A systematic observational study of radio properties of H2O megamaser Seyfert-2 galaxies

Abstract

A systematic study is performed on radio properties of H${}_2$O megamaser host Seyfert 2 galaxies, through multi-band radio continuum observations (at 11cm, 6.0 cm, 3.6 cm, 2.0 cm and 1.3 cm) with the Effelsberg 100-m radio telescope within a total time duration of four days. For comparison, a control Seyfert 2 galaxy sample without detected maser emission was also observed. Spectral indices were determined for those sources for which measurements exist at two adjacent bands assuming a power-law dependence S${}_{\nu }\propto {\nu }^{-\alpha }$, where S is the flux density and $\nu$ is the frequency. Comparisons of the radio continuum properties between megamaser and non-masing Seyfert 2s show no difference in spectral indices. However, a difference in radio luminosity is statistically significant, i.e. the maser galaxies tend to have higher radio luminosities by a factor of 2 to 3 than the non-masing ones, commonly reaching values above a critical threshold of 10${}^{29}$ ergs${}^{-1}$Hz${}^{-1}$. This result confirms an earlier conclusion by Zhang et al. (2012), but is based on superior data with respect to the time interval within which the data were obtained, with respect to the observational facility (only one telescope used), the number of frequency bands.

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Cited by in corpus (5)

• Quantifying Feedback from Narrow Line Region Outflows in Nearby Active Galaxies. III. Results for the Seyfert 2 Galaxies Markarian 3, Markarian 78, and NGC 1068
• Water megamaser emission in hard X-ray selected AGN
• A More Efficient Search for H2O Megamaser Galaxies : The Power of the X-ray and Mid-infrared Photometry
• Water megamaser and central black hole masses in a large sample of galaxies
• Tracing circumnuclear dense gas in H2O maser galaxies