EXPANDED VERY LARGE ARRAY DETECTION OF 44.1 GHz CLASS I METHANOL MASERS IN SAGITTARIUS A

Journal Article · Tue Sep 20 04:00:00 EDT 2011 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/739/1/L21· OSTI ID:21565455

Pihlstroem, Y M ^[1]; Sjouwerman, L O ^[2]

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1. Department of Physics and Astronomy, University of New Mexico, MSC07 4220, Albuquerque, NM 87131 (United States)
2. National Radio Astronomy Observatory, P.O. Box O, 1003 Lopezville Rd., Socorro, NM 87801 (United States)

We report on the detection of 44 GHz Class I methanol (CH{sub 3}OH) maser emission in the Sagittarius A (Sgr A) complex with the Expanded Very Large Array (EVLA). These EVLA observations show that the Sgr A complex harbors at least four different tracers of shocked regions in the radio regime. The 44 GHz masers correlate with the positions and velocities of previously detected 36 GHz CH{sub 3}OH masers, but less with 1720 MHz OH masers. Our detections agree with theoretical predictions that the densities and temperatures conducive for 1720 MHz OH masers may also produce 36 and 44 GHz CH{sub 3}OH maser emission. However, many 44 GHz masers do not overlap with 36 GHz methanol masers, suggesting that 44 GHz masers also arise in regions too hot and too dense for 36 GHz masers to form. This agrees with the non-detection of 1720 MHz OH masers in the same area, which are thought to be excited under even cooler and less dense conditions. We speculate that the geometry of the 36 GHz masers outlines the current location of a shock front.

• OSTI ID: 21565455
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 739; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
79 ASTRONOMY AND ASTROPHYSICS
ALCOHOLS
AMPLIFIERS
COSMIC RADIO SOURCES
DETECTION
ELECTRONIC EQUIPMENT
EQUIPMENT
GALAXIES
HYDROXY COMPOUNDS
MASERS
METHANOL
MICROWAVE AMPLIFIERS
MICROWAVE EQUIPMENT
MILKY WAY
ORGANIC COMPOUNDS