FUV and NIR size of the HI selected low surface brightness galaxies

Abstract

Abstract How low surface brightness galaxies (LSBGs) form stars and assemble stellar mass is one of the most important questions related to understanding the LSBG population. We select a sample of 381 HI bright LSBGs with both far ultraviolet (FUV) and near infrared (NIR) observations to investigate the star formation rate (SFR) and stellar mass scales, and the growth mode. We measure the FUV and NIR radii of our sample, which represent the star-forming and stellar mass distribution scales respectively. We also compare the FUV and H band radius-stellar mass relation with archival data, to identify the SFR and stellar mass structure difference between the LSBG population and other galaxies. Since galaxy HI mass has a tight correlation with the HI radius, we can also compare the HI and FUV radii to understand the distribution of HI gas and star formation activities. Our results show that most of the HI selected LSBGs have extended star formation structure. The stellar mass distribution of LSBGs may have a similar structure to disk galaxies at the same stellar mass bins, but the star-forming activity of LSBGs happens at a larger radius than the high surface density galaxies, which may help to identify the LSBG sample from the wide-field deep u band image survey. The HI is also distributed at larger radii, implying a steeper (or not) Kennicutt-Schmidt relation for LSBGs.