THE LUMINOSITY DISTRIBUTION IN GALAXY CLUSTERS - A DWARF POPULATION-DENSITY RELATION

Citation
S. Phillipps et al., THE LUMINOSITY DISTRIBUTION IN GALAXY CLUSTERS - A DWARF POPULATION-DENSITY RELATION, The Astrophysical journal, 498(2), 1998, pp. 119-123
Citations number
45
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
498
Issue
2
Year of publication
1998
Part
2
Pages
119 - 123
Database
ISI
SICI code
0004-637X(1998)498:2<119:TLDIGC>2.0.ZU;2-0
Abstract
Recent work suggests that rich clusters of galaxies commonly have larg e populations of dwarf (i.e., low-luminosity) members, that is, their luminosity function turns up to a steep slope at the faint end. This p opulation, or more particularly the relative numbers of dwarfs to gian ts, appears to be very similar for clusters of similar morphology but may vary between cluster types. We have previously suggested that dwar fs may be more common in less compact, spiral-rich clusters. Similarly , we have found evidence for population gradients across clusters, in that the dwarf population appears more spatially extended. In the pres ent Letter, we summarize the current evidence and propose, in an analo gy to the well-known morphology-density relation, that what we are see ing is a dwarf population-density relation: dwarfs are more common in lower density environments. Finally, we discuss recent semianalytic mo dels of galaxy formation in the hierarchical clustering picture, which may give clues as to the origin of our proposed relation.