Spectroscopic evolution of dusty starburst galaxies in distant clusters

Citation
Y. Shioya et al., Spectroscopic evolution of dusty starburst galaxies in distant clusters, ASTROPHYS J, 558(1), 2001, pp. 42-55
Citations number
52
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
558
Issue
1
Year of publication
2001
Part
1
Pages
42 - 55
Database
ISI
SICI code
0004-637X(20010901)558:1<42:SEODSG>2.0.ZU;2-2
Abstract
By using a one-zone chemical and spectrophotometric evolution model of a di sk galaxy undergoing a dusty starburst, we investigate numerically the opti cal spectroscopic properties in order to explore galaxy evolution in distan t clusters. We adopt an assumption that the degree of dust extinction (repr esented by Av) depends on the ages of starburst populations in such a way t hat younger stars have larger Av (originally referred to as selective dust extinction by Poggianti & Wu). In particular, we investigate how the time e volution of the equivalent widths of [O II] lambda 3727 and H delta are con trolled by the adopted age dependence. This leads to the following three ma in results: (1) If a young stellar population (with an age of similar to 10 (6) yr) is more heavily obscured by dust than an old one (> 10(8) yr), the galaxy can show an " e(a) " spectrum characterized by strong H delta absorp tion and relatively modest [O II] emission. (2) A dusty starburst galaxy wi th an e(a) spectrum can evolve into a poststarburst galaxy with an a + k (o r k + a) spectrum 0.2 Gyr after the starburst and then into a passive one w ith a k-type spectrum 1 Gyr after the starburst. This result clearly demons trates an evolutionary link between galaxies with different spectral classe s [i.e., e(b), e(a), a + k, k + a, and k]. (3) A dusty starburst galaxy can show an a + k or k + a spectrum even in the dusty starburst phase if the a ge-dependence of dust extinction is rather weak; i.e., if young starburst p opulations with different ages (less than or equal to 10(7) yr) are uniform ly obscured by dust.