Ammonia observations of the nearby molecular cloud MBM 12

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We present NH_3(1,1) and (2,2) observations of MBM 12, the closest known molecular cloud (65-pc distance), aimed at finding evidence for on-going star formation processes, No local temperature (with a T_rot upper limit of 12 K) or linewidth enhancement is found, which suggests that the area of the cloud that we have mapped (∼ 15-arcmin size) is not currently forming stars. Therefore this nearby 'starless' molecular gas region is an ideal laboratory to study the physical conditions preceding new star formation. A radio continuum source has been found in Very Large Array archive data, close to but outside the NH_3 emission. This source is likely to be a background object.
© 2000 RAS. We thank John Ball, Kevin Dudevoir and Phil Shute for their help during the observations at Haystack Observatory. JFG and JMT are supported in part by DGESIC grant PB98-0670-CO2 and by Junta de Andalucía (Spain). SP is supported by DGICYT grant PB96-0610. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Radio astronomy at MIT Haystack Observatory is supported by the US National Science Foundation.
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