J/ApJS/79/77 J/ApJS/79/77 Bell Lab. H I Survey - High Velocity Clouds A A Stark C F Gammie R W Wilson J Bally R A Linke Astrophys. J. Suppl. 79 77 1992 1992ApJS...79...77S H I data Interstellar medium Radio sources Surveys The sky north of declination -40 deg. was observed in the 21 cm line of atomic hydrogen with the FWHM = 2 deg. beam of the 20 foot horn reflector at AT&T Bell Laboratories, Crawford Hill. The survey covers a velocity range of 654 km/s centered on the Galactic standard of rest, with 5.3 km/s wide filters. This survey is distinguished by its sensitivity to low surface brightness features (antenna temperature about 50 mK) and relative freedom from sidelobe contamination. The high-velocity cloud list was extracted and cataloged automatically from the survey data.

Observations were made as drift scans along even declinations between -40 deg. and +90 deg. at the epoch (1981) of the observations. The horn antenna has a FWHM beam size of 2 deg. at 21 cm. The average rms noise of spectra taken at all declinations is 0.017 K in 5.2 km/s wide channels, although in some cases naseline problems make the survey unreliable at this level. The clouds cataloged were selected to be those near for which the velocities, when projected on the galactic plane at each possible distance, differed from the circular rotation velocities by more than 40 km/sec. The boundaries of the clouds were determined by either a decrease in emission to near the baseline emission or a steep drop in antenna temperature.

num [1,1313] Running number --- pkRAdeg Right Ascension (1950) of peak emission deg pkDEdeg Declination (1950) of peak emission deg pkGLON Galactic longitude of peak emission deg pkGLAT Galactic latitude of peak emission deg maxGLON Maximum galactic longitude of cloud deg minGLON Minimum galactic longitude of cloud deg maxGLAT Maximum galactic latitude of cloud deg minGLAT Minimum galactic latitude of cloud deg maxvel Maximum velocity of cloud km/sec minvel Minimum velocity of cloud km/sec flux Total flux K.km/sec antemp Peak antenna temperature K o_cl Number of points cloud detected --- N.G. Roman NASA/NSSDC/ADC 1994Aug10 J_ApJS_79_77.xml