M. Beijersbergen | Searcharxiv

arXiv2002

Deprojection of luminosity functions of galaxies in the Coma cluster

We use a simple analytic model to deproject 2-d luminosity functions (LF) of galaxies in the Coma cluster measured by Beijersbergen et al. 2002. We demonstrate that the shapes of the LFs change after deprojection. It is therefore essential to correct LFs for projection effects. The deprojected LFs of the central area have best-fitting Schechter parameters of M^{*}_U=-18.31^{+0.08}_{-0.08} and α_U=-1.27^{+0.018}_{-0.018}, M^{*}_B=-19.79^{+0.14}_{-0.15} and α_B=-1.44^{+0.016}_{-0.016} and M^{*}_r=-21.77^{+0.20}_{-0.28} and α_r=-1.27^{+0.012}_{-0.012}. The corrections are not significant enough to change the previously observed trend of increasing faint end slopes with increasing distance to the cluster center. The weighted U, B, and r band slopes of the deprojected LFs show a slightly weaker steepening with increasing projected cluster radius.

astro-ph↗

arXiv1999

Surface photometry of bulge dominated low surface brightness galaxies

We present results of broad band {BVRI} observations of a sample of galaxies with a low surface brightness (LSB) disk and a bulge. These galaxies are well described as exponential disks and exponential bulges with no preferred value for either scale length or central surface brightness. The median {B} band disk scale length is 12.6 kpc (H_(0) = 75 km s^{-1} Mpc^{-1}) which is much larger than scale lengths of typical (disk dominated) LSB or high surface brightness (HSB) galaxies. Furthermore, the disk and bulge scale lengths are correlated, suggesting a coupling in the formation. Bulge dominated LSB galaxies are observed to be redder than disk dominated LSB galaxies and their bulge-to-disk ratios are increasing towards redder wavelengths. We find colors that are comparable to or bluer than HSB galaxies of the same morphological types. Bulge dominated LSB galaxies are therefore not faded HSB galaxies with no current star formation. We find that bulge dominated LSB galaxies fit in with the general trends defined by the HSB galaxies. The properties of these bulge dominated LSB galaxies show that LSB galaxies do not just come in two varieties. They cover the entire range in optical and morphological properties between late-type disk dominated LSBs and giant Malin-1-like LSBs. LSB galaxies thus also form a LSB Hubble sequence, parallel to the classical HSB one.

astro-ph↗