We present the results of a recent reverberation mapping campaign for UGC 06728, a nearby low-luminosity Seyfert 1 in a late-type galaxy. Nightly monitoring in the spring of 2015 allowed us to determine an H$beta$ time delay of $tau = 1.4 pm 0.8$ days. Combined with the width of the variable H$beta$ line profile, we determine a black hole mass of $M_{rm BH} = (7.1 pm 4.0) times 10^5$ M$_{odot}$. We also constrain the bulge stellar velocity dispersion from higher-resolution long slit spectroscopy along the galaxy minor axis and find $sigma_{star} = 51.6 pm 4.9$ km s$^{-1}$. The measurements presented here are in good agreement with both the $R_{rm BLR} - L$ relationship and the $M_{rm BH}-sigma_{star}$ relationship for AGNs. Combined with a previously published spin measurement, our mass determination for UGC 06728 makes it the lowest-mass black hole that has been fully characterized, and thus an important object to help anchor the low-mass end of black hole evolutionary models.
تحميل البحث