Molecular emission at high redshift: Observations of BR1202-0725

We present recent results for CO(2-1) and 8 GHz continuum observations of one of the most distant quasars known BR1202-0725 (z = 4.7) with the VLA and the NRO 45m telescope. The obtained CO(2-1) intensity was used to estimate the molecular gas properties and mass together with CO(5-4), CO(4-3), and CO(7-6) successfully detected with the Nobeyama Millimeter Array and the IRAM interferometer. It is found that the molecular gas properties in BR1302-0725 are very similar to those in the prototypical starburst galaxy M82; the gas density is n(H-2) similar to 10(4-5) cm(-3); the temperature is as high as 50 - 100 K, and M(H-2) was estimated to be 10(11) M. from the comparison of CO(5-4) luminosity with that in M82 (LCO(5-4) is about 1000 times larger than LCO(5-4) in M82). The 8.4 GHz continuum emission (rest frequency = 48 GHz) was marginally detected. The luminosity (L-nu) ratios to M82, R-BR/82(nu(rest) = 48 GHz), R-BR/M82(lambda(rest) = 100 mu m) were also in the range of 500 - 1000. It is suggested that an intense initial starburst occurs in BR1202-0725 with SFR of 10(3) M. yr(-1), and in this sense BR1202-0725 would be a forming elliptical galaxy.