Mosaiced HCO$^{+}$ Observations of W 43 with the BIMA array
Session 35 -- Hat Creek
Display presentation, Tuesday, 9:30-6:30, Pauley Room

## [35.04] Mosaiced HCO$^{+}$ Observations of W 43 with the BIMA array

Niranjan Thatte (U. C. Berkeley), Wm. J. Welch (U. C. Berkeley)

We present maps of the 3 millimeter continuum and the J=1$\rightarrow$0 transition of HCO$^{+}$ toward the massive star forming complex W 43. The composite images were formed by mosaicing 3 fields of the BIMA interferometer. Data from the 12 meter NRAO telescope provided the low spatial frequency information not accessible to the interferometer. We discuss the mosaicing process, with special attention to recovering large scale structure.

The source exhibits a very complex morphology. The continuum emission is extended with respect to the primary beam (2\'{ } FWHM) of the BIMA array, which corresponds to a physical size of several parsecs. The 6\H{ } resolution images show at least 7 distinct continuum peaks. The HCO$^{+}$ emission is also very extended, with several compact components separated in velocity. The line emission exhibits a velocity spread of 20 km/s, with a large asymmetric red shifted wing. We also discuss model geometries for the structure of this complex region.