CO Observations of a FeLoBAL Quasar with an Hα $\alpha$ Absorption Line at z = 2.3

SDSS J083942.11+380526.3 is an Iron Low-ionization Broad Absorption Line (FeLoBAL) quasar at z = 2:3, and Aoki et al. (2006) recently found the presence of an H absorption line in the broad H emission line. Motivated by an idea that this quasar may be a huge molecular gas reservoir in the early phase of quasar evolution, we made CO(J = 3–2) observations of it using the Nobeyama Millimeter Array. No significant CO emission was detected; although an emission-like feature (2:5 ) was seen close ( 200) to the quasar, we regard it as noise. The obtained 3 upper limit on the CO luminosity is LCO.J=3–2/ = 4:5 10 K km s 1 pc, which corresponds to M.H2/ = 3:6 10Mˇ if we adopt CO-to-H2 conversion factor of 0.8 Mˇ (K km s 1 pc/ . This upper limit is comparable to LCO.J=3–2/ (and thus the molecular gas mass) detected in quasars and BAL quasars at z = 1–3, and no sign of the presence of the huge amount of molecular gas in this FeLoBAL quasar was obtained.