Open AccessX‐ray scaling properties of early‐type galaxies
Author(s) -
O'Sullivan Ewan,
Ponman Trevor J.,
Collins Ross S.
Publication year - 2003
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2003.06396.x
Subject(s) - physics , astrophysics , rosat , galaxy , surface brightness , halo , galaxy group , astronomy , lenticular galaxy , peculiar galaxy , surface brightness fluctuation , luminosity , scaling , galaxy cluster , geometry , mathematics
We present an analysis of 39 X‐ray luminous early‐type galaxies observed with the ROSAT PSPC. Using multicomponent spectral and spatial fits to these data, we have measured halo abundance, temperature, luminosity and surface brightness profile. We compare these measurements to similar results from galaxy groups and clusters, fitting a number of relations commonly used in the study of these larger objects. In particular, we find that the σ– T X relation for our sample is similar to that reported for clusters, consistent with β spec = 1 , and that the L X – T X relation has a steep slope (gradient 4.8 ± 0.7 ) comparable with that found for galaxy groups. Assuming isothermality, we construct three‐dimensional models of our galaxies, allowing us to measure gas entropy. We find no correlation between gas entropy and system mass, but do find a trend for low‐temperature systems to have reduced gas fractions. We conclude that the galaxies in our sample are likely to have developed their haloes through galaxy winds, influenced by their surrounding environment.