Search for Compact Elliptical Galaxies in SDSS DR7

摘要

Compact elliptical (cE) galaxies, a rare morphological type exemplified by M32, which has a very small effective radius, and high central surface brightness. As a result of known cEs being nearby massive neighbours, they are suspected to be the result of tidal truncation driven by interactions with them, although it has also been proposed they are the low-mass end of the normal ellipticals. The small number of known cEs makes their study difficult and we therefore undertook a search for further examples. Moreover, to properly test the stripping theory of cE formation we selected SDSS DR7 for our search, as its coverage includes the field as well as galaxy clusters. Using the SDSS seeing-corrected model fits, ～70 candidate cEs have been identified. The majority lie near massive neighbours and have colours consistent with stripping. But surprisingly, a few lie far from any massive galaxy, and we will follow-up these objects with deeper imaging.