On Near-Infrared H-Alpha Searches for High-Redshift Galaxies
Abstract
The lack of success of Lyman-alpha searches for high-redshift (z>2) field galaxies may be due to extinction by dust, suggesting that surveys based on lines of longer wavelength, particularly H-alpha, may be more effective. To test the dust hypothesis we have undertaken deep broad- (K') and narrow-band (5000 km/s, 2.177 micron) imaging of the field towards the quasar PHL957, in an attempt to detect H-alpha emission from a known galaxy of redshift z=2.313. We cover an area of 4.9 square arcmin (0.28 h^{-2}Mpc^2) to a 4-sigma limiting narrow-band flux f=2.7x10^{-16}erg/s/cm^2, a factor of several deeper than previously published surveys. We detect the H-alpha+[N II] emission line in this galaxy at the 3.3-sigma level, inferring a star formation rate of 18 h^{-2} solar masses per year. This is a factor only a few times larger than the rate seen in some Sc galaxies today. The faint flux level reached in this work demonstrates the promise of narrow-band imaging in the near-infrared as a technique for finding normal galaxies at high redshifts.
Cite
@article{arxiv.astro-ph/9501026,
title = {On Near-Infrared H-Alpha Searches for High-Redshift Galaxies},
author = {A. J. Bunker and S. J. Warren and P. C. Hewett and D. L. Clements},
journal= {arXiv preprint arXiv:astro-ph/9501026},
year = {2015}
}
Comments
6 pages of LaTex using mn.sty (MNRAS style). Figure 1 is an image obtainable from the Authors by FTP. Contact [email protected] for more details. Figure 2 is a Z-compressed, uuencoded postscript graph.