Rest-frame Mid-infrared Detection of an Extremely Luminous Lyman Break Galaxy with the Spitzer Infrared Spectrograph (irs)

We present the first rest-frame 4 m detection of a Lyman break galaxy. The data were obtained using the 16 m imaging capability of the Spitzer Infrared Spectrograph. The target object, J134026.44+634433.2, is an extremely luminous Lyman break galaxy at z 1⁄4 2:79, first identified in Sloan Digital Sky Survey (SDSS) spectra (as reported by Bentz et al.). The source is strongly detected with a flux of 0:94 0:02 mJy. Combining Spitzer and SDSS photometry with supporting ground-based Jand K-band data, we show that the spectral energy distribution is consistent with an actively star-forming galaxy. We also detect other objects in the Spitzer field of view, including a very red mid-infrared source. We find no evidence of a strong lens among the mid-infrared sources. Subject headinggs: cosmology: observations — galaxies: evolution — galaxies: high-redshift — galaxies: individual (J134026.44+634433.2) — infrared: galaxies