REVERBERATION MAPPING OF THEKEPLERFIELD AGN KA1858+4850

Abstract

KA1858+4850 is a narrow-line Seyfert 1 galaxy at redshift 0.078 and is among the brightest active galaxies monitored by the Kepler mission. We have carried out a reverberation mapping campaign designed to measure the broad-line region size and estimate the mass of the black hole in this galaxy. We obtained 74 epochs of spectroscopic data using the Kast Spectrograph at the Lick 3-m telescope from February to November of 2012, and obtained complementary V -band images from five other ground-based telescopes. We measured the Hβ light curve lag with respect to the V -band continuum light curve using both cross-correlation techniques (CCF) and continuum light curve variability modeling with the JAVELIN method, and found rest-frame lags of τ CCF = 13.53 +2.03 −2.32 days and τ JAVELIN = 13.15 +1.08 −1.00 days. The Hβ root-mean-square line profile has a width of σ line = 770 ± 49 km s −1 . Combining these two results and assuming a virial scale factor of f = 5.13, we obtained a virial estimate of M BH = 8.06 +1.59 −1.72 × 10 6 M ⊙ for the mass of the central black hole and an Eddington ratio of L/L Edd ≈ 0.2. We also obtained consistent but slightly shorter emission-line lags with respect to the Kepler light curve. Thanks to the Kepler mission, the light curve of KA1858+4850 has among the highest cadences and signal-to-noise ratios ever measured for an active galactic nucleus; thus, our black hole mass measurement will serve as a reference point for relations between black hole mass and continuum variability characteristics in active galactic nuclei.

Simultaneous Kepler/K2 and XMM-Newton observations of superflares in the Pleiades

“…Thanks to its superb photometric precision in the 420-900 nm band pass, the mission has not only allowed us to identify hundreds of confirmed and thousands of candidate exoplanets, but has also provided an inestimable collection of light curves of stars across most of the Hertzsprung-Russell diagram. It is therefore not surprising that Kepler data has a huge impact not only on exoplanetary science, but also on several other fields of astronomy, such as asteroseismology (Chaplin et al 2010), variability of low mass stars (e.g., McQuillan et al 2014), eclipsing binaries (Prša et al 2011), flares and superflares (Maehara et al 2012;Davenport 2016), and even variability in active galactic nuclei (Pei et al 2014).…”

Stability of the Broad-line Region Geometry and Dynamics in Arp 151 Over Seven Years

“…We also restricted our analysis to the highest-quality data from each campaign, including Tenagra Observatory (2008), WMO (2011), andLCOGT (2015). Photometry measurements were made using the automated aperture photometry code described by Pei et al (2014). The V-band light curve mean values are 15.5, 15.5, and 15.6 mag for the LAMP 2008, LAMP 2011, and LCO 2015.…”

A Test of the Formation Mechanism of the Broad Line Region in Active Galactic Nuclei

“…We use the time delay measurements of Hβ emission line summarized in Du et al (2015Du et al ( , 2016, which are compiled from the reverberation campaigns performed by different groups (Barth et al 2013, 2009b, 2014, Collier et al 1998, Dietrich et al 1993, 2015, Kaspi et al 2000, Pei et al 2014, Peterson et al 1991, 1992, 2002, 2014, Santos-Lleó et al 1997, 2001, Stirpe et al 1994, Wang et al 2014. The time delays represent the emissivity-weighted radii of the BLR in those RM objects.…”