Variation in optical and infrared properties of galaxies in relation to their surface brightness

Abstract

Although it is now recognized that low surface brightness galaxies (LSBs) constitute a large fraction of the number density of galaxies, many of their properties are still poorly known. Based on only a few studies, LSBs are often considered to be “dust poor”, that is, with a very low amount of dust. For the first time, we use a large sample of LSBs and high surface brightness galaxies (HSBs) with deep observational data to study the variation of stellar and dust properties as a function of the surface brightness-surface mass density. Our sample consists of 1631 galaxies that were optically selected (with ugrizy-bands) at z < 0.1 from the North Ecliptic Pole (NEP) Wide field. We used the large multiwavelength set of ancillary data in this field ranging from UV to the far-infrared wavelengths. We measured the optical size and the surface brightness of the targets and analyzed their spectral energy distribution using the CIGALE fitting code. Based on the average r-band surface brightness (μ̄e), our sample consists of 1003 LSBs (μ̄e > 23 mag arcsec−2) and 628 HSBs (μ̄e ≤ 23 mag arcsec−2). We found that the specific star formation rate and specific infrared luminosity (total infrared luminosity per stellar mass) remain mostly flat as a function of surface brightness for both LSBs and HSBs that are star forming, but these characteristics decline steeply when the LSBs and HSBs are quiescent galaxies. The majority of LSBs in our sample have negligible dust attenuation (< 0.1 mag), and only about 4% of them show significant attenuation, with a mean V-band attenuation of 0.8 mag. We found that the LSBs with a significant attenuation also have a high r-band mass-to-light ratio (M/Lr > 3 M⊙/L⊙), making them outliers from the linear relation of surface brightness and stellar mass surface density. These outlier LSBs also show similarity to the extreme giant LSBs from the literature, indicating a possibly higher dust attenuation in giant LSBs. This work provides a large catalog of LSBs and HSBs as well as detailed measurements of several optical and infrared physical properties. Our results suggest that the dust content of LSBs is more varied than previously thought, with some of them having significant attenuation that makes them fainter than their intrinsic value. With these results, we will be able to make predictions on the dust content of the population of LSBs and how the presence of dust will affect their observations from current and upcoming surveys like JWST and LSST.