Description of source "G30.54+0.02" from Kim et al. (2019)

G30.54+0.02 shows only redshifted EHV lines at a velocity of 102 km s1 in 2010 (Figure 1). The EHV lines are shifted from the systemic velocity (48.0 km s1) by 54 km s1. The redshifted components disappeared in 2011, and new weak lines appeared between 66 and 33 km s1 and near the systemic velocity. Urquhart et al. (2011) also detected multiple maser lines between 40 and +70 km s1 using the Green Bank 100 m telescope (FWHM=3000) in a similar period (from 2009 Nov 25 to 2010 Dec 10). Hence the blue- and red-shifted EHV components seem to be very variable. There is no previous report about the redshifted EHV components.