Quasar Cartography: from Black Hole to Broad Line Region Scales

TL;DR

This paper introduces a generalized reverberation mapping method applicable to various data types, enabling simultaneous measurement of accretion disk and broad line region sizes in active galactic nuclei, validated on a sample of Seyfert 1 galaxies.

Contribution

It presents a new multivariate correlation analysis approach for reverberation mapping that works with photometric and spectroscopic data, improving AGN internal structure measurements.

Findings

Accretion disk and BLR sizes are measured simultaneously in most objects.

BLR sizes agree with independent spectroscopic reverberation mapping results.

Method enhances photometric RM applicability for large surveys.

Abstract

A generalized approach to reverberation mapping (RM) is presented, which is applicable to broad- and narrow-band photometric data, as well as to spectroscopic observations. It is based on multivariate correlation analysis techniques and, in its present implementation, is able to identify reverberating signals across the accretion disk and the broad line region (BLR) of active galactic nuclei (AGN). Statistical tests are defined to assess the significance of time-delay measurements using this approach, and the limitations of the adopted formalism are discussed. It is shown how additional constraints on some of the parameters of the problem may be incorporated into the analysis thereby leading to improved results. When applied to a sample of 14 Seyfert 1 galaxies having good-quality high-cadence photometric data, accretion disk scales and BLR sizes are simultaneously determined, on a case-by-case basis, in most objects. The BLR scales deduced here are in good agreement with the findings of independent spectroscopic RM campaigns. Implications for the photometric RM of AGN interiors in the era of large surveys are discussed.