Faculty Research at Morehead State University
 

Authors

Dirk Grupe

Document Type

Article

Publication Date

11-2020

Abstract

In this contribution, we achieve the primary goal of the active galactic nucleus (AGN) STORM campaign by recovering velocity–delay maps for the prominent broad emission lines (Ly, C IV, He II, and H) in the spectrum of NGC5548. These are the most detailed velocity–delay maps ever obtained for an AGN, providing unprecedented information on the geometry, ionization structure, and kinematics of the broad-line region. Virial envelopes enclosing the emission-line responses show that the reverberating gas is bound to the black hole. A stratified ionization structure is evident. The He II response inside 5–10 light days has a broad single-peaked velocity profile. The Ly, C IV, and H responses extend from inside 2 to outside 20 light days, with double peaks at 2500 km s-1 in the 10–20 light-day delay range. An incomplete ellipse in the velocity–delay plane is evident in H. We interpret the maps in terms of a Keplerian disk with a well-defined outer rim at R = 20 light days. The far-side response is weaker than that from the near side. The line-center delay = (R=c)(1 - sin i) 5 days gives the inclination i 45. The inferred black hole mass is MBH 7107 M. In addition to reverberations, the fit residuals confirm that emission-line fluxes are depressed during the “BLR Holiday” identified in previous work. Moreover, a helical “Barber-Pole” pattern, with stripes moving from red to blue across the C IV and Ly line profiles, suggests azimuthal structure rotating with a 2 yr period that may represent precession or orbital motion of inner-disk structures casting shadows on the emission-line region farther out.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.