Near-infrared imaging of barred halo-dominated low surface brightness galaxies

Abstract

We present a near-infrared (NIR) imaging study of barred low surface brightness (LSB) galaxies using the TIFR<cross-ref type="fn" refid="fn1">1</cross-ref> NIR Spectrometer and Imager. LSB galaxies are dark matter dominated, late-type spirals that have low-luminosity stellar discs but large neutral hydrogen (H <scp>i</scp>) gas discs. Using Sloan Digital Sky Survey images of a very large sample of LSB galaxies derived from the literature, we found that the barred fraction is only 8.3 per cent. We imaged 25 barred LSB galaxies in the <it>J</it>, <it>H</it>, <it>K</it><inf>S</inf> wavebands and 29 in the <it>K</it><inf>S</inf> band. Most of the bars are much brighter than their stellar discs, which appear to be very diffuse. Our image analysis gives deprojected mean bar sizes of <it>R</it><inf>b</inf>/<it>R</it><inf>25</inf> = 0.40 and ellipticities <it>e</it> ≈ 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 <it>R</it><inf>b</inf>/<it>R</it><inf>25</inf> or <it>e</it> with the relative H <scp>i</scp> or stellar masses of the galaxies. In the (<it>J</it> − <it>K</it><inf>S</inf>) colour images most of the bars have no significant colour gradient which indicates that their stellar population is uniformly distributed and confirms that they have low dust content.