AMMONIA AND CO OUTFLOW AROUND 6.7 GHz METHANOL MASERS

Abstract

Single point observations are presented in NH 3  (1, 1) and (2, 2) inversion transitions using the Effelsberg 100 m telescope for a sample of 100 6.7 GHz methanol masers and mapping observations in the 12 CO and 13 CO (1 − 0) transitions using the Purple Mountain Observatory Delingha 13.7 m telescope for 82 sample sources with detected ammonia. A further 62 sources were selected for either 12 CO or 13 CO line outflow identification, producing 45 outflow candidates, 29 using 12 CO and 16 using 13 CO data. Twenty-two of the outflow candidates were newly identified, and 23 had trigonometric parallax distances. Physical properties were derived from ammonia lines and CO outflow parameters were calculated. Histograms and statistical correlations for ammonia, CO outflow parameters, and 6.7 GHz methanol maser luminosities are also presented. No significant correlation was found between ammonia and maser luminosity. However, weak correlations were found between outflow properties and maser luminosities, which may indicate that outflows are physically associated with 6.7 GHz masers.