A Reverberation-Based Black Hole Mass for MCG-06-30-15

TL;DR

This study measures the black hole mass in MCG-06-30-15 using reverberation mapping, confirming its consistency with established scaling relationships and multi-method estimates.

Contribution

It provides a reverberation-based black hole mass measurement for MCG-06-30-15, aligning with other methods and scaling relations, and offers insights into the BLR size relative to the dust torus.

Findings

Black hole mass of (1.6 ± 0.4) × 10^6 solar masses

Hβ time delay of 5.3 ± 1.8 days

Agreement with $R_{BLR}$-$L$ and $M_{BH}$-$\sigma_*$ relationships

Abstract

We present the results of a reverberation campaign targeting MGC-06-30-15. Spectrophotometric monitoring and broad-band photometric monitoring over the course of 4 months in the spring of 2012 allowed a determination of a time delay in the broad H$\beta$ emission line of $\tau=5.3\pm1.8$ days in the rest frame of the AGN. Combined with the width of the variable portion of the emission line, we determine a black hole mass of $M_{\rm BH} = (1.6 \pm 0.4) \times 10^6$ M$_{\odot}$. Both the H$\beta$ time delay and the black hole mass are in good agreement with expectations from the $R_{\rm BLR}$-$L$ and $M_{\rm BH}-\sigma_{\star}$ relationships for other reverberation-mapped AGNs. The H$\beta$ time delay is also in good agreement with the relationship between H$\beta$ and broad-band near-IR delays, in which the effective BLR size is $\sim 4-5$ times smaller than the inner edge of the dust torus. Additionally, the reverberation-based mass is in good agreement with estimates from the X-ray power spectral density break scaling relationship, and with constraints based on stellar kinematics derived from integral field spectroscopy of the inner $\sim 0.5$ kpc of the galaxy.