A high fraction of Lyα emitters among galaxies with extreme emission line ratios at z ∼ 2

Journal Article · Mon Oct 10 04:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/830/1/52· OSTI ID:22868606

Erb, Dawn K. ^[1]; Pettini, Max ^[2]; Steidel, Charles C.; Strom, Allison L. ^[3]; Rudie, Gwen C. ^[4]; Trainor, Ryan F. ^[5]; Shapley, Alice E. ^[6]

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1. Center for Gravitation, Cosmology and Astrophysics, Department of Physics, University of Wisconsin Milwaukee, 3135 N. Maryland Avenue, Milwaukee, WI 53211 (United States)
2. Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)
3. Cahill Center for Astrophysics, California Institute of Technology, 1216 E. California Boulevard, MS 249-17, Pasadena, CA 91125 (United States)
4. Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
5. Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720 (United States)
6. University of California, Los Angeles, Department of Physics and Astronomy, 430 Portola Plaza, Los Angeles, CA 90095 (United States)

Star-forming galaxies form a sequence in the [O iii] λ5007/Hβ versus [N ii] λ6584/Hα diagnostic diagram, with low-metallicity, highly ionized galaxies falling in the upper left corner. Drawing from a large sample of UV-selected star-forming galaxies at z∼2 with rest-frame optical nebular emission line measurements from Keck-MOSFIRE, we select the extreme ∼5% of the galaxies lying in this upper left corner, requiring log([N ii]/Hα) ⩽−1.1 and log([O iii]/Hβ) ⩾ 0.75. These cuts identify galaxies with 12+log(O/H)≲8.0, when oxygen abundances are measured via the O3N2 diagnostic. We study the Lyα properties of the resulting sample of 14 galaxies. The mean (median) rest-frame Lyα equivalent width is 39 (36) Å, and 11 of the 14 objects (79%) are Lyα emitters (LAEs) with W{sub Lyα} >20 A-ring . We compare the equivalent width distribution of a sample of 522 UV-selected galaxies at 2.0

• OSTI ID: 22868606
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 830; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COMPARATIVE EVALUATIONS
DENSITY
DISTRIBUTION
ELEMENT ABUNDANCE
EMISSION
GALACTIC EVOLUTION
GALAXIES
HYDROGEN
IONIZATION
METALLICITY
MULTIPLE SCATTERING
OXYGEN
RED SHIFT
SPECTRA
STARS