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

Abstract

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.

Authors:
 [1];  [2];  [3]
  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)
  3. MIT Haystack Observatory, Route 40, Westford, MA 01886 (United States)
Publication Date:
OSTI Identifier:
21565455
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal Letters
Additional Journal Information:
Journal Volume: 739; Journal Issue: 1; Other Information: DOI: 10.1088/2041-8205/739/1/L21; Journal ID: ISSN 2041-8205
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC RADIO SOURCES; DETECTION; MASERS; METHANOL; MILKY WAY; ALCOHOLS; AMPLIFIERS; ELECTRONIC EQUIPMENT; EQUIPMENT; GALAXIES; HYDROXY COMPOUNDS; MICROWAVE AMPLIFIERS; MICROWAVE EQUIPMENT; ORGANIC COMPOUNDS

Citation Formats

Pihlstroem, Y. M., Sjouwerman, L. O., and Fish, V. L., E-mail: ylva@unm.edu. EXPANDED VERY LARGE ARRAY DETECTION OF 44.1 GHz CLASS I METHANOL MASERS IN SAGITTARIUS A. United States: N. p., 2011. Web. doi:10.1088/2041-8205/739/1/L21.
Pihlstroem, Y. M., Sjouwerman, L. O., & Fish, V. L., E-mail: ylva@unm.edu. EXPANDED VERY LARGE ARRAY DETECTION OF 44.1 GHz CLASS I METHANOL MASERS IN SAGITTARIUS A. United States. doi:10.1088/2041-8205/739/1/L21.
Pihlstroem, Y. M., Sjouwerman, L. O., and Fish, V. L., E-mail: ylva@unm.edu. Tue . "EXPANDED VERY LARGE ARRAY DETECTION OF 44.1 GHz CLASS I METHANOL MASERS IN SAGITTARIUS A". United States. doi:10.1088/2041-8205/739/1/L21.
@article{osti_21565455,
title = {EXPANDED VERY LARGE ARRAY DETECTION OF 44.1 GHz CLASS I METHANOL MASERS IN SAGITTARIUS A},
author = {Pihlstroem, Y. M. and Sjouwerman, L. O. and Fish, V. L., E-mail: ylva@unm.edu},
abstractNote = {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.},
doi = {10.1088/2041-8205/739/1/L21},
journal = {Astrophysical Journal Letters},
issn = {2041-8205},
number = 1,
volume = 739,
place = {United States},
year = {2011},
month = {9}
}