DUST OBSCURATION IN LYMAN BREAK GALAXIES AT z {approx} 4
- Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China)
- Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States)
Measuring star formation rates (SFRs) in high-z galaxies with their rest-frame ultraviolet (UV) continuum can be uncertain because of dust obscuration. Prior studies had used the submillimeter emission at 850 {mu}m to determine the intrinsic SFRs of rest-frame UV-selected galaxies, but the results suffered from the low sensitivity and poor resolution ({approx}15''). Here, we use ultradeep Very Large Array 1.4 GHz images with {approx}1''-2'' resolutions to measure the intrinsic SFRs. We perform stacking analyses in the radio images centered on {approx}3500 Lyman break galaxies (LBGs) at z {approx} 4 in the Great Observatories Origins Deep Survey-North and South fields selected with Hubble Space Telescope/Advanced Camera for Surveys data. The stacked radio flux is very low, 0.08 {+-} 0.15 {mu}Jy, implying a mean SFR of 6 {+-} 11 M{sub sun} yr{sup -1}. This is comparable to the uncorrected mean UV SFRs of {approx}5 M{sub sun} yr{sup -1}, implying that the z {approx} 4 LBGs have little dust extinction. The low SFR and dust extinction support the previous results that z {approx} 4 LBGs are in general not submillimeter galaxies. We further show that there is no statistically significant excess of dust-hidden star-forming components within {approx}22 kpc from the LBGs.
- OSTI ID:
- 21464648
- Journal Information:
- Astrophysical Journal, Vol. 722, Issue 2; Other Information: DOI: 10.1088/0004-637X/722/2/1051; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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