Probing Extreme-EW Lyman-a Emitting Galaxy Populations Using A Broad Band Selection Technique.
Abstract
The emission mechanisms that drive extreme-EW Lyman-a emitting galaxies (LAEs), though studied for the last decade, still are not well understood. The explanation for their pronounced Lyman-a emission has ranged from population III stars, to obscured AGN, to collapsing gas clouds. Since only a small number of these systems have been studied in depth, it is unknown whether or not LAEs are simply a stage in typical galaxy evolution or a rare and more peculiar phenomenon. Most studies of LAEs have been completed using narrow-band filter searches probing a small redshift range, and thus a small volume. We have developed a broad-band selection technique to probe the high equivalent width end of the LAE population. This method probes a much larger volume and redshift range. We have used CFHT-LS Deep 3 Field photometry to select LAE candidates for follow-up spectroscopy using WIYN/Hydra multi-object spectrograph. We have confirmed 30 strong LAEs in the CFHT-LS Deep 3 with line fluxes between 5e-17 and 8e-16 ergs/(cm2 s), one QSO, and 2 low redshift Hb -O[III] emitters out of 52 photometrically selected candidates. These LAE systems exhibit narrow emission lines and do not display He II or CIV emission at the depth of a 3-s limit of 1e-17 ergs/(cm2 s Å) with 7 hours of exposure time on WIYN/Hydra.
- Publication:
-
American Astronomical Society Meeting Abstracts #217
- Pub Date:
- January 2011
- Bibcode:
- 2011AAS...21743024B