Archive abstract

Abstract of the proposal for the experiment ET045A

The elliptical/S0 galaxy TXS2226-184 hosts the first case of water gigamaser, detected 25 years ago. While the association of this luminous maser source is almost surely related to the AGN activity of the galaxy, until now, its origin has not been unveiled. A very recent VLBI study reported by Surcis et al. (A&A, accepted) has, for the first time, associated the water maser features with the most luminous radio continuum nuclear clump and proposed a speculative model for the maser origin. However, despite their thorough analysis, the nature of the maser emission, either related to a nuclear jet/outflow or an accretion disk, remains somewhat enigmatic. This is due mostly because of the lack of VLBI multi-frequency maps of the radio continuum emission in the nucleus of this galaxy. Here, we thus propose to obtain sensitive EVN radio-continuum maps of TXS2226 at L, C, and K bands, in order to gather a clear scenario of the nuclear region by unveling the presence of components ascribable to AGN activity. This will ultimately lead to a first confident and definite answer to the nature of the maser in this galaxy.
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