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

Journal Article · Sun Oct 20 04:00:00 EDT 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/776/2/75· OSTI ID:22270759

Feldmeier, John J. ^[1]; Hagen, Alex; Ciardullo, Robin; Gronwall, Caryl; Hagen, Lea M. Z. ^[2]; Gawiser, Eric; Kurczynski, Peter ^[3]; Guaita, Lucia ^[4]; Bond, Nicholas A. ^[5]; Acquaviva, Viviana ^[6]; Blanc, Guillermo A. ^[7]; Orsi, Alvaro ^[8]

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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)

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 if 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.

• OSTI ID: 22270759
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 776; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTRONOMY
ASTROPHYSICS
BRIGHTNESS
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
COSMOLOGY
FLUCTUATIONS
GALAXIES
HYDROGEN
LYMAN LINES
MONTE CARLO METHOD
PHOTOMETRY
PHOTON EMISSION
RED SHIFT
SURFACES