1. The Allen Telescope Array Twenty-centimeter Survey—a 690 deg2, 12 epoch radio data set. I. Catalog and long-duration transient statistics
- Author
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Amber Bauermeister, Rob Ackermann, J. B. Lugten, Dan Werthimer, Ken Smolek, John Ross, Tom Kilsdonk, Chat Hull, Oren Milgrome, Tom Pierson, John Dreher, Douglas Thornton, Karen Randall, Artyom Vitouchkine, Niklas Wadefalk, Jane Jordan, Ed Fields, Steve Croft, Leo Blitz, Melvyn Wright, Casey J. Law, Tamara T. Helfer, Joeri van Leeuwen, Don Backer, Matt Dexter, Chris Cork, Douglas C.-J. Bock, Matt Fleming, Geoffrey C. Bower, Shannon Atkinson, Garrett K. Keating, Susanne Jorgensen, Jill Tarter, John S. Welch, Colby Gutierrez-Kraybill, Calvin Cheng, Lynn Urry, Seth Shostak, M. M. Davis, David Whysong, Greg Engargiola, Tucker Bradford, James R. Forster, Peter K. G. Williams, William C. Barott, Peter L. McMahon, Dave DeBoer, Peter Backus, G. R. Harp, Andrew Siemion, Dave MacMahon, and High Energy Astrophys. & Astropart. Phys (API, FNWI)
- Subjects
NRAO VLA Sky Survey ,Physics ,010504 meteorology & atmospheric sciences ,Dynamic range ,Epoch (astronomy) ,Flux ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Square degree ,Allen Telescope Array ,Space and Planetary Science ,0103 physical sciences ,Calibration ,010303 astronomy & astrophysics ,Beam (structure) ,0105 earth and related environmental sciences - Abstract
We present the Allen Telescope Array Twenty-centimeter Survey (ATATS), a multi-epoch (12 visits), 690 deg(2) radio 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 rms noise sigma = 3.94 mJy beam(-1) and dynamic range 180, with a circular beam of 150 '' FWHM. It contains 4408 sources to a limiting sensitivity of 5 sigma = 20 mJy beam(-1). 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 similar to 20 ''. 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 of 0.004 deg(-2) on the transient rate for such sources. These results suggest that the greater than or similar to 1 Jy transients reported by Matsumara et al. may not be true transients, but rather variable sources at their flux density threshold.
- Published
- 2010
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