EVOLUTION OF THE Halpha LUMINOSITY FUNCTION
- Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
- Brown University, Department of Physics, Box 1843, Providence, RI 02912 (United States)
The Smithsonian Hectospec Lensing Survey (SHELS) is a window on the star formation history over the last 4 Gyr. SHELS is a spectroscopically complete survey for R{sub tot} < 20.3 over 4 square{sup 0}. We use the 10k spectra to select a sample of pure star-forming galaxies based on their Halpha emission line. We use the spectroscopy to determine extinction corrections for individual galaxies and to remove active galaxies in order to reduce systematic uncertainties. We use the large volume of SHELS with the depth of a narrowband survey for Halpha galaxies at z approx 0.24 to make a combined determination of the Halpha luminosity function at z approx 0.24. The large area covered by SHELS yields a survey volume big enough to determine the bright end of the Halpha luminosity function from redshift 0.100 to 0.377 for an assumed fixed faint-end slope alpha = -1.20. The bright end evolves: the characteristic luminosity L* increases by 0.84 dex over this redshift range. Similarly, the star formation density increases by 0.11 dex. The fraction of galaxies with a close neighbor increases by a factor of 2-5 for L{sub Ha}lpha approx> L* in each of the redshift bins. We conclude that triggered star formation is an important influence for star-forming galaxies with Halpha emission.
- OSTI ID:
- 21392455
- Journal Information:
- Astrophysical Journal, Vol. 708, Issue 1; Other Information: DOI: 10.1088/0004-637X/708/1/534; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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