A CANDELS WFC3 GRISM STUDY OF EMISSION-LINE GALAXIES AT z {approx} 2: A MIX OF NUCLEAR ACTIVITY AND LOW-METALLICITY STAR FORMATION
- University of California Observatories/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
- Astronomy Department, University of Minnesota, Minneapolis, MN 55455 (United States)
- Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States)
- Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom)
- Department of Physics, Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)
- Spitzer Science Center, Caltech, Pasadena, CA 91125 (United States)
- National Optical Astronomical Observatories, Tucson, AZ 85719 (United States)
- Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
- Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, EH9 3HJ (United Kingdom)
- Department of Physics and Astronomy, Texas A and M University, 4242 TAMU, College Station, TX 77843 (United States)
We present Hubble Space Telescope Wide Field Camera 3 (WFC3) slitless grism spectroscopy of 28 emission-line galaxies at z {approx} 2, in the GOODS-S region of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey. The high sensitivity of these grism observations, with >1{sigma} detections of emission lines to f > 2.5 Multiplication-Sign 10{sup -18} erg s{sup -1} cm{sup -2}, means that the galaxies in the sample are typically {approx}7 times less massive (median M{sub *} = 10{sup 9.5} M{sub Sun }) than previously studied z {approx} 2 emission-line galaxies. Despite their lower mass, the galaxies have [O III]/H{beta} ratios which are very similar to previously studied z {approx} 2 galaxies and much higher than the typical emission-line ratios of local galaxies. The WFC3 grism allows for unique studies of spatial gradients in emission lines, and we stack the two-dimensional spectra of the galaxies for this purpose. In the stacked data the [O III] emission line is more spatially concentrated than the H{beta} emission line with 98.1% confidence. We additionally stack the X-ray data (all sources are individually undetected), and find that the average L{sub [OIII]}/L{sub 0.5-10keV} ratio is intermediate between typical z {approx} 0 obscured active galaxies and star-forming galaxies. Together the compactness of the stacked [O III] spatial profile and the stacked X-ray data suggest that at least some of these low-mass, low-metallicity galaxies harbor weak active galactic nuclei.
- OSTI ID:
- 22004435
- Journal Information:
- Astrophysical Journal, Vol. 743, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE WFC3 INFRARED SPECTROSCOPIC PARALLEL (WISP) SURVEY
SPATIALLY RESOLVED HST GRISM SPECTROSCOPY OF A LENSED EMISSION LINE GALAXY AT z {approx} 1