Water vapor maser emission in the 6 _ { 16 } –5 _ { 23 } transition towards the narrow-line Seyfert 1 ( NLS1 ) galaxy NGC 4051 has been discovered during an ongoing single-dish extragalactic water maser survey .
The Doppler-shifted maser components appear to bracket maser components lying near the systemic velocity of the galaxy symmetrically .
The tentative result of a Very Large Array ( VLA ) snapshot observation is that the masers are confined within 0.1 arcsec ( 5 pc at a distance D = 9.7 Mpc ) of the radio continuum peak seen at 8.4 GHz .
The low luminosity of the maser ( \sim 2 L _ { \sun } ) is not typical for masers that coincide with the radio continuum nucleus and appear associated with Active Galactic Nucleus ( AGN ) activity .
A low-luminosity maser in a Type 1 Seyfert nucleus could be explained by a low maser gain resulting from the lower inclination of an obscuring disk around an active nucleus .