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.
The Redshift and Nature of AzTEC/COSMOS 1: A Starburst Galaxy at z = 4.6 / Smolčić V.; Capak P.; Ilbert O.; Blain A. W.; Salvato M.; Aretxaga I.; Schinnerer E.; Masters D.; Morić I.; Riechers D. A.; Sheth K.; Aravena M.; Aussel H.; Aguirre J.; Berta S.; Carilli C. L.; Civano F.; Fazio G.; Huang J.; Hughes D.; Kartaltepe J.; Koekemoer A. M.; Kneib J.-P.; LeFloc'h E.; Lutz D.; McCracken H.; Mobasher B.; Murphy E.; Pozzi F.; Riguccini L.; Sanders D. B.; Sargent M.; Scott K. S.; Scoville N. Z.; Taniguchi Y.; Thompson D.; Willott C.; Wilson G.; Yun M.. - In: THE ASTROPHYSICAL JOURNAL LETTERS. - ISSN 2041-8205. - STAMPA. - 731:(2011), pp. L27-L32. [10.1088/2041-8205/731/2/L27]
The Redshift and Nature of AzTEC/COSMOS 1: A Starburst Galaxy at z = 4.6
POZZI, FRANCESCA;
2011
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
