Reverberation Mapping Measurements of Black Hole Masses and Broad-Line Region Kinematics in Mrk 817 and NGC 7469

Abstract

We present the results from a spectroscopic monitoring campaign to obtain reverberation-mapping measurements and investigate the broad-line region kinematics for active galactic nuclei (AGN) of Mrk 817 and NGC 7469. This campaign was undertaken with the Lijiang 2.4-meter telescope, the median spectroscopic sampling is 2.0 days for Mrk 817 and 1.0 days for NGC 7469. We detect time lags of the broad emission lines including Hβ, Hγ, He II and He I for both AGNs, and including Fe II for Mrk 817 with respect to the varying AGN continuum at 5100 Å. Investigating the relationship between line widths and time lags of the broad emission lines, we find that the BLR dynamics of Mrk 817 and NGC 7469 are consistent with the virial prediction. We estimate the masses of central supermassive black hole (SMBH) and the accretion rates of both AGNs. Using the data of this campaign, we construct the velocity-resolved lag profiles of the broad Hγ, Hβ, and He I lines for Mrk 817, which show almost the same kinematic signatures that the time lags in the red wing are slightly larger than the time lags in the blue wing. For NGC 7469, we only clearly construct the velocityresolved lag profiles of the broad Hγ and Hβ, which show very similar kinematic signatures to the BLR of Mrk 817. These signatures indicate that the BLR of Keplerian motion in both AGNs seemingly has outflowing components during the monitoring period. We discuss the kinematics of the BLR and the measurements including SMBH mass and accretion rates.

Broad-line region in NGC 4151 monitored by two decades of reverberation mapping campaigns. I. Evolution of structure and kinematics

“…As found in previous investigations for the other AGNs (e.g., Peterson & Wandel 2000;Peterson et al 2004;Lu et al 2016Lu et al , 2021Lu et al , 2022, the dynamics of the BLR is dominated by the gravitational potential of the central SMBH (i.e., the virial relation between the widths of broad emission lines and the time lags follow Δ𝑉 ∝ 𝜏 − 1 2 ). For NGC 4151, Li et al (2022) collected the previous RM results and combined their measurements.…”

“…The 1D brightness profiles show the data (black dots), the best-fit total model (red solid line) and the subcomponents (the blue dash line for PSF, the green, orange and red dotted-dashed lines for the bulge, the inner and outer disk, respectively). Lu et al 2021;Hu et al 2021a;Li et al 2022). For the first method, the emission fluxes are measured by a simple integration after subtracting a local background defined by two continuum windows.…”

“…Over the past four decades, the technique of reverberation mapping (Blandford & Payne 1982;Peterson 1993) has been well established as a powerful tool for measuring the masses of supermassive black holes (SMBHs) and investigating the geometry and dynamics of broad line regions (BLRs) in AGNs. There are now more than 100 AGNs with RM observations from different campaigns, e.g., Peterson et al (2004); Bentz et al (2006Bentz et al ( , 2009bBentz et al ( , 2010; Denney et al (2009aDenney et al ( , 2010; Du et al (2014Du et al ( , 2015Du et al ( , 2016aDu et al ( , 2018b; De Rosa et al (2018); Hu et al (2021a); Lu et al (2021); Li et al (2021) and Bao et al (2022). These efforts led to the discovery of the relationship between the characteristic radius of the BLR and optical 5100 Å luminosity (hereafter 𝑅 H𝛽 − 𝐿 5100 1 relationship; Kaspi et al 2000;Bentz et al 2009aBentz et al , 2013, which provides an economical way to estimate black hole (BH) masses from single-epoch spectra.…”