Near-Infrared Imaging of Barred Halo Dominated Low Surface Brightness Galaxies

TL;DR

This study uses near-infrared imaging to analyze the properties of bars in low surface brightness galaxies, revealing that bars are rare but as strong as in normal galaxies, with uniform stellar populations and no significant color gradients.

Contribution

It provides the first detailed NIR imaging analysis of barred LSB galaxies, showing their bars are similar in strength to those in high surface brightness galaxies despite their rarity.

Findings

Bars are present in about 8.3% of LSB galaxies.

Most bars are brighter and as strong as those in normal galaxies.

Bars show no significant color gradient, indicating uniform stellar populations.

Abstract

We present a near-infrared (NIR) imaging study of barred low surface brightness (LSB) galaxies using the TIFR near-infrared Spectrometer and Imager (TIRSPEC). LSB galaxies are dark matter dominated, late type spirals that have low luminosity stellar disks but large neutral hydrogen (HI) gas disks. Using SDSS images of a very large sample of LSB galaxies derived from the literature, we found that the barred fraction is only 8.3%. We imaged twenty five barred LSB galaxies in the J, H, K$_S$ wavebands and twenty nine in the K$_S$ band. Most of the bars are much brighter than their stellar disks, which appear to be very diffuse. Our image analysis gives deprojected mean bar sizes of $R_{b}/R_{25}$ = 0.40 and ellipticities $e$ $\approx$ 0.45, which are similar to bars in high surface brightness galaxies. Thus, although bars are rare in LSB galaxies, they appear to be just as strong as bars found in normal galaxies. There is no correlation of $R_{b}/R_{25}$ or $e$ with the relative HI or stellar masses of the galaxies. In the (J-K$_S$) color images most of the bars have no significant color gradient which indicates that their stellar population is uniformly distributed and confirms that they have low dust content.