. We upgraded the SPECFIND tool to reach a wider frequency range, especially the lower-frequency radio regime, as well as to have
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We present a new version of SPECFIND. The SPECFIND tool was
successfully upgraded from 115 catalogs in version 2.0 to version 3.0
with a final number of 204 processed catalogs. 89 new catalogs were
ingested and two catalogs were updated. The final number of resulting
spectra was increased more than a factor of three from 107500 in
version 2.0 to 340000 in version 3.0. The number of objects with
cross-identified sources was more than doubled from 600000 in version
2.0 to 1.6 million in version 3.0.
The main result is presented in table "spectra" with every radio
continuum source having one entry row. The different objects/spectra
are named by different sequence numbers (column "Seq"). All radio
continuum sources with the same sequence number belong to the same
object/spectrum. In the second column, the name of the source is given
followed by the number of sources within the spectrum ("N"). The
columns "a" and "b" are the spectral index and the abscissa of the
spectral fit, respectively. The sixth column contains the frequency of
the catalog, followed by the flux density, its error and the position
of the source (Right Ascension and Declination). The column "SED" is a
link to the spectral fit, i.e. the spectrum containing this source.
The next column "Aladin" shows an Aladin Lite6 view of the source. The
last column gives the beam size of the observation.
The "beam" table contains all 204 tables from the VizieR catalogs
which were used in SPECFIND V3.0.
The "waste" table has the same general structure as "spectra", but
contains measurements which were cross-identified by position but did
not match the power-law spectrum. These points are added to the VizieR
SED plot.
The spectral break sources are provided in two different tables. The
first table contains all 5515 spectral break sources including the 210
concave sources with turnover frequencies around 1.4GHz. The second
table lists the 19691 spectral break sources including the 900 concave
sources with turnover frequencies around 325MHz. The structure of the
tables is similar to the spectra table. The first column gives the
running number "Seq". The sources belonging to the same spectrum have
the same sequence number. The second column provides the source name;
the third column the type (spectral break (sb), concave (conc),
GPS/MPS (gps/mps), GGPS/GMPS (ggps/gmps)), followed by the spectral
slope and the abscissa associated with the source. In the next column,
the mean spectral slope of the part of the spectrum (lower or higher
frequency part) is given. Then the frequency, the flux density and its
error are listed. Lastly, the position (Right Ascension and
Declination) and the beam/resolution are specified.
Yelena Stein, yelena.stein(at)astro.unistra.fr
