Copious Amounts of Dust and Gas in a z=7.5 Quasar Host Galaxy
  We present IRAM/NOEMA and JVLA observations of the quasar J1342+0928 at
z=7.54 and report detections of copious amounts of dust and [CII] emission in
the interstellar medium (ISM) of its host galaxy. At this redshift, the age of
the universe is 690 Myr, about 10% younger than the redshift of the previous
quasar record holder. Yet, the ISM of this new quasar host galaxy is
significantly enriched by metals, as evidenced by the detection of the [CII]
158micron cooling line and the underlying far-infrared (FIR) dust continuum
emission. To the first order, the FIR properties of this quasar host are
similar to those found at a slightly lower redshift (z~6), making this source
by far the FIR-brightest galaxy known at z>7.5. The [CII] emission is spatially
unresolved, with an upper limit on the diameter of 7 kpc. Together with the
measured FWHM of the [CII] line, this yields a dynamical mass of the host of
<1.5x10^11 M_sun. Using standard assumptions about the dust temperature and
emissivity, the NOEMA measurements give a dust mass of (0.6-4.3)x10^8 M_sun.
The brightness of the [CII] luminosity, together with the high dust mass, imply
active ongoing star formation in the quasar host. Using [CII]-SFR scaling
relations, we derive star formation rates of 85-545 M_sun/yr in the host,
consistent with the values derived from the dust continuum. Indeed, an episode
of such past high star formation is needed to explain the presence of ~10^8
M_sun of dust implied by the observations.
