Spectral characteristics of water megamaser galaxies^*

II. ESO 103-G035, TXS 2226-184, and IC 1481

¹ Astronomisches Institut Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany
² Universidad Católica del Norte, Avenida Angamos 0610, Antofagasta, Chile
³ Max–Planck–Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: chenkel@mpifr-bonn.mpg.de

Corresponding author: N. Bennert, nbennert@astro.rub.de

Received: 13 October 2003
Accepted: 25 February 2004

Abstract

Long-slit optical emission-line spectra of the H₂O megamaser galaxies ESO 103-G035, TXS 2226-184, and IC 1481 are evaluated in order to look for characteristics typical for water-megamaser galaxies. We present rotation curves, line ratios, electron densities, temperatures, and Hβ luminosities. The successful line-profile decompositions rest on d-Lorentzians with an additional parameter d to adjust the wings, rather than Gaussians or Lorentzians as basic functions. No significant velocity gradient is found along the major axis in the innermost 2 kpc of TXS 2226-184. IC 1481 reveals a spectrum suggestive of a vigorous starburst in the central kiloparsec 10⁸ years ago. None of the three galaxies shows any hints for outflows nor special features which could give clues to the presence of H₂O megamaser emission. The galaxies are of normal Seyfert-2 (ESO 103-G035) or LINER (TXS 2226-184, IC 1481) type.