The Mass of the Black Hole in the Seyfert 1 Galaxy NGC 4593 from Reverberation Mapping

Abstract

We present new observations leading to an improved black hole mass estimate for the Seyfert 1 galaxy NGC 4593 as part of a reverberation-mapping campaign conducted at the MDM Observatory. Cross-correlation analysis of the Hβ emission-line light curve with the optical continuum light curve reveals an emission-line time delay of τcent=3.73+/-0.75 days. By combining this time delay with the Hβ line width, we derive a central black hole mass of MBH=(9.8+/-2.1)×106 Msolar, an improvement in precision of a factor of several over past results.