Quasi-simultaneous 43 and 86 GHz SiO Maser Observations and Potential Bias in the BAaDE Survey Are Resolved

Abstract

We observed the 43 GHz v=1, 2, and 3 and 86 GHz v=1 SiO maser transitions quasi-simultaneously for a Mira-variable-dominated sample of over 80 sources from the Bulge Asymmetries and Dynamical Evolution (BAaDE) project, using ATCA, and statistically compared the relative line strengths. On average, the 43 GHz v=1 line is brighter than the 86 GHz v=1 line by a factor of 1.36+/-0.15. As a result, an 86 GHz v=1 observed sample can be observed to 85.9% of the distance of a 43 GHz v=1 observed sample using the same sensitivity. We discuss what impact this may have on the BAaDE Galactic plane survey using the VLA and ALMA. Despite fewer v=3 detections, specific trends are discerned or strengthened when the 43 GHz v=3 line is detected. In particular the 43 and 86 GHz v=1 lines are on average equal for sources with no detectable 43 GHz v=3 emission, but the 43 GHz v=1 line strength is on average about twice as bright as the 86 GHz v=1 line for sources with detectable 43 GHz v=3 emission. Some weak correlations are found between line strengths and Midcourse Space Experiment flux densities and colors, which are tightened when considering only sources with detectable 43 GHz v=3 emission. We discuss these trends in the context of a radiative pumping model to highlight how the 43 GHz v=3 line, when coupled with the v=1 and v=2 lines, can further our understanding of variable conditions like density in the circumstellar envelopes.

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Cited by in corpus (9)

• Radio Stars: from kHz to THz
• Accurate OH Maser Positions From The SPLASH Survey III: The Final 96 Square Degrees
• The Bulge Asymmetries and Dynamical Evolution (BAaDE) SiO Maser Survey at 86 GHz with ALMA
• Carbon- and Oxygen-rich Asymptotic Giant Branch (AGB) stars in the Bulge Asymmetries and Dynamical Evolution (BAaDE) survey
• Ground Vibrational State SiO Emission in the VLA BAaDE Survey
• Infrared color separation between thin-shelled oxygen-rich and carbon-rich AGB stars
• Long-period maser-bearing Miras in the Galactic center: period-luminosity relations and extinction estimates
• Long-term Simultaneous Monitoring Observations of SiO and H2O Masers toward the Mira Variable WX Serpentis
• 86 GHz SiO masers in Galactic Centre OH/IR stars