Submillimeter Emission from Water in the W3 Region

Abstract

We have mapped the submillimeter emission from the 1(10)-1(01) transition of ortho-water in the W3 star-forming region. A 5'x5' map of the W3 IRS4 and W3 IRS5 region reveals strong water lines at half the positions in the map. The relative strength of the Odin lines compared to previous observations by SWAS suggests that we are seeing water emission from an extended region. Across much of the map the lines are double-peaked, with an absorption feature at -39 km/s; however, some positions in the map show a single strong line at -43 km/s. We interpret the double-peaked lines as arising from optically thick, self-absorbed water emission near the W3 IRS5, while the narrower blue-shifted lines originate in emission near W3 IRS4. In this model, the unusual appearance of the spectral lines across the map results from a coincidental agreement in velocity between the emission near W3 IRS4 and the blue peak of the more complex lines near W3 IRS5. The strength of the water lines near W3 IRS4 suggests we may be seeing water emission enhanced in a photon-dominated region.

Accepted to A&A Letters as part of the special Odin issue; 4 pages

References in corpus (2)

• Water Abundance in Molecular Cloud Cores
• Submillimeter Wave Astronomy Satellite Observations of Extended Water Emission in Orion

Cited by in corpus (6)

• Photodesorption of Ices II: H2O and D2O
• Emission of CO, CI, and CII in W3Main
• Odin observations of water in molecular outflows and shocks
• High-resolution SOFIA/EXES Spectroscopy of Water Absorption Lines in the Massive Young Binary W3 IRS 5
• Upper limits to the water abundance in starburst galaxies
• Herschel and Odin observations of H2O, CO, CH, CH+, and NII in the barred spiral galaxy NGC 1365. Bar-induced activity in the outer and inner circumnuclear tori