Extremely Red Submillimeter Galaxies: New z ≳ 4-6 Candidates Discovered using ALMA and Jansky VLA
Abstract
We present the detailed characterization of two extremely red submillimeter galaxies (SMGs), ASXDF1100.053.1 and 231.1, with the Atacama Large Millimeter/submillimeter Array (ALMA) and the Jansky Very Large Array. These SMGs were originally selected using AzTEC at 1100 μm, and are observed by Herschel to be faint at 100-500 μm. Their (sub)millimeter colors are as red as—or redder—than known z ≳ 5 SMGs; indeed, ASXDF1100.053.1 is redder than HFLS 3, which lies at z = 6.3. They are also faint and red in the near-/mid-infrared: ∼1 μJy at IRAC 4.5 μm and <0.2 μJy in the K s filter. These SMGs are also faint in the radio waveband, where F 6GHz = 4.5 μJy for ASXDF1100.053.1 and F 1.4GHz = 28 μJy for ASXDF1100.231.1, suggestive of z={6.5}-1.1+1.4 and z={4.1}-0.7+0.6 for ASXDF1100.053.1 and 231.1, respectively. ASXDF1100.231.1 has a flux excess in the 3.6 μm filter, probably due to Hα emission at z = 4-5. Derived properties of ASXDF1100.053.1 for z = 5.5-7.5 and 231.1 for z = 3.5-5.5 are as follows: their infrared luminosities are [6.5 - 7.4] × 1012 and [4.2-4.5] × 1012 L ⊙ their stellar masses are [0.9-2] × 1011 and [0.4-3] × 1010 M ⊙ their circularized half-light radii in the ALMA maps are ∼1 and ≲0.2 kpc (∼2-3 kpc for 90% of the total flux). Last, their surface infrared luminosity densities, ΣIR, are ∼1 × 1012 and ≳1.5 × 1013 L ⊙ kpc-2, similar to values seen for local (U)LIRGs. These data suggest that ASXDF1100.053.1 and 231.1 are compact SMGs at z ≳ 4 and can plausibly evolve into z ≳ 3 compact quiescent galaxies.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2017
- DOI:
- 10.3847/1538-4357/835/2/286
- arXiv:
- arXiv:1701.01448
- Bibcode:
- 2017ApJ...835..286I
- Keywords:
-
- galaxies: evolution;
- galaxies: formation;
- galaxies: high-redshift;
- submillimeter: galaxies;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 16 pages, 14 figures, accepted to the Astrophysical Journal part1