Photometric Signatures of Starbursts in Interacting Galaxies and the Butcher-Oemler Effect

Author(s)

Karl D. Rakos, Thomas I. Maindl, James M. Schombert

Abstract

This paper presents new and synthetic narrowband photometry of

ellipticals, spirals, Seyferts, and interacting galaxies in an attempt

to identify the cause of the unusually high fraction of blue cluster

galaxies in distance clusters (Butcher-Oemler effect). The properties

and distribution of the low-redshift sample specifically points to

starbursts as the origin of the blue narrowband colors in interacting

Arp galaxies. Comparison between theoretical models and multicolor

diagrams, particularly 4000 A break colors, indicates a photometric

signature that differs from both normal disk galaxy star formation and

nonthermal components. This photometric signature is absent for the

Butcher-Oemler galaxies whose general color distribution, compared to

present-day clusters, is consistent with a majority of the blue

population involved in normal star formation rates (spiral-like) with

the addition of a small fraction of bright, blue interacting/merger

systems. This photometric picture of the Butcher-Oemler galaxies is in

agreement with the morphological evidence from Hubble Space Telescope

imaging.

Organisation(s)

Department of Astrophysics

External organisation(s)

University of Vienna

Pages

122

Publication date

07-1996

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

Portal url