[CII] line emission in BRI1335-0417 at z=4.4
  Using the 12m APEX telescope, we have detected redshifted emission from the
157.74micron [CII] line in the z=4.4074 quasar BRI1335-0417. The linewidth and
redshift are in good agreement with previous observations of high-J CO line
emission. We measure a [CII] line luminosity, L_[CII] = (16.4 +/- 2.6)x10^9
Lsun, making BRI~1335-0417 the most luminous, unlensed [CII] line emitter known
at high-redshift. The [CII]-to-FIR luminosity ratio of (5.3+/-0.8)x10^-4 is ~3x
higher than expected for an average object with a FIR luminosity L_FIR =
3.1x10^13 Lsun, if this ratio were to follow the trend observed in other
FIR-bright galaxies that have been detected in [CII] line emission. These new
data suggest that the scatter in the [CII]-to-FIR luminosity ratio could be
larger than previously expected for high luminosity objects. BR1335-0417 has a
similar FIR luminosity and [CII]/CO luminosity compared to local ULIRGS and
appears to be a gas-rich merger forming stars at a rate of a few thousand solar
masses per year.
