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Title: ABUNDANT CH{sub 3}OH MASERS BUT NO NEW EVIDENCE FOR STAR FORMATION IN GCM0.253+0.016

Abstract

We present new observations of the quiescent giant molecular cloud GCM0.253+0.016 in the Galactic center, using the upgraded Karl G. Jansky Very Large Array. Observations were made at wavelengths near 1 cm, at the K (24–26 GHz) and Ka (27 and 36 GHz) bands, with velocity resolutions of 1–3 km s{sup −1} and spatial resolutions of ∼0.1 pc, at the assumed 8.4 kpc distance of this cloud. The continuum observations of this cloud are the most sensitive yet made, and reveal previously undetected emission which we attribute primarily to free–free emission from external ionization of the cloud. In addition to the sensitive continuum map, we produce maps of 12 molecular lines: 8 transitions of NH{sub 3}–(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7), and (9, 9), as well as the HC{sub 3}N (3–2) and (4–3) lines, and CH{sub 3}OH 4{sub −1}–3{sub 0}, the latter of which is known to be a collisionally excited maser. We identify 148 CH{sub 3}OH 4{sub −1}–3{sub 0} (36.2 GHz) sources, of which 68 have brightness temperatures in excess of the highest temperature measured for this cloud (400 K) and can be confirmed to be masers. The majority of thesemore » masers are concentrated in the southernmost part of the cloud. We find that neither these masers nor the continuum emission in this cloud provide strong evidence for ongoing star formation in excess of that previously inferred by the presence of an H{sub 2}O maser.« less

Authors:
;  [1]; ; ; ;  [2];  [3]
  1. National Radio Astronomy Observatory, 1003 Lopezville Rd, Socorro, NM 87801 (United States)
  2. Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52245 (United States)
  3. Department of Physics and Astronomy, University of California, 430 Portola Plaza, Box 951547 Los Angeles, CA 90095-1547 (United States)
Publication Date:
OSTI Identifier:
22522393
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 805; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMMONIA; BRIGHTNESS; CLOUDS; GHZ RANGE; MASERS; METHANOL; MILKY WAY; NITRIC OXIDE; NITRILES; SPATIAL RESOLUTION; STAR EVOLUTION; STARS

Citation Formats

Mills, E. A. C., Ott, J., Butterfield, N., Ludovici, D. A., Lang, C. C., Schmitz, S., and Morris, M. R., E-mail: bmills@aoc.nrao.edu. ABUNDANT CH{sub 3}OH MASERS BUT NO NEW EVIDENCE FOR STAR FORMATION IN GCM0.253+0.016. United States: N. p., 2015. Web. doi:10.1088/0004-637X/805/1/72.
Mills, E. A. C., Ott, J., Butterfield, N., Ludovici, D. A., Lang, C. C., Schmitz, S., & Morris, M. R., E-mail: bmills@aoc.nrao.edu. ABUNDANT CH{sub 3}OH MASERS BUT NO NEW EVIDENCE FOR STAR FORMATION IN GCM0.253+0.016. United States. doi:10.1088/0004-637X/805/1/72.
Mills, E. A. C., Ott, J., Butterfield, N., Ludovici, D. A., Lang, C. C., Schmitz, S., and Morris, M. R., E-mail: bmills@aoc.nrao.edu. Wed . "ABUNDANT CH{sub 3}OH MASERS BUT NO NEW EVIDENCE FOR STAR FORMATION IN GCM0.253+0.016". United States. doi:10.1088/0004-637X/805/1/72.
@article{osti_22522393,
title = {ABUNDANT CH{sub 3}OH MASERS BUT NO NEW EVIDENCE FOR STAR FORMATION IN GCM0.253+0.016},
author = {Mills, E. A. C. and Ott, J. and Butterfield, N. and Ludovici, D. A. and Lang, C. C. and Schmitz, S. and Morris, M. R., E-mail: bmills@aoc.nrao.edu},
abstractNote = {We present new observations of the quiescent giant molecular cloud GCM0.253+0.016 in the Galactic center, using the upgraded Karl G. Jansky Very Large Array. Observations were made at wavelengths near 1 cm, at the K (24–26 GHz) and Ka (27 and 36 GHz) bands, with velocity resolutions of 1–3 km s{sup −1} and spatial resolutions of ∼0.1 pc, at the assumed 8.4 kpc distance of this cloud. The continuum observations of this cloud are the most sensitive yet made, and reveal previously undetected emission which we attribute primarily to free–free emission from external ionization of the cloud. In addition to the sensitive continuum map, we produce maps of 12 molecular lines: 8 transitions of NH{sub 3}–(1, 1), (2, 2), (3, 3), (4, 4), (5, 5), (6, 6), (7, 7), and (9, 9), as well as the HC{sub 3}N (3–2) and (4–3) lines, and CH{sub 3}OH 4{sub −1}–3{sub 0}, the latter of which is known to be a collisionally excited maser. We identify 148 CH{sub 3}OH 4{sub −1}–3{sub 0} (36.2 GHz) sources, of which 68 have brightness temperatures in excess of the highest temperature measured for this cloud (400 K) and can be confirmed to be masers. The majority of these masers are concentrated in the southernmost part of the cloud. We find that neither these masers nor the continuum emission in this cloud provide strong evidence for ongoing star formation in excess of that previously inferred by the presence of an H{sub 2}O maser.},
doi = {10.1088/0004-637X/805/1/72},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 805,
place = {United States},
year = {2015},
month = {5}
}