Detection of Atomic Carbon [C II] 158 μm and Dust Emission from a z = 7.1 Quasar Host Galaxy
Abstract
Using the IRAM Plateau de Bure Interferometer, we report the detection of the 158 μm [C II] emission line and underlying dust continuum in the host galaxy of the quasar ULAS J112001.48+064124.3 (hereafter J1120+0641) at z = 7.0842 ± 0.0004. This is the highest redshift detection of the [C II] line to date, and allows us to put the first constraints on the physical properties of the host galaxy of J1120+0641. The [C II] line luminosity is 1.2 ± 0.2 × 109 L ⊙, which is a factor ~4 lower than observed in a luminous quasar at z = 6.42 (SDSS J1148+5251). The underlying far-infrared (FIR) continuum has a flux density of 0.61 ± 0.16 mJy, similar to the average flux density of z ~ 6 quasars that were not individually detected in the rest-frame FIR. Assuming that the FIR luminosity of L FIR = 5.8 × 1011-1.8 × 1012 L ⊙ is mainly powered by star formation, we derive a star formation rate in the range 160-440 M ⊙ yr-1 and a total dust mass in the host galaxy of 6.7 × 107-5.7 × 108 M ⊙ (both numbers have significant uncertainties given the unknown nature of dust at these redshifts). The [C II] line width of σ V = 100 ± 15 km s-1 is among the smallest observed when compared to the molecular line widths detected in z ~ 6 quasars. Both the [C II] and dust continuum emission are spatially unresolved at the current angular resolution of 2.0 × 1.7 arcsec2 (corresponding to 10 × 9 kpc2 at the redshift of J1120+0641).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- June 2012
- DOI:
- 10.1088/2041-8205/751/2/L25
- arXiv:
- arXiv:1203.5844
- Bibcode:
- 2012ApJ...751L..25V
- Keywords:
-
- cosmology: observations;
- galaxies: active;
- galaxies: high-redshift;
- galaxies: individual: ULAS J112001.48+064124.3;
- galaxies: ISM;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 7 pages, 3 figures. Published in ApJ Letters