ACTIVE STAR-FORMATION TOWARD THE ULTRACOMPACT H-II REGIONS G45.12+0.13 AND G45.07+0.13

A multiwavelength study of the molecular cores containing the ultracom pact (UC) H II regions G45.12+0.13 and G45.07+0.13 reveals a series of phenomenological differences that distinguish the age of these cores in terms of their development of high-mass star formation. First, we r eport the discovery of massive, bipolar molecular outflows from both U C H II regions. The G45.12+0.13 UC H II region lies centered on a spat ially extended, 6 km s(-1) outflow that we have mapped in the CO J = 2 --> 1, 3 --> 2, 6 --> 5, (CO)-C-13 2 --> 1, and (CO)-O-18 2 --> 1 tra nsitions at the Caltech Submillimeter Observatory (CSO). The broad bip olar structure is optically thick in the (CO)-C-12 line. The (CO)-C-13 measurements imply a large outflow mass of 4800 M. (12% of the total cloud mass). Interferometric observations with the Owens Valley Radio Observatory (OVRO) millimeter array in the (CO)-C-13 1 --> 0 line reso lve the gas into at least two outflows, one of which emanates from the 4.0 Jy, 110 GHz source identified with the UC H II region. An additio nal outflow is driven by an adjacent young, embedded object that contr ibutes to the extended submillimeter continuum emission imaged with th e CSO bolometer array camera. Lying in a separate core a few arcminute s away, the G45.07+0.13 UC H II region contains H2O masers and present s higher velocity (11 km s(-1)) yet more compact CO emission. An outfl ow has been detected in the CO 6 --> 5 transition, along with a compac t submillimeter continuum source. OVRO observations in the CS J = 2 -- > 1 transition confirm a compact outflow centered on the 98 GHz contin uum source toward which infall is also seen in the form of redshifted absorption. The multiple outflows, higher CO antenna temperatures, mor e extended submillimeter and radio continuum emission, and lack of H2O masers all distinguish the core containing G45.12+0.13 as a more adva nced site of massive star formation than the neighboring core containi ng G45.07+0.13.