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Megamasers in Young Active Galactic Nuclei

Published online by Cambridge University Press:  07 August 2017

Willem A. Baan
Willem A. Baan*
Affiliation:
Arecibo Observatory, Arecibo, P.R. 00613

Extract

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Megamaser emission provides new insights into the physics of active galactic nuclei. The megamaser phenomenon is consistent with a low-gain amplification model, where inverted foreground molecules amplify the radio continuum from the nucleus. The molecular gas seen in emission in the megamaser galaxies is located between 50 and 300 parsecs from the nucleus covering part of a possible NLR. Megamasers have been found for the molecules OH, H2CO and H2O. However, only OH megamasers form a clearly identifiable group of galaxies. They occur in prominent FIR galaxies and the FIR radiation field serves as a pumping agent for the OH molecules (Baan 1988). As a result only the ground state lines of OH are in emission, while the lines from excited states are in absorption (see Henkel, Güsten and Baan 1987).

Type
Part 7: Dust, Molecules, Infrared and MM Radiation
Information
Symposium - International Astronomical Union , Volume 134: Active Galactic Nuclei , 1989 , pp. 402 - 403
Copyright
Copyright © Kluwer 1989 

References

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