Misc,
Detection of atomic carbon CII 158 micron and dust emission from a z=7.1 quasar host galaxy
(2012)cite arxiv:1203.5844Comment: 6 pages, 3 figures. Submitted to ApJ Letters.
Abstract
Using the IRAM Plateau de Bure Interferometer, we report the detection of the
158 micron CII 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 CII line to
date, and allows us to put first constraints on the physical properties of the
host galaxy. The CII line luminosity is (1.2+/-0.2)x10^9 Lsun, which is a
factor ~4 lower than observed in a luminous quasar at z=6.42 (SDSS J1148+5251).
The underlying far-infrared 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 at similar frequencies. The far-infrared continuum detection implies a
star-formation rate in the range 160-440 Msun/yr and a total dust mass in the
host galaxy of (9+/-2)x10^7 Msun (both numbers have significant uncertainties
given the unknown nature of dust at these redshifts). The CII line width of
sigma_V=100+/-15 km/s is among the smallest observed when compared to the
molecular line widths detected in z~6 quasars. Both the CII and dust
continuum emission are spatially unresolved at the current angular resolution
of 2.0x1.7 arcsec^2 (corresponding to 10x9 kpc^2 at the redshift of
J1120+0641). The dynamical mass of the host implied by the observed line width
is Mdyn < 1.4x10^11 Msun. If the bulge mass was close to the dynamical mass,
then the black hole-bulge mass ratio is >10 times higher than observed locally.
