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Title: The FIRST survey: Faint Images of the Radio Sky at Twenty centimeters

Abstract

The FIRST survey to produce Faint Images of the Radio Sky at Twenty centimeters is now underway using the NRAO Very Large Array. We describe here the scientific motivation for a large-area sky survey at radio frequencies which has a sensitivity and angular resolution comparable to the Palomar Observatory Sky Survey, and we recount the history that led to the current survey project. The technical design of the survey is covered in detail, including a description and justification of the grid pattern chosen, the rationale behind the integration time and angular resolution selected, and a summary of the other considerations which informed our planning for the project. A comprehensive description of the automated data analysis pipeline we have developed is presented. We also report here the results of the first year of FIRST observations. A total of 144 hr of time in 1993 April and May was used for a variety of tests, as well as to cover an initial strip of the survey extending between 07{sup h}15{sup m} and 16{sup h}30{sup m} in a 2{sq_bullet}8 wide declination zone passing through the local zenith (28.2{lt}{delta}{lt}31.0). A total of 2153 individual pointings yielded an image database containing 1039 merged images 46{sq_bullet}5{times}34{sq_bullet}5more » in extent with 1{center_dot}{double_prime}8 pixels and a typical rms of 0.13 mJy. A catalog derived from this 300 deg{sup 2} region contains 28,000 radio sources. We have performed extensive tests on the images and source list in order to establish the photometric and astrometric accuracy of these data products. We find systematic astrometric errors of {lt}0{center_dot}{double_prime}05; individual sources down to the 1 mJy survey flux density threshold have 90{percent} confidence error circles with radii of {lt}1{double_prime}. CLEAN bias introduces a systematic underestimate of point-source flux densities of {approximately}0.25 mJy; the bias is more severe for extended sources. (Abstract Truncated)« less

Authors:
 [1];  [2];  [3]
  1. Department of Physics, University of California, Davis, and Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, Livermore, California 94450 (United States)
  2. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218 (United States)
  3. Department of Astronomy and Columbia Astrophysics Laboratory, 538 West 120th Street, New York, New York 10027 (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
279461
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 450; Journal Issue: 2; Other Information: PBD: Sep 1995
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; COSMIC RADIO SOURCES; FLUX DENSITY; IMAGES; CATALOGS; GHZ RANGE 01-100; MAPS; SENSITIVITY; ASTROMETRY; ASTRONOMICAL SURVEYS; VLA

Citation Formats

Becker, R.H., White, R.L., and Helfand, D.J. The FIRST survey: Faint Images of the Radio Sky at Twenty centimeters. United States: N. p., 1995. Web. doi:10.1086/176166.
Becker, R.H., White, R.L., & Helfand, D.J. The FIRST survey: Faint Images of the Radio Sky at Twenty centimeters. United States. doi:10.1086/176166.
Becker, R.H., White, R.L., and Helfand, D.J. Fri . "The FIRST survey: Faint Images of the Radio Sky at Twenty centimeters". United States. doi:10.1086/176166.
@article{osti_279461,
title = {The FIRST survey: Faint Images of the Radio Sky at Twenty centimeters},
author = {Becker, R.H. and White, R.L. and Helfand, D.J.},
abstractNote = {The FIRST survey to produce Faint Images of the Radio Sky at Twenty centimeters is now underway using the NRAO Very Large Array. We describe here the scientific motivation for a large-area sky survey at radio frequencies which has a sensitivity and angular resolution comparable to the Palomar Observatory Sky Survey, and we recount the history that led to the current survey project. The technical design of the survey is covered in detail, including a description and justification of the grid pattern chosen, the rationale behind the integration time and angular resolution selected, and a summary of the other considerations which informed our planning for the project. A comprehensive description of the automated data analysis pipeline we have developed is presented. We also report here the results of the first year of FIRST observations. A total of 144 hr of time in 1993 April and May was used for a variety of tests, as well as to cover an initial strip of the survey extending between 07{sup h}15{sup m} and 16{sup h}30{sup m} in a 2{sq_bullet}8 wide declination zone passing through the local zenith (28.2{lt}{delta}{lt}31.0). A total of 2153 individual pointings yielded an image database containing 1039 merged images 46{sq_bullet}5{times}34{sq_bullet}5 in extent with 1{center_dot}{double_prime}8 pixels and a typical rms of 0.13 mJy. A catalog derived from this 300 deg{sup 2} region contains 28,000 radio sources. We have performed extensive tests on the images and source list in order to establish the photometric and astrometric accuracy of these data products. We find systematic astrometric errors of {lt}0{center_dot}{double_prime}05; individual sources down to the 1 mJy survey flux density threshold have 90{percent} confidence error circles with radii of {lt}1{double_prime}. CLEAN bias introduces a systematic underestimate of point-source flux densities of {approximately}0.25 mJy; the bias is more severe for extended sources. (Abstract Truncated)},
doi = {10.1086/176166},
journal = {Astrophysical Journal},
number = 2,
volume = 450,
place = {United States},
year = {1995},
month = {9}
}