Journal or Book Title
The Astrophysical Journal Letters
Based on broadband/narrowband photometry and Keck DEIMOS spectroscopy, we report a redshift of z = 4.64+0.06 –0.08 for AzTEC/COSMOS 1, the brightest submillimeter galaxy (SMG) in the AzTEC/COSMOS field. In addition to the COSMOS-survey X-ray to radio data, we report observations of the source with Herschel/PACS (100, 160 μm), CSO/SHARC II (350 μm), and CARMA and PdBI (3 mm). We do not detect CO(5 → 4) line emission in the covered redshift ranges, 4.56-4.76 (PdBI/CARMA) and 4.94-5.02 (CARMA). If the line is within this bandwidth, this sets 3σ upper limits on the gas mass to 8 × 109 M and 5 × 1010 M , respectively (assuming similar conditions as observed in z ~ 2 SMGs). This could be explained by a low CO-excitation in the source. Our analysis of the UV-IR spectral energy distribution of AzTEC 1 shows that it is an extremely young (50 Myr), massive (M * ~ 1011 M ), but compact (2 kpc) galaxy, forming stars at a rate of ~1300 M yr–1. Our results imply that AzTEC 1 is forming stars in a "gravitationally bound" regime in which gravity prohibits the formation of a superwind, leading to matter accumulation within the galaxy and further generations of star formation.
Smolcic, V; Capak, P; Ilbert, O; Blain, AW; Salvato, M; Aretxaga, I; Schinnerer, E; Masters, D; Moric, I; Riechers, DA; Sheth, K; Aravena, M; Aussel, H; Aguirre, J; Berta, S; Carilli, CL; Civano, F; Fazio, G; Huang, J; Hughes, D; Kartaltepe, J; Koekemoer, AM; Kneib, J-P; LeFloc'h, E; Lutz, D; McCracken, H; Mobasher, B; Murphy, E; Pozzi, F; Riguccini, L; Sanders, DB; Sargent, M; Scott, KS; Scoville, NZ; Taniguchi, Y; Thompson, D; Willot, C; Wilson, G; and Yun, Min, "THE REDSHIFT AND NATURE OF AzTEC/COSMOS 1: A STARBURST GALAXY AT z = 4.6*" (2011). The Astrophysical Journal Letters. 1114.