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Discovery of a luminous water megamaser in the FRII radiogalaxy 3C403

A. Tarchi·C. Henkel·M. Chiaberge·K. M. Menten
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Abstract

We report the first detection of a water megamaser in a radio-loud galaxy, 3C403. This object has been observed as part of a small sample of FRIIs with evidence of nuclear obscuration. The isotropic luminosity of the maser is ~1200 L(sun). With a recessional velocity of cz ~ 17680 km/s it is the most distant water maser so far reported. The line arises from the densest interstellar gas component ever observed in a radio-loud galaxy. Two spectral features are observed, likely bracketing the systemic velocity of the galaxy. These may either arise from the tangentially seen parts of a nuclear accretion disk or from dense warm gas interacting with the radio jets.

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A. Tarchi, C. Henkel, M. Chiaberge, K. M. Menten. 2003-07-03. Discovery of a luminous water megamaser in the FRII radiogalaxy 3C403. https://doi.org/10.1051/0004-6361%3A20031062

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