Search for HI in E+A galaxies

Citation
Tc. Chang et al., Search for HI in E+A galaxies, ASTRONOM J, 121(4), 2001, pp. 1965-1973
Citations number
41
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMICAL JOURNAL
ISSN journal
00046256 → ACNP
Volume
121
Issue
4
Year of publication
2001
Pages
1965 - 1973
Database
ISI
SICI code
0004-6256(200104)121:4<1965:SFHIEG>2.0.ZU;2-Q
Abstract
We present the results of H I line and radio continuum observations of five nearby E+A galaxies. These galaxies have spectra that are dominated by a y oung stellar component but lack the emission lines characteristic of signif icant ongoing star formation. They are selected from a unique sample of 21 E+A's identified by Zabludoff et al. in their spectroscopic search (publish ed in 1996) for E+A galaxies using the Las Campanas Redshift Survey, in whi ch over 11,000 nearby galaxies were examined. The five E+A galaxies span a range of environments: three are in the field, and two are in clusters. Onl y one system was detected in H I emission, the field E+A galaxy EA 1, with a total flux of 0.30 +/- 0.02 Jy km s(-1) and an H I mass of 3.5 +/- 0.2 x 10(9) h(-2) M-.. The H I morphology and kinematics of EA 1 suggest a galaxy -galaxy interaction, with a dynamical age of similar to6 x 10(8) h(-1) yr i nferred from the H I tail lengths and velocities. This age estimate is cons istent with the interpretation drawn from optical spectroscopy that starbur sts in E+A galaxies began (and subsequently ended) within the last 10(9) yr . Our H I detection limits are such that if the other E+A's in our sample h ad the H I properties of EA 1, we would have detected (or marginally detect ed) them. We conclude that E+A galaxies have a range of H I properties. Non e of the galaxies were detected in radio continuum emission, with upper lim its to the radio power of similar to 10(21) h(-2) W Hz(-1). Our limits excl ude the possibility that these E+A's are dust-enshrouded massive starburst galaxies, but they are insufficient to exclude modest star formation rates of less than a few h(-2) M-. yr(-1).