A deep wide survey of faint low surface brightness galaxies in the direction of the Coma cluster of galaxies

Abstract

Aims. We report on a search for faint (R total magnitude fainter than 21) and low surface brightness galaxies (R central surface brightness fainter than ~ 24) (fLSBs) in a 0.72 x 0.82 deg^2 area centered on the Coma cluster. Methods. We analyzed deep B and R band CCD imaging obtained using the CFH12K camera at CFHT and found 735 fLSBs. The total B magnitudes, at the Coma cluster redshift, range from -13 to -9 with B central surface brightness as faint as 27 mag arcsec^(-2). Results. Using empty field comparisons, we show that most of these fLSBs are probably inside the Coma cluster. We present the results of comparing the projected fLSB distributions with the distributions of normal galaxies and with known X-ray over densities. We also investigate their projected distribution relative to their location in the color magnitude relation. Colors of fLSBs vary between B-R ~ 8 and ~ 1.4 for 2/3 of the sample and this part is consistent with the known CMR red-sequence for bright (R ≤ 18) ellipticals in Coma. Conclusions. These fLSBs are likely to have followed the same evolution as giant ellipticals, which is consistent with a simple feedback/collapse formation and a passive evolution. These fLSBs are mainly clustered around NGC 4889. We found two other distinct fLSB populations. These populations have respectively redder and bluer colors compared to the giant elliptical red-sequence and possibly formed from stripped faint ellipticals and material stripped from spiral in-falling galaxies.