An ultraviolet ultra-luminous lyman break galaxy at Z = 2.78 in NDWFS boötes field

Fuyan Bian, Xiaohui Fan, Linhua Jiang, Arjun Dey, Richard F. Green, Roberto Maiolino, Fabian Walter, Ian McGreer, Ran Wang, Yen Ting Lin

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

We present one of the most ultraviolet (UV) luminous Lyman break galaxies (LBGs; J1432+3358) at z = 2.78, discovered in the NOAO Deep Wide-Field Survey Boötes field. The R-band magnitude of J1432+3358 is 22.29AB, more than two magnitudes brighter than typical L* LBGs at this redshift. The deep z-band image reveals two components of J1432+3358 separated by 10 with a flux ratio of 3:1. The high signal-to-noise ratio rest-frame UV spectrum shows Lyα emission line and interstellar medium absorption lines. The absence of N V and C IV emission lines, and the non-detection in X-ray and radio wavelengths and mid-infrared (MIR) colors indicates weak or no active galactic nuclei (<10%) in this galaxy. The galaxy shows a broader line profile, with a FWHM of about 1000kms-1 and a larger outflow velocity (500kms-1) than those of typical z 3 LBGs. The physical properties are derived by fitting the spectral energy distribution (SED) with stellar synthesis models. The dust extinction, E(B - V) = 0.12, is similar to that in normal LBGs. The star formation rates (SFRs) derived from the SED fitting and the dust-corrected UV flux are consistent with each other, 300 M yr-1, and the stellar mass is (1.3 ± 0.3) × 1011 M . The SFR and stellar mass in J1432+3358 are about an order of magnitude higher than those in normal LBGs. The SED-fitting results support that J1432+3358 has a continuous star formation history, with a star formation episode of 6.3 × 108yr. The morphology of J1432+3358 and its physical properties suggest that J1432+3358 is in an early phase of a 3:1 merger process. The unique properties and the low space number density (10 -7Mpc-3) are consistent with the interpretation that such galaxies are either found in a short unobscured phase of the star formation or that a small fraction of intensive star-forming galaxies are unobscured.

Original languageEnglish (US)
Article number139
JournalAstrophysical Journal
Volume757
Issue number2
DOIs
StatePublished - Oct 1 2012

Keywords

  • galaxies: high-redshift
  • galaxies: star formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Bian, F., Fan, X., Jiang, L., Dey, A., Green, R. F., Maiolino, R., Walter, F., McGreer, I., Wang, R., & Lin, Y. T. (2012). An ultraviolet ultra-luminous lyman break galaxy at Z = 2.78 in NDWFS boötes field. Astrophysical Journal, 757(2), [139]. https://doi.org/10.1088/0004-637X/757/2/139