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.
Smolč, ić, V., Capak P., Ilbert O., Blain A. W., et al. (2011). The Redshift and Nature of AzTEC/COSMOS 1: A Starburst Galaxy at z = 4.6. THE ASTROPHYSICAL JOURNAL LETTERS, 731, 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.
