Red, Gas Rich Low Surface Brightness Galaxies And Enigmatic Deviations from the Tully-Fisher Relation

Abstract

[Abridged] Using the refurbished 305m Arecibo Gregorian Telescope, we detected 43 low surface brightness (LSB) galaxies from the catalog of O'Neil, Bothun, & Cornell (1997a). The detected galaxies range from 22.0 mag/arcsec^2 < mu_B(0) < 25.0 mag/arcsec^2, with colors ranging from the blue through the first detection of a very red LSB galaxies (B-V = -0.7 to 1.7). The M_HI/L_B of these galaxies ranges from 0.1 Msol/Lsol -- 50 Msol/Lsol, showing this sample to range from very gas poor to possibly the most gas rich galaxies ever detected. One of the more intriguing results of this survey is that the galaxies with the highest M_HI/L_B correspond to some of the reddest (optically) galaxies in the survey, raising the question of why star formation has not continued in these galaxies. Since the average H I column density in these systems is above the threshold for massive star formation, the lack of such may indicate that these galaxies form some kind of ``optical core'' which trace a much more extended distribution of neutral hydrogen. A subset of the detected LSB galaxies have rotational velocities > 200 km s^{-1} and yet are at least an order of magnitude below L* in total luminosity. As such, they represent extreme departure from the standard Tully-Fisher relation. In fact, our sample does not appear to have any significant correlation between the velocity widths and absolute magnitudes, with only 40% of the galaxies falling within the 1 sigma low surface brightness galaxy Tully-Fisher relation.