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Object code assessments

• CODE 1: Refers to sources of S/N and general qualities that make it a reliable detection. By ``general qualities'' we mean that, in addition to an approximate S/N threshold of 6.5, the signal should exhibit a good match between the two independent polarizations and a spatial extent consistent with expectations given the telescope beam characteristics. Thus, some candidate detections with S/N>6.5 have been excluded on grounds of polarization mismatch, spectral vicinity to rfi features or peculiar spatial properties. Likewise, some features of S/N<6.5 are included as reliable detections, due to optimal overall characteristics of the feature. The S/N threshold for acceptance of a reliable detection candidate is thus soft. In a preliminary fashion, we estimate that detection candidates with S/N<6.5 are reliable.
• CODE 2: Refers to sources of low S/N (< 6.5), which would ordinarily not be considered reliable detections by the criteria set for code 1. However, those HI candidate sources are matched with optical counterparts with known optical redshifts which match those measured in the HI line. These candidate sources, albeit ``detected'' by our signal finding algorithm, are accepted as likely counterparts only because of the existence of previously available, corroborating optical spectroscopy. We refer to these sources as ``priors''. We include them in our catalog because they are very likely to be real.
• CODE 9: Refers to objects assumed to be HVCs - no distance estimate is made.

Acknowledgements

The National Astronomy and Ionosphere Center

The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation.

The National Virtual Observatory

This research has made use of data obtained from or software provided by the US National Virtual Observatory, which is sponsored by the National Science Foundation.

Sloan Digital Sky Survey

Funding for the Sloan Digital Sky Survey (SDSS) and SDSS-II has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, the U.S. Department of Energy, the National Aeronautics and Space Administration, the Japanese Monbukagakusho, and the Max Planck Society, and the Higher Education Funding Council for England. The SDSS Web site is http://www.sdss.org/.

The SDSS is managed by the Astrophysical Research Consortium (ARC) for the Participating Institutions. The Participating Institutions are the American Museum of Natural History, Astrophysical Institute Potsdam, University of Basel, University of Cambridge, Case Western Reserve University, The University of Chicago, Drexel University, Fermilab, the Institute for Advanced Study, the Japan Participation Group, The Johns Hopkins University, the Joint Institute for Nuclear Astrophysics, the Kavli Institute for Particle Astrophysics and Cosmology, the Korean Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos National Laboratory, the Max-Planck-Institute for Astronomy (MPIA), the Max-Planck-Institute for Astrophysics (MPA), New Mexico State University, Ohio State University, University of Pittsburgh, University of Portsmouth, Princeton University, the United States Naval Observatory, and the University of Washington.

DSS Information

The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions. The National Geographic Society - Palomar Observatory Sky Atlas (POSS-I) was made by the California Institute of Technology with grants from the National Geographic Society. The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation. The Oschin Schmidt Telescope is operated by the California Institute of Technology and Palomar Observatory. The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together known as the SERC-J), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken with the UK Schmidt.