Spectral survey of a Hot core with an Eruptive Accretion in S255IR NIRS3
(SHEA): The discovery of class I and class II millimeter methanol maser
transitions
We report the detection of the millimeter CH3OH masers including a new
detection of class I (110,11-101,10A) and class II
(61,5-52,4E) maser transitions toward the high-mass protostar S255IR
NIRS3 in post-burst phase. The CH3OH emissions were detected as a mixture of
maser and thermal characteristics. We examine the detected transitions using an
excitation diagram and LTE model spectra and compare the observed properties
with those of thermal lines. Class II CH3OH maser transitions showed
distinctive intensity and velocity distributions from those of thermal
transitions. Bright distinct emission components in addition to the fragmented
and arc-shaped emissions are only detected in class I CH3OH maser
transitions toward southern and western directions from the protostellar
position, implying the presence of the slow outflow shocks.Comment: 9 pages, 4 Figures, 1 Table, Accepted for publication in ApJ