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Lyα-emitting galaxies at 0.2 < z < 0.35 from GALEX spectroscopy
被引:85
作者:
Deharveng, Jean-Michel
[1
]
Small, Todd
[2
]
Barlow, Tom A.
[2
]
Peroux, Celine
[1
]
Milliard, Bruno
[1
]
Friedman, Peter G.
[2
]
Martin, D. Christopher
[2
]
Morrissey, Patrick
[2
]
Schiminovich, David
[3
]
Forster, Karl
[2
]
Seibert, Mark
[2
]
Wyder, Ted K.
[2
]
Bianchi, Luciana
Donas, Jose
[1
]
Heckman, Timothy M.
[4
]
Lee, Young-Wook
[5
]
Madore, Barry F.
[6
]
Neff, Susan G.
[7
]
Rich, R. Michael
[8
]
Szalay, Alex S.
[4
]
Welsh, Barry Y.
[9
]
Yi, Sukyoung K.
[5
]
机构:
[1] Univ Aix Marseille 1, CNRS, UMR 6110, Astrophys Lab, F-13376 Marseille 12, France
[2] CALTECH, Pasadena, CA 91125 USA
[3] Columbia Univ, Dept Astron, New York, NY 10027 USA
[4] Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA
[5] Yonsei Univ, Ctr Space Astrophys, Seoul 120749, South Korea
[6] Observ Carnegie Inst Washington, Pasadena, CA 91101 USA
[7] NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA
[8] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA
[9] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA
关键词:
galaxies : evolution;
galaxies : ISM;
galaxies : luminosity function;
mass function;
galaxies : starburst;
ultraviolet : galaxies;
D O I:
10.1086/587953
中图分类号:
P1 [天文学];
学科分类号:
0704 ;
摘要:
We have used the GALEX (Galaxy Evolution Explorer) spectroscopic survey mode, with a resolution of similar to 8 angstrom in the far-ultraviolet (FUV; 1350-1750 angstrom) and similar to 20 angstrom in the near-ultraviolet (NUV; 1950-2750 angstrom) for a systematic search of Ly alpha-emitting galaxies at low redshift. Our aim is to fill a gap between high-redshift surveys and a small set of objects studied in detail in the nearby universe. A blind search of 7018 spectra extracted in five deep exposures (5.65 deg(2)) has resulted in 96 Ly alpha-emitting galaxy candidates in the FUV domain after accounting for broad-line AGNs. The Ly alpha equivalent widths (EWs) are consistent with stellar population model predictions and show no trends as a function of UV color or UV luminosity, with the exception of a possible decrease in the most luminous objects that may be due to small-number statistics. The objects' distribution in EW is similar to that at z similar to 3, but their fraction among star-forming galaxies is smaller. Avoiding uncertain candidates, a subsample of 66 objects in the range 0.2 < z < 0.35 has been used to build a Ly alpha luminosity function (LF). The incompleteness due to objects with significant Ly alpha emission but a UV continuum too low for spectral extraction has been evaluated. A comparison with H alpha LFs in the same redshift domain is consistent with an average Ly alpha/H alpha of similar to 1 in about 15% of the star-forming galaxies. A comparison with high-redshift Ly alpha LFs implies an increase of the Ly alpha luminosity density by a factor of about 16 from z similar to 0.3 to z similar to 3. By comparison with the factor of 5 increase in the UV luminosity density in the same redshift range, this suggests an increase of the average Ly alpha escape fraction with redshift.
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页码:1072 / 1082
页数:11
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