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Letters to Nature

Nature 314, 144-146 (14 March 1985) | doi:10.1038/314144a0; Accepted 28 December 1984

A very bright water vapour maser source in the galaxy NGC3079

Aubrey D. Haschick* & Willem A. Baan†

  1. *Haystack Observatory, Massachusetts Institute of Technology, Westford, Massachusetts 01886, USA
  2. †Arecibo Observatory, Arecibo, Puerto Rico 00612

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The 616–523 transition of water vapour at 22.235080 GHz has been found in our Galaxy to be associated with regions of young star formation1,2. H2O maser emission was detected initially in an external galaxy by Churchwell et al.3. To extend the range of detected properties of 'star burst' galaxies (galaxies showing an enhanced star formation from their optical spectra) we undertook an initial survey for H2O maser emission in this type of galaxy, but with negative results. Here we report on the subsequent extension of this survey to spiral galaxies displaying continuum radio emission, which is also an indication of star formation activity. We have detected the most luminous H2O maser source yet reported, approx500 L0, in the galaxy NGC3079. OH absorption was also detected in this galaxy and we suggest that maser amplification of the nuclear radio source causes the observable H2O emission.

The 30 galaxies for the survey reported here were selected from lists4'5 of bright spiral galaxies containing radio sources having both compact and extended components. The observations were carried out in March, April and May 1984 using the 37-m radio telescope of Haystack Observatory, equipped with a maser receiver and a 1,024 channel digital auto-correlator.