FIRST SPECTROSCOPIC MEASUREMENTS OF [O III] EMISSION FROM Ly{alpha} SELECTED FIELD GALAXIES AT z {approx} 3.1
- School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
- George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station, TX 77843 (United States)
- INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Firenze (Italy)
- ZAH, Landessternwarte, Universitaet Heidelberg, Koenigstuhl 12, D-69117 Heidelberg (Germany)
- Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany)
- Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
- Department of Astronomy, 351 Tate Laboratory of Physics, 116 Church Street, S. E., University of Minnesota, Minneapolis, MN 55455 (United States)
We present the first spectroscopic measurements of the [O III] 5007 A line in two z {approx} 3.1 Ly{alpha} emitting galaxies (LAEs) using the new near-infrared instrument LUCIFER1 on the 8.4 m Large Binocular Telescope. We also describe the optical imaging and spectroscopic observations used to identify these LAEs. Using the [O III] line we have measured accurate systemic redshifts for these two galaxies, and discovered a velocity offset between the [O III] and Ly{alpha} lines in both, with the Ly{alpha} line peaking 342 and 125 km s{sup -1} redward of the systemic velocity. These velocity offsets imply that there are powerful outflows in high-redshift LAEs. They also ease the transmission of Ly{alpha} photons through the interstellar medium and intergalactic medium around the galaxies. By measuring these offsets directly, we can refine both Ly{alpha}-based tests for reionization, and Ly{alpha} luminosity function measurements where the Ly{alpha} forest affects the blue wing of the line. Our work also provides the first direct constraints on the strength of the [O III] line in high-redshift LAEs. We find [O III] fluxes of 7 and 36 x10{sup -17} erg s{sup -1} cm{sup -2} in two z {approx} 3.1 LAEs. These lines are strong enough to dominate broadband flux measurements that include the line (in this case, K{sub s} -band photometry). Spectral energy distribution fits that do not account for the lines would therefore overestimate the 4000 A (and/or Balmer) break strength in such galaxies, and hence also the ages and stellar masses of such high-z galaxies.
- OSTI ID:
- 21574805
- Journal Information:
- Astrophysical Journal, Vol. 730, Issue 2; Other Information: DOI: 10.1088/0004-637X/730/2/136; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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