Abstract
We report the detection of CO (1 - 0) and CO(3 - 2) emission observed toward the quasar PC 1643+4631A at a redshift corresponding to the z = 3.137 damped Lyα system previously identified in the optical spectrum of the object. This is the highest redshift CO detection reported to date. The CO emission lines have a velocity width ~> 700 km s^-1^ (FWZI). The CO line luminosities are approximately 108 L_sun_, and the mass of molecular gas is approximately 10^12^ M_sun_. Radiative transfer calculations using a large velocity gradient model imply a gas kinetic temperature of ~30 K. The models and observations together indicate that the angular size of the higher excitation CO(3 - 2) emission region is approximately 0.3-0.5 times that of the lower excitation CO(1 - 0) emission region; that is, the gas is appreciably clumped.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
