A systematic observational study of radio properties of H2O megamaser
  Seyfert 2s: A Guide for H2O megamaser surveys
  Analyzing archival data from different telescopes, H2O megamaser Seyfert 2s
appeared to exhibit higher nuclear radio luminosities than non-masing Seyfert
2s (Zhang et al. 2012). This has been confirmed by our follow-up study on
multi-band (11, 6, 3.6, 2, 1.3 cm) radio properties of maser host Seyfert 2s,
through systematic Effelsberg observations (Liu et al. 2017). The nuclear radio
luminosity was supposed to be a suitable indicator to guide future AGN maser
searches. Thus we performed a pilot survey with the Effelsberg telescope on H2O
maser emission toward a small sample of radio-bright Seyfert 2 galaxies with
relatively higher redshift (>0.04). Our pilot survey led to one new megamaser
source and one additional possible detection, which reflects our success in
selecting H2O megamaser candidates compared to previous observations (higher
detection rate, larger distance). Our successful selection technique choosing
Seyfert 2s with radio-bright nuclei may provide good guiding for future H2O
megamaser surveys. Therefore we are conducting a large systematic survey toward
a big Seyfert 2 sample with such radio-bright nuclei. Detections of luminous
H2O masers at large distance (z>0.04) may hold the great potential to increase
our knowledge on the central highly obscured but still very enigmatic regions
of active Seyfert galaxies (Zhang et al. 2017).
