Spectral characteristics of water megamaser galaxies. II. ESO 103-G035, TXS 2226-184, and IC 1481

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.

Based on observations collected at the European Southern Observatory, Chile.