Description of source "G28.28-0.36" from Towner et al. (2017)


The only 1.3 cm continuum emission detected in this field is strong, resolved emission associated with the well-known core-halo UC H II region G28.288–0.364 (e.g., Kurtz et al. 1994), ∼20″ E–NE of the EGO (Figure 1).

This UC H II region was detected at 3.6 and 1.3 cm by Cyganowski et al. (2011a), who designated it F-CM1. Notably, we do not detect 1.3 cm continuum emission from the Cyganowski et al. (2011a) 3.6 cm source CM1, which is coincident with the EGO and ∼1 2 NE of a 6.7 GHz CH3OH maser (Cyganowski et al. 2009, 2011a). The relatively high rms noise of the new 1.3 cm VLA image for this source (the third highest of our sample; Table 2) means that our 1.3 cm limit is only a factor of ∼1.4 improvement over that of Cyganowski et al. (2011a), and the mismatch in beam size precludes combining the two data sets to better constrain CM1ʼs cm-λ spectral index. Only one 25 GHz CH3OH maser is detected within the VLA FOV; this maser is ~7² north of F-CM1 and is coincident with a 44 GHz CH3OH maser reported by Cyganowski et al. (2009).