An $\rm Hα$ Imaging Survey of the Low Surface Brightness Galaxies Selected from the Spring Sky Region of the 40% ALFALFA HI Survey

Abstract

We present a narrow $\rm Hα$-band imaging survey of 357 low surface brightness galaxies (LSBGs) that are selected from the spring sky region of the 40% Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) HI Survey. All the $\rm Hα$ images are obtained from the 2.16 m telescope, operated by Xinglong Observatory of the National Astronomical Observatories, Chinese Academy of Sciences. We provide the $\rm Hα$ fluxes and derive the global star formation rates (SFRs) of LSBGs after the Galactic extinction, internal extinction, and [NII] contamination correction. Comparing to normal star-forming galaxies, LSBGs have a similar distribution in the HI surface density ($\rm Σ_{HI}$), but their SFRs and star formation surface density ($\rm Σ_{SFR}$) are much lower. Our results show that the gas-rich LSBGs selected from the ALFALFA survey obviously deviate from the Kennicutt-Schmidt law, in the relation between the star formation surface density ($\rm Σ_{SFR}$) and the gas surface density ($\rm Σ_{gas}$). However, they follow the extended Schmidt law well when taking the stellar mass of the galaxy into consideration.

17 pages, 11 figures