86-GHz SiO masers in Galactic centre OH/IR stars. (11th June 2020)

• Record Type: Journal Article
• Authors: Messineo, Maria; Sjouwerman, Lorant O; Habing, Harm J; Omont, Alain
• Is Part Of: Publications of the Astronomical Society of Japan. Volume 72:Number 4(2020:Aug.)
• Publication Date: 2020-06-11
• Subjects: circumstellar matter -- Galaxy: stellar content -- infrared: stars -- masers -- stars: late-type; Astronomy -- Periodicals; 520.5
• DOI: 10.1093/pasj/psaa040
• Languages: English
• ISSNs: 0004-6264

Abstract

Abstract: We present results on a search for 86.243-GHz SiO ( J = 2→1, $v$ = 1) maser emission toward 67 OH/IR stars located near the Galactic centre. We detected 32 spectral peaks, of which 28 correspond to SiO maser lines arising from the envelopes of these OH/IR stars. In OH/IR stars, we obtained an SiO maser detection rate of about $40\%$ . We serendipitously detected two other lines from OH/IR stars at ≈86.18 GHz, which could be due to a CCS-molecule transition at 86.181 GHz or probably to an highly excited OH molecular transition at 86.178 GHz. The detection rate of 86-GHz maser emission is found to be about $60\%$ for sources with the Midcourse Space Experiment (MSX) A − E < 2.5 mag; but it drops to $25\%$ for the reddest OH/IR stars with MSX A − E > 2.5 mag. This supports the hypothesis by Messineo (2002, A&A, 393, 115) that the SiO masers are primarily found in relatively thinner circumstellar material.