SiO maser emission from AGB stars

Title: Ground Vibrational State SiO Emission in the VLA BAaDE Survey

Authors: Dike, V.; Morris, M. R.; Rich, R. M.; Lewis, M. O.; Quiroga-Nuñez, L. H.; Stroh, M. C.; Trapp, A. C.; Claussen, M. J.

First Author’s Institution: Department of Physics and Astronomy, University of California- Los Angeles

Status: Accepted in Astronomical Journal

ADS: 2020arXiv201209348D

Using a subsample of the Bulge Asymmetries and Dynamical Evolution (BAaDE) survey of stellar SiO masers, we explore the prevalence and characteristics of 28SiO J = 1 − 0, v = 0 emission. We identify 90 detections of maser, thermal, or composite 28SiO J = 1 − 0, v = 0 emission out of approximately 13,000 candidate spectra from the NSF’s Karl G. Jansky Very Large Array (VLA). We find that the detected sources are likely asymptotic giant branch (AGB) stars belonging to a bright, foreground Milky Way stellar disk population.

For the 32 sources showing thermal components, we extract values for outflow velocity by fitting thermal line profiles. We find a range of circumstellar envelope expansion velocities, and compare to previously recorded OH and CO expansion velocities.

This preliminary survey is already the largest study of stellar ground-vibrational-state SiO masers to date, and will be expanded to include the entire VLA BAaDE dataset when data reduction for the 18,988 target sources is completed.