|
Hafner et al. describe the Maser Monitoring Parkes Project (M2P2),
an ongoing prograsm to observe masers towards high-mass star-forming
regions (HMSFRs) using Murriyang, the CSIRO Parkes radio telescope.
In a first paper, they outline the project and introduce total
intensity (Stokes-I) data from the first two years of observations.
Observations are made of the hydroxyl "main lines" (rest frequencies
at 1665.402 and 1667.359 MHz) and the two "satellite lines" (at
1612.231 and 1720.530 MHz). Their initial identification of individual
maser features across the 63 sources targeted at the 4 transitions
resulted in a total of 1,514 individual maser features. Main-line
masers dominate, as expected since the source selection targeted
HMSFRs. Of the 63 HMSFRs, all have maser features in at least one OH
transition, and 23 have maser features in all four OH transitions.
The image above is a Venn diagram showing the overlap of occurrence of
maser features. The team found that 14.4% of these (203) towards 27
sightlines show significant variability. Variable masers provide a
unique laboratory for the modelling of local environmental conditions
of HMSFRs, and follow-up publications will delve into this in more
detail.
|
