We report the spectroscopic confirmation of a sub-mm galaxy (SMG) at z=4.547 with an estimated L_IR=0.5-2.0x10^13 L_sun. The spectra, mid-IR, and X-ray properties indicate the bolometric luminosity is dominated by star formation at a rate of >1000M_sun per yr. Multiple, spatially separated components are visible in the Ly-Alpha line with an observed velocity difference of up to 380 km/sec and the object morphology indicates a merger. The best fit spectral energy distribution and spectral line indicators suggest the object is 2-8 Myr old and contains >10^10 M_sun of stellar mass. This object is a likely progenitor for the massive early type systems seen at z~2.
@article{arxiv.0806.0657,
title = {Spectroscopic Confirmation Of An Extreme Starburst At Redshift 4.547},
author = {Peter Capak and C. L. Carilli and N. Lee and T. Aldcroft and H. Aussel and E. Schinnerer and G. W. Wilson and M. S. Yun and A . Blain and M. Giavalisco and O. Ilbert and J. Kartaltepe and K. -S. Lee and H. McCracken and B. Mobasher and M. Salvato and S. Sasaki and K. S. Scott and K. Sheth and Y. Shioya and D. Thompson and M. Elvis and D. B. Sanders and N. Z. Scoville and Y. Tanaguchi},
journal= {arXiv preprint arXiv:0806.0657},
year = {2009}
}