THE ARECIBO L-BAND FEED ARRAY ZONE OF AVOIDANCE SURVEY. I. PRECURSOR OBSERVATIONS THROUGH THE INNER AND OUTER GALAXY
- Institute for Astrophysics, University of New Mexico, MSC07 4220, 800 Yale Blvd., NE, Albuquerque, NM 87131 (United States)
- Anglo-Australian Observatory, P.O. Box 296, Epping, NSW 1710 (Australia)
- National Astronomy and Ionosphere Center-Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612 (United States)
- National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)
- Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, D-85741 Garching (Germany)
- Department of Astrophysics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602 (Japan)
- Australia Telescope National Facility, CSIRO, P.O. Box 76, Epping, NSW 2121 (Australia)
- Department of Physics and Astronomy, George Mason University, Fairfax, VA 22030 (United States)
- Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)
- School of Physics, University of Western Australia, Crawley, WA 6009 (Australia)
- GEPI, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 place Jules Janssen, 92190 Meudon (France)
The Arecibo L-band Feed Array (ALFA) is being used to conduct a low-Galactic latitude survey, to map the distribution of galaxies and large-scale structures behind the Milky Way through detection of galaxies' neutral hydrogen (H I) 21 cm emission. This Zone of Avoidance (ZOA) survey finds new H I galaxies which lie hidden behind the Milky Way, and also provides redshifts for partially obscured galaxies known at other wavelengths. Before the commencement of the full survey, two low-latitude precursor regions were observed, totaling 138 deg{sup 2}, with 72 H I galaxies detected. Detections through the inner Galaxy generally have no cataloged counterparts in any other waveband, due to the heavy extinction and stellar confusion. Detections through the outer Galaxy are more likely to have Two Micron All Sky Survey counterparts. We present the results of these precursor observations, including a catalog of the detected galaxies, with their H I parameters. The survey sensitivity is well described by a flux- and linewidth-dependent signal-to-noise ratio of 6.5. ALFA ZOA galaxies, which also have H I measurements in the literature, show good agreement between our measurements and previous work. The inner Galaxy precursor region was chosen to overlap the H I Parkes Zone of Avoidance Survey, so ALFA performance could be quickly assessed. The outer Galaxy precursor region lies north of the Parkes sky. Low-latitude large-scale structure in this region is revealed, including an overdensity of galaxies near l = 183{sup 0} and between 5000-6000 km s{sup -1} in the ZOA. The full ALFA ZOA survey will be conducted in two phases: a shallow survey using the observing techniques of the precursor observations, and also a deep phase with much longer integration time, with thousands of galaxies predicted for the final catalog.
- OSTI ID:
- 21443103
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 139, Issue 6; Other Information: DOI: 10.1088/0004-6256/139/6/2130; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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