A SEARCH FOR LYMAN BREAK GALAXIES IN THE CHANDRA DEEP FIELD SOUTH USING SWIFT ULTRAVIOLET/OPTICAL TELESCOPE

Journal Article · Sat Oct 01 04:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/739/2/98; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21587457

Basu-Zych, Antara R; Hornschemeier, Ann E ^[1]; Hoversten, Erik A; Gronwall, Caryl ^[2]; Lehmer, Bret ^[3]

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1. NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States)
2. Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)
3. Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

While the Swift satellite is primarily designed to study gamma-ray bursts, its ultraviolet and optical imaging and spectroscopy capabilities are also being used for a variety of scientific programs. In this study, we use the UV/Optical Telescope (UVOT) instrument on board Swift to discover 0.5 < z < 2 Lyman break galaxies (LBGs). UVOT has covered {approx}266 arcmin{sup 2} at >60 ks exposure time, achieving a limiting magnitude of u < 24.5, in the Chandra Deep Field South (CDF-S). Applying UVOT near-ultraviolet color selection, we select 50 UV-dropouts from this UVOT CDF-S data. We match the selected sources with available multiwavelength data from Great Observatories Origins Deep Survey (GOODS) South, Multiwavelength Survey by Yale-Chile, and COMBO-17 to characterize the spectral energy distributions for these galaxies and determine stellar masses, star formation rates (SFRs), and dust attenuations. We compare these properties for LBGs selected in this paper versus z {approx} 3 LBGs and other CDF-S galaxies in the same redshift range (0.5 < z < 2), identified using photometric redshift techniques. The z {approx} 1 LBGs have stellar masses of (logM{sub *}/M{sub sun}) = 9.4 {+-} 0.6, which is slightly lower than z {approx} 3 LBGs ((logM{sub *}/Ms{sub un}) = 10.2 {+-} 0.4) and slightly higher compared with the z {approx} 1 CDF-S galaxies ((logM{sub *}/M{sub sun}) = 8.7 {+-} 0.7). Similarly, our sample of z {approx} 1 LBGs has SFRs (derived using both ultraviolet and infrared data, where available) of (logSFR/(M{sub sun} yr{sup -1})) = 0.7 {+-} 0.6, nearly an order of magnitude lower than z {approx} 3 LBGs ((logSFR/M{sub sun} yr{sup -1}) = 1.5 {+-} 0.4), but slightly higher than the comparison z {approx} 1 sample of CDF-S galaxies ((logSFR/M{sub sun} yr{sup -1}) = 0.2 {+-} 0.7). We find that our z {approx} 1 UV-dropouts have (A{sub FUV}) = 2.0 {+-} 1.0, which is higher than z {approx} 3 LBGs ((A{sub FUV}) = 1.0 {+-} 0.5), but similar to the distribution of dust attenuations in the other CDF-S galaxies ((A{sub FUV}) {approx} 2.8 {+-} 1.5). Using the GOODS-South multiwavelength catalog of galaxies, we simulate a larger and fainter sample of LBGs to compare their properties with those of the UVOT-selected LBG sample. We conclude that UVOT can be useful for finding and studying the bright end of 0.5 < z < 2.0 LBGs.

• OSTI ID: 21587457
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 739; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATTENUATION
COSMIC GAMMA BURSTS
COSMIC RADIATION
DUSTS
ELECTROMAGNETIC RADIATION
ENERGY SPECTRA
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
IONIZING RADIATIONS
MASS
PRIMARY COSMIC RADIATION
RADIATIONS
SPECTRA
STARS
ULTRAVIOLET RADIATION