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arXiv · 1006.2003

The Allen Telescope Array Twenty-centimeter Survey - A 690-Square-Degree, 12-Epoch Radio Dataset - I: Catalog and Long-Duration Transient Statistics

Steve Croft·Geoffrey C. Bower·Rob Ackermann·Shannon Atkinson·Don Backer·Peter Backus·William C. Barott·Amber Bauermeister·Leo Blitz·Douglas Bock·Tucker Bradford·Calvin Cheng·Chris Cork·Mike Davis·Dave DeBoer·Matt Dexter·John Dreher·Greg Engargiola·Ed Fields·Matt Fleming·James R. Forster·Colby Gutierrez-Kraybill·Gerry Harp·Tamara Helfer·Chat Hull·Jane Jordan·Susanne Jorgensen·Garrett Keating·Tom Kilsdonk·Casey Law·Joeri van Leeuwen·John Lugten·Dave MacMahon·Peter McMahon·Oren Milgrome·Tom Pierson·Karen Randall·John Ross·Seth Shostak·Andrew Siemion·Ken Smolek·Jill Tarter·Douglas Thornton·Lynn Urry·Artyom Vitouchkine·Niklas Wadefalk·Jack Welch·Dan Werthimer·David Whysong·Peter K. G. Williams·Melvyn Wright
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Abstract

We present the Allen Telescope Array Twenty-centimeter Survey (ATATS), a multi-epoch (12 visits), 690 square degree radio image and catalog at 1.4GHz. 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 RMS noise sigma = 3.94mJy / beam and dynamic range 180, with a circular beam of 150 arcsec FWHM. It contains 4408 sources to a limiting sensitivity of S = 20 mJy / beam. We 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 we can measure source positions to better than ~20 arcsec. 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. We examine the effects of source confusion due to the effects of differing resolution between ATATS and NVSS on our ability to compare flux densities. We detect no transients at flux densities greater than 40 mJy in comparison with NVSS, and place a 2-sigma upper limit on the transient rate for such sources of 0.004 per square degree. These results suggest that the > 1 Jy transients reported by Matsumura et al. (2009) may not be true transients, but rather variable sources at their flux density threshold.

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Steve Croft, Geoffrey C. Bower, Rob Ackermann, Shannon Atkinson, Don Backer, Peter Backus, William C. Barott, Amber Bauermeister, Leo Blitz, Douglas Bock, Tucker Bradford, Calvin Cheng, Chris Cork, Mike Davis, Dave DeBoer, Matt Dexter, John Dreher, Greg Engargiola, Ed Fields, Matt Fleming, James R. Forster, Colby Gutierrez-Kraybill, Gerry Harp, Tamara Helfer, Chat Hull, Jane Jordan, Susanne Jorgensen, Garrett Keating, Tom Kilsdonk, Casey Law, Joeri van Leeuwen, John Lugten, Dave MacMahon, Peter McMahon, Oren Milgrome, Tom Pierson, Karen Randall, John Ross, Seth Shostak, Andrew Siemion, Ken Smolek, Jill Tarter, Douglas Thornton, Lynn Urry, Artyom Vitouchkine, Niklas Wadefalk, Jack Welch, Dan Werthimer, David Whysong, Peter K. G. Williams, Melvyn Wright. 2010-06-10. The Allen Telescope Array Twenty-centimeter Survey - A 690-Square-Degree, 12-Epoch Radio Dataset - I: Catalog and Long-Duration Transient Statistics. https://doi.org/10.1088/0004-637x/719/1/45

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