A NEUTRAL HYDROGEN SURVEY OF POLAR-RING GALAXIES .1. GREEN BANK OBSERVATIONS OF THE NORTHERN SAMPLE

We present the results of a neutral hydrogen survey conducted with the Green Bank 140 foot radio telescope of 47 northern objects in the polar-ring galaxy atlas of Whitmore et al. [AJ, 100, 1489 (1990)]. We detected 39 of these above our detection limit of 1.7 Jy km s-1; the average measured flux of 21 Jy km s-1 corresponds to an average neutral hydrogen mass of 5.3 X 10(9) M. for a Hubble constant of H-0=75 km s-1 Mpc-1. For the polar-ring galaxies in our sample that have also been observed with radio arrays, we find that the 21'(FWHM) Green Bank beam often includes much more flux than found by the synthesis instruments for the polar rings alone; some of these galaxies are known to have gas-rich companions. We compare the neutral hydrogen content of the sample to the blue luminosity and IRAS fluxes. The H I-mass-to-blue-light ratios of the confirmed and probable polar rings are around unity in solar units, indicating that polar-ring galaxies (or their environments) are as gas-rich as typical irregular galaxies. For their blue luminosity, the confirmed polar rings are underluminous in the far infrared, as compared with the rest of the sample. They are also FIR underluminous for their H I masses, which suggests that most of the gas in the ring may be in stable orbits, rather than flowing inward to trigger star formation in the central galaxy. The more disordered class of ''related objects,'' which includes a number of obvious mergers, is highly luminous in the far infrared. Detailed notes for each galaxy, including information about companions within the GB 140' beam that may contribute to the total H I line integral and its width, are contained in the Appendix.