Estimating black hole masses in active galaxies

[christinahedges]

Measuring the mass of black holes in active galactic nuclei (AGN) can prove challenging. Understanding the mass of black holes in other galaxies informs our models of galaxy formation in the universe. A recent analysis of the Kepler data of an active galaxy suggests that oscillation frequencies in the Kepler lightcurve of an AGN appear predictive of the central black hole mass (Smith et al. 2018). The K2 mission has observed dozens of active galaxies, including the very bright BL Lac-type object OJ 287. These data have been challenging to use because Keplers instrumental systematics show time-scales which tend to be similar to the oscillation frequencies of AGN (O’Brien et al. 2018). However, improved detrending methods may enable Kepler’s AGN data set to be utilized. For example, PSF photometry may enable a more effective approach towards remove systematics introduced by focus changes and sources drifting out of apertures.