2012/09/28 by Thomas K. T. Fok, Jun‐ichi Nakashima, Jun-ichi Nakashima +3 · 5 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.1088/0004-637x/760/1/65
52 pages, 11 figures, 15 tables; accepted for publication in ApJ; full resolution version is available from http://web.hku.hk/~junichi/paper/fok_etal_atca-Wd1.pdf
arxiv created 2012/09/28 · openalex publication_date 2012/11/05 · arxiv updated 2015/06/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We report the results of Australia Telescope Compact Array (ATCA) observations of the Westerlund~1 (Wd1) region in the SiO v=1, J=1-0 and H2O 6(16)-5(23) maser lines, and we also report the analysis of maser properties of red supergiants (RSGs) associated with 6 massive clusters including Wd1. The primary purpose of this research is to explore possibilities of using maser emission for investigating the nature of massive clusters and associated RSGs. The SiO v=1, J=1-0 and H2O 6(16)-5(23) maser lines are detected toward 2 of 4 known RSGs in Wd1. The large velocity ranges of maser emission are consistent with the RSG status. RSGs with maser emission tend to exhibit redder log (F21/F12) and [K-12.13] colors compared to RSGs with no maser emission. The mass-loss rates derived from dust radiative transfer modeling suggest that RSGs with maser emission tend to exhibit larger mass-loss rates compared to RSGs with no maser emission. In an extended sample of 57 RSGs in 6 massive clusters, detections in the SiO line tend to homogeneously distribute in absolute luminosity L, whereas those in the H2O line tend to distribute in a region with large L values.