A luminosity function of Lyα-emitting galaxies at z ≈ 4.5

被引:101
作者
Dawson, Steve [1 ]
Rhoads, James E. [2 ]
Malhotra, Sangeeta [2 ]
Stern, Daniel [3 ]
Wang, JunXian [4 ]
Dey, Arjun [5 ]
Spinrad, Hyron [1 ]
Jannuzi, Buell T. [5 ]
机构
[1] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
[2] Arizona State Univ, Sch Earth & Space Explorat, Tempe, AZ 85287 USA
[3] CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA
[4] Univ Sci & Technol China, Ctr Astrophys, Hefei 230026, Peoples R China
[5] Kitt Peak Natl Observ, Natl Opt Astron Observ, Tucson, AZ 85726 USA
关键词
cosmology : observations; early universe; galaxies : evolution; galaxies : formation; galaxies : high-redshift;
D O I
10.1086/522908
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present a catalog of 59 z approximate to 4.5 Ly alpha-emitting galaxies spectroscopically confirmed in a campaign of Keck DEIMOS follow-up observations to candidates selected in the Large Area Ly alpha ( LALA) narrowband imaging survey. We targeted 97 candidates for spectroscopic follow-up; by accounting for the variety of conditions under which we performed spectroscopy, we estimate a selection reliability of similar to 76%. Together with our previous sample of Keck LRIS confirmations, the 59 sources confirmed herein bring the total catalog to 73 spectroscopically confirmed z approximate to 4.5 Ly alpha-emitting galaxies in the approximate to 0.7 deg(2) covered by the LALA imaging. As with the Keck LRIS sample, we find that a nonnegligible fraction of the confirmed Ly alpha lines have rest-frame equivalent widths (W-lambda(rest)) that exceed the maximum predicted for normal stellar populations: 17%-31%( 93% confidence) of the detected galaxies show W-lambda(rest) > 190 angstrom, and 12%-27% ( 90% confidence) show W-lambda(rest) > 240 angstrom. We construct a luminosity function of z approximate to 4.5 Ly alpha emission lines for comparison to Ly alpha luminosity functions spanning 3.1 < z < 6.6. We find no significant evidence for Ly alpha luminosity function evolution from z approximate to 3 to z approximate to 6. This result supports the conclusion that the intergalactic medium remains largely reionized from the local universe out to z approximate to 6.5. It is somewhat at odds with the pronounced drop in the cosmic star formation rate density recently measured between z similar to 3 and z similar to 6 in continuum-selected Lyman-break galaxies, and therefore potentially sheds light on the relationship between the two populations.
引用
收藏
页码:1227 / 1240
页数:14
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