This table contains the source catalog from the Allen Telescope Array
Twenty-centimeter Survey (ATATS), a multi-epoch (12 visits), 690 deg2
image and catalog at 1.4 GHz. The survey is designed to detect rare, very
bright transients as well as to verify the capabilities of the ATA to form
large mosaics. The combined image using data from all 12 ATATS epochs has an
rms noise sigma = 3.94 mJy beam-1
and a dynamic range of 180, with a
circular beam of 150 arcseconds FWHM. It contains 4408 sources to a limiting
sensitivity of 5 sigma = 20 mJy beam-1
. The authors compare the catalog
generated from this 12-epoch combined image to the NRAO VLA Sky Survey
(NVSS), a legacy survey at the same frequency, and find that they can measure
source positions to better than ~ 20 arcseconds. For sources above the ATATS
completeness limit, the median flux density is 97% of the median value for
matched NVSS sources, indicative of an accurate overall flux calibration. The
authors examine the effects of source confusion due to the effects of
differing resolution between the ATATS and NVSS on their ability to compare
flux densities. They detect no transients at flux densities greater than 40
mJy in comparison with NVSS and place a 2 sigma upper limit of 0.004 deg-2
on the transient rate for such sources. These results suggest that the >~ 1
Jy transients reported by Matsumara et al. (2009, AJ, 138, 787) may not be
true transients, but rather variable sources at their flux density threshold.
The Allen Telescope Array Twenty-centimeter Survey - A 690 Square Degree, 12
Epoch Radio Data Set. I. Catalog and Long-duration Transient Statistics
Croft, S. et al.
<Astrophys. J. 719, 45 (2010)>
This table was created by the HEASARC in September 2010 based on
the electronic version of Table 2 from the reference paper which was
obtained from the ApJ web site.
The radio source designation, using the 'ATATS' prefix (for Allen
Telescope Array Twenty-cm Survey) and the J2000.0 equatorial source
coordinates truncated to 1 second of time in RA and 1 arcsecond in Dec, as
recommended by the Dictionary Of Nomenclature of Celestial Objects.
The Right Ascension of the radio source in the selected equinox. This
was given in J2000.0 equatorial coordinates to a precision of 0.1 seconds of
time in the original table.
The Declination of the radio source in the selected equinox. This was
given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in
the original table.
The Galactic Longitude of the radio source.
The Galactic Latitude of the radio source.
The flux density of the radio source at 1.4 GHz as measured in
the ATATS, in mJy.
The rms of the local background in the ATATS map, in mJy.
The major axis of the restoring beam, in arcseconds.
The minor axis of the restoring beam, in arcseconds.
The position angle of the major axis of the restoring beam.
The number of NVSS source matches within 75 arcseconds
of the ATATS source position.
The sum of the integrated flux densities of the NVSS
sources within 75 arcseconds of the ATATS source position.
Questions regarding the ATATS database table can be addressed to the
HEASARC User Hotline
Page Author: Browse Software Development Team
Tuesday, 21-Sep-2010 14:47:03 EDT