A study of the H i and optical properties of Low Surface Brightness galaxies: spirals, dwarfs, and irregulars

Abstract

We present a study of the HI and optical properties of nearby (z 0.1) Low Surface Brightness galaxies (LSBGs). We started with a literature sample of ∼900 LSBGs and divided them into three morphological classes: spirals, irregulars and dwarfs. Of these, we could use ∼490 LSBGs to study their HI and stellar masses, colours and colour magnitude diagrams, and local environment, compare them with normal, High Surface Brightness (HSB) galaxies and determine the differences between the three morphological classes. We found that LSB and HSB galaxies span a similar range in HI and stellar masses, and have a similar M HI /M --M relationship. Among the LSBGs, as expected, the spirals have the highest average HI and stellar masses, both of about 10 9.8 M . The LSGBs' (g-r) integrated colour is nearly constant as function of HI mass for all classes. In the colour magnitude diagram, the spirals are spread over the red and blue regions whereas the irregulars and dwarfs are confined to the blue region. The spirals also exhibit a steeper slope in the M HI /M -M plane. Within their local environment we confirmed that LSBGs are more isolated than HSB galaxies, and LSB spirals more isolated than irregulars and dwarfs. Kolmogorov-Smirnov statistical tests on the HI mass, stellar mass and number of neighbours indicates that the spirals are a statistically different population from the dwarfs and irregulars. This suggests that the spirals may have different formation and HI evolution than the dwarfs and irregulars.

Fundamental Properties of the Dark and the Luminous Matter from the Low Surface Brightness Discs

“…LSBs are not rare objects; they likely comprise 50% of the general galaxy population (e.g., [181,[208][209][210][211][212]) with obvious cosmological implications ( [181,205]). However, the LSBs detection is challenging, due to their surface brightness that is much lower than that of their HSB counterparts and more difficult to detect against the sky [194,213]; observational capability and selection effects inevitably lead to a bias which may jeopardise the understanding of their evolution.…”

“…The LSB disc galaxies show different morphologies (see Figures 9 and 10, [197,212]) from irregulars to spirals. They include both dwarfs and giant galaxies; the latter are sometimes composed of a HSB disc embedded in a larger LSB disc extended out to 100 kpc, as in Malin 1 [199,214,215] (see Figure 10).…”

Hidden in plain sight: UVIT and MUSE discovery of a large, diffuse star-forming galaxy

“…The common unifying factor for all LSBGs and UDGs is that they have diffuse stellar disks, that is, their disks appear to have low stellar surface densities (Sales et al 2020), which can be connected to low star formation rates (Rong et al 2020). Although LSBGs are historically considered to be gas-rich (Honey et al 2018), UDGs may or may not contain gas (Leisman et al 2017;Chowdhury 2019).…”

Hidden in Plain Sight: UVIT and MUSE Discovery of a Large, Diffuse Star-Forming Galaxy

“…their disks appear to have low stellar surface densities (Sales et al 2020), which can be connected to jyoti [at] iiap.res.in low star formation rates (Rong et al 2020). Although LSBGs are historically considered to be gas-rich (Honey et al 2018), UDGs may or may not contain gas (Leisman et al 2017;Chowdhury 2019).…”