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Title: SEARCHING FOR NEUTRAL HYDROGEN HALOS AROUND z ∼ 2.1 AND z ∼ 3.1 Lyα EMITTING GALAXIES

We search for evidence of diffuse Lyα emission from extended neutral hydrogen surrounding Lyα emitting galaxies (LAEs) using deep narrow-band images of the Extended Chandra Deep Field South. By stacking the profiles of 187 LAEs at z = 2.06, 241 LAEs at z = 3.10, and 179 LAEs at z = 3.12, and carefully performing low-surface brightness photometry, we obtain mean surface brightness maps that reach 9.9, 8.7, and 6.2 × 10{sup –19} erg cm{sup –2} s{sup –1} arcsec{sup –2} in the emission line. We undertake a thorough investigation of systematic uncertainties in our surface brightness measurements and find that our limits are 5-10 times larger than would be expected from Poisson background fluctuations; these uncertainties are often underestimated in the literature. At z ∼ 3.1, we find evidence for extended halos with small-scale lengths of 5-8 kpc in some but not all of our sub-samples. We demonstrate that sub-samples of LAEs with low equivalent widths and brighter continuum magnitudes are more likely to possess such halos. At z ∼ 2.1, we find no evidence of extended Lyα emission down to our detection limits. Through Monte-Carlo simulations, we also show that we would have detected large diffuse LAE halos ifmore » they were present in our data sets. We compare these findings to other measurements in the literature and discuss possible instrumental and astrophysical reasons for the discrepancies.« less
Authors:
 [1] ; ; ; ;  [2] ; ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555 (United States)
  2. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)
  3. Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States)
  4. Oskar Klein Cosmology Centre, Department of Astronomy, Stockholm University, SE-106 91 Stolkholm (Sweden)
  5. Cosmology Laboratory (Code 665), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  6. Department of Physics, New York City College of Technology, City University of New York, 300 Jay Street, Brooklyn, NY 11201 (United States)
  7. Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
  8. Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica, Av. Vicuña Mackenna 4860, Santiago (Chile)
Publication Date:
OSTI Identifier:
22270759
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 776; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; BRIGHTNESS; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; COSMOLOGY; FLUCTUATIONS; GALAXIES; HYDROGEN; LYMAN LINES; MONTE CARLO METHOD; PHOTOMETRY; PHOTON EMISSION; RED SHIFT; SURFACES