First restults from the Faint Infrared Grism Survey (FIGS): first simultaneous detection of Lyα emission and Lyman break from a galaxy at z = 7.51

Journal Article · Wed Aug 10 04:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/827/1/L14· OSTI ID:22868803

Tilvi, V.; Malhotra, S.; Rhoads, J. E.; Windhorst, R.; Pharo, J.; Joshi, B.; Yang, H. ^[1]; Pirzkal, N.; Grogin, N. A.; Koekemoer, A.; Ryan, R. ^[2]; Finkelstein, S. L. ^[3]; Zakamska, N. L. ^[4]; Christensen, L. ^[5]; Hathi, N. ^[6]; Gronwall, C. ^[7]; Cimatti, A. ^[8]; Walsh, J. ^[9]; O’Connell, R. ^[10]; Straughn, A. ^[11] ; others, and

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1. School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)
2. Space Telescope Science Institute, Baltimore, MD 21218 (United States)
3. Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States)
4. Deborah Lunder and Alan Ezekowitz Founders’ Circle Member, Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
5. 1 Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)
6. Aix Marseille Universit, CNRS, LAM (Laboratoire dÁstrophysique de Marseille) UMR 7326, F-13388, Marseille (France)
7. Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States)
8. Dipartimento di Fisica e Astronomia, Universitá di Bologna, Alma Mater Studiorum, viale Berti Pichat 6/2, I-40127 Bologna (Italy)
9. European Southern Observatory, Karl-Schwarzschild Strasse 2, D-85748 Garching (Germany)
10. Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States)
11. Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)

Galaxies at high redshifts are a valuable tool for studying cosmic dawn, therefore it is crucial to reliably identify these galaxies. Here, we present an unambiguous and first simultaneous detection of both the Lyα emission and the Lyman break from a z=7.512 ± 0.004 galaxy, observed in the Faint Infrared Grism Survey (FIGS). These spectra, taken with the G102 grism on the Hubble Space Telescope (HST), show a significant emission line detection (6σ) in two observational position angles (PAs), with Lyα line flux of 1.06±0.19×10{sup −17} erg s{sup −1} cm{sup −2}. The line flux is nearly a factor of four higher than that in the archival MOSFIRE spectroscopic observations. This is consistent with other recent observations, implying that ground-based near-infrared spectroscopy underestimates the total emission line fluxes, and if confirmed, can have strong implications for reionization studies that are based on ground-based Lyα measurements. A 4σ detection of the NV line in one PA also suggests a weak active galactic nucleus (AGN), and if confirmed, would make this source the highest-redshift AGN yet found. These observations from HST thus clearly demonstrate the sensitivity of the FIGS survey, and the capability of grism spectroscopy for studying the epoch of reionization.

• OSTI ID: 22868803
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 827; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION SPECTROSCOPY
DETECTION
GALAXIES
GALAXY NUCLEI
INFRARED SPECTRA
IONIZATION
LYMAN LINES
NEAR INFRARED RADIATION
RED SHIFT
SENSITIVITY
TELESCOPES