CO Detections of Edge-on Low Surface Brightness Galaxies

Abstract

We have obtained deep CO(1-0) observations of 8 nearby, edge-on, low surface brightness (LSB) spiral galaxies using the NRAO 12-m telescope. We report detections of 3 of our targets at >4 sigma level as well as one marginal (~3 sigma) detection. These are among the first direct detections of molecular gas in late-type, LSB spirals. Using a Galactic CO-to-H2 conversion factor, we derive MH2~1.4-3.5 x 10^{7}Msun and MH2/MHI~0.010-0.055 for the detected sources, with 3-sigma upper limits of MH2<0.7-5.7 x 10^{7}Msun and MH2/MHI<0.006-0.029 for the undetected objects.