Luminosity function of galaxy systems: From single galaxies and small groups to rich clusters

Journal Article · Sat Sep 15 04:00:00 EDT 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157327· OSTI ID:5636597

Bahcall, N A

The luminosity function (LF) of galaxy systems: from single galaxies and small groups to rich clusters: is determined. First, the rich-cluster luminosity function is determined . Then, a ''groupings'' luminosity function is found which includes all systems from small groups to rich clusters; and finaly a general luminosity function of all galaxy systems (AGS), from single galaxies to rich clusters is estimated. The catalogs of Abell (rich clusters) and Turner and Gott (groups, singles) are used.1.6 x 10/sup -7/ systems Mpc/sup -3/ (10/sup 12/ L/sub sun/)/sup -1/. The ''break'' at L/sub 0/approx. =1 x 10/sup 13/ L/sub sun/ occurs at the typical luminosity of rich Abell-type clusters. The slope ..cap alpha.. is found to depend on the density enhancement factor with which the groups are selected, but the dependence is relatively weak. The exponential decay at the bright end (rich clusters) has an equivalent power-law slope of approximately -5, i.e., eta (L) proportional L/sup -5/. The functional form of the LF is consistent with the Press-Schechter model of galaxy formation, and with the recent Silk-white model (predicted slope of -2.0). When single galaxies are added to the groupings luminosity function, the AGS luminosity function can be roughly described as eta (L) =1.6 x 10/sup -7/(L/L/sub 0/)/sup -2/ exp (-L/L/sub 0/)(1+1.6 x 10/sup 10//L)/sup -0.75/ Mpc/sup -3/(10/sup 12/ L/sub sun/)/sup -1/ with L/sub 0/=110/sup 13/ L/sub sun/. This function approaches Schechter's field galaxy LF at low luminosities, and the groupings function at high luminosities.

• Research Organization: Weizmann Institute of Science, Rehovot, Israel
• OSTI ID: 5636597
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 232:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
GALAXIES
GALAXY CLUSTERS
LUMINOSITY
OPTICAL PROPERTIES
PHOTOMETRY
PHYSICAL PROPERTIES
X-RAY GALAXIES