No abstract

In this contribution, we achieve the primary goal of the AGN STORM campaign by recovering velocity-delay maps, which are the key to understanding the geometry, ionization structure, and kinematics of the broadline region, for the prominent broad emission lines, Lyα, C IV, He II and Hβ, in the spectrum of NGC 5548. The emission-line responses inhabit the interior of a virial envelope. The velocity-delay maps reveal stratified ionization structure. The He II response inside 5-10 light days has a broad single-peaked velocity profile. The Lyα, C IV, and Hβ responses peak inside 10 light days, extend outside 20 light days, and exhibit a velocity profile with two peaks separated by 5000 km s −1 in the 10-20 light-day delay range. The velocity-delay maps show that the "M"-shaped lag vs. velocity structure found in previous cross-correlation analysis is the signature of a Keplerian disk with a well-defined outer edge at R/c = 20 light days. The outer wings of the "M" arise from the virial envelope, and the "U"-shaped interior of the "M" is the lower half of an ellipse in the velocity-delay plane. The far side response is weaker than that from the near side, so that we see clearly the lower half, but only faintly the upper half, of the velocity-delay ellipse. The delay τ = (R/c)(1 − sin i) = 5 light days at line center is from the near edge of the inclined ring, giving the inclination i = 45 • . A black hole mass of M BH = 7 × 10 7 M is consistent with the velocity-delay structure. A 'barber pole' pattern with stripes moving from red to blue across the C IV and possibly Lyα line profiles suggests the presence of azimuthal structure rotating around the far side of the broad-line region and may be the signature of precession or orbital motion of structures in the inner disk. Further HST observations of NGC 5548 over a multi-year timespan but with a cadence of perhaps 10 days rather than 1 day could help to clarify the nature of this new AGN phenomenon.

No abstract

No abstract

No abstract