SUBMILLIMETER OBSERVATIONS OF CO IN THE W3 CORE

We present observations of CO J = 3-2 and J = 6-5 emission from the W3 IRS 5-IRS 4 region. A high-sensitivity spectrum in CO J = 3-2 at IRS 5 shows extremely high velocity gas with a total velocity width of 200 km s-1. The CO J = 3-2 map shows the presence of compact blueshifted and redshifted lobes centered on IRS 5. Both lobes have diameters at h alf-maximum of about 8''. Spectra in CO and ''CO J = 3-2 toward IRS 4 have red and blue pedestal features, indicating moving gas associated with IRS 4. The new observations are combined with our previous data i n CO and (CO)-C-13 J = 2-1 lines to determine the gas temperature of t he wing components associated with IRS 5 and IRS 4. The gas temperatur e for the red and blue outer (or ''CO emission-free) wings in IRS 5 is similar at 60 K. The gas temperature is 76 K for the red inner wing a nd is 38 K for the blue inner wing. The blueshifted gas toward IRS 4 h as an average gas temperature of 49 K, although there is a systematic increase in gas temperature with velocity, the temperature reaching to 160 K. For the outer red pedestal part in IRS 4, the gas temperature is at least 45 K. The excitation temperature for the widespread -38 km s-1 absorption feature in CO J = 2-1 and J = 3-2 spectra is about 24 K at the IRS 5 position, and is about 16 K at the IRS 4 position. The excitation temperatures and velocities from submillimeter CO observati ons are compared with those independently found from IR observations o f CO in absorption. We suggest that the -38 km s-1 absorption componen t in the submillimeter CO spectra at IRS 5 corresponds to the cold com ponent with N(CO) = 1.1 X 10(19) cm-2 found from the infrared CO spect ra of IRS 5. The blue outer wing (V(LSR) = -105 to -50 km s-1) in the CO J = 3-2 spectra at IRS 5 probably corresponds to the blueshifted ab sorption component found in the IR CO spectrum of IRS 5.