Open AccessAustralia Telescope Compact Array 1.2‐cm observations of the massive star‐forming region G305.2+0.2
Author(s) -
Walsh Andrew J.,
Chapman Jacqueline F.,
Burton Michael G.,
Wardle Mark,
Millar T. J.
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2007.12240.x
Subject(s) - physics , maser , astrophysics , telescope , radio telescope , emission spectrum , line (geometry) , astronomy , star formation , green bank telescope , rotational temperature , core (optical fiber) , stars , spectral line , galaxy , optics , geometry , mathematics
We report on Australia Telescope Compact Array observations of the massive star‐forming region G305.2+0.2 at 1.2 cm. We detected emission in five molecules towards G305A, confirming its hot core nature. We determined a rotational temperature of 26 K for methanol. A non‐local thermodynamic equilibrium excitation calculation suggests a kinematic temperature of the order of 200 K. A time‐dependent chemical model is also used to model the gas‐phase chemistry of the hot core associated with G305A. A comparison with the observations suggest an age of between 2 × 10 4 and 1.5 × 10 5 yr . We also report on a feature to the south‐east of G305A which may show weak Class I methanol maser emission in the line at 24.933 GHz. The more evolved source G305B does not show emission in any of the line tracers, but strong Class I methanol maser emission at 24.933 GHz is found 3 arcsec to the east. Radio continuum emission at 18.496 GHz is detected towards two H ii regions. The implications of the non‐detection of radio continuum emission towards G305A and G305B are also discussed.