학술논문
Space Telescope and Optical Reverberation Mapping Project. IX. Velocity–Delay Maps for Broad Emission Lines in NGC 5548
Document Type
article
Author
Horne, Keith; De Rosa, G; Peterson, BM; Barth, AJ; Ely, J; Fausnaugh, MM; Kriss, GA; Pei, L; Bentz, MC; Cackett, EM; Edelson, R; Eracleous, M; Goad, MR; Grier, CJ; Kaastra, J; Kochanek, CS; Krongold, Y; Mathur, S; Netzer, H; Proga, D; Tejos, N; Vestergaard, M; Villforth, C; Adams, SM; Anderson, MD; Arévalo, P; Beatty, TG; Bennert, VN; Bigley, A; Bisogni, S; Borman, GA; Boroson, TA; Bottorff, MC; Brandt, WN; Breeveld, AA; Brotherton, M; Brown, JE; Brown, JS; Canalizo, G; Carini, MT; Clubb, KI; Comerford, JM; Corsini, EM; Crenshaw, DM; Croft, S; Croxall, KV; Bontà, E Dalla; Deason, AJ; Dehghanian, M; De Lorenzo-Cáceres, A; Denney, KD; Dietrich, M; Done, C; Efimova, NV; Evans, PA; Ferland, GJ; Filippenko, AV; Flatland, K; Fox, OD; Gardner, E; Gates, EL; Gehrels, N; Geier, S; Gelbord, JM; Gonzalez, L; Gorjian, V; Greene, JE; Grupe, D; Gupta, A; Hall, PB; Henderson, CB; Hicks, S; Holmbeck, E; Holoien, TW-S; Hutchison, T; Im, M; Jensen, JJ; Johnson, CA; Joner, MD; Jones, J; Kaspi, S; Kelly, PL; Kennea, JA; Kim, M; Kim, S; Kim, SC; King, A; Klimanov, SA; Korista, KT; Lau, MW; Lee, JC; Leonard, DC; Li, Miao; Lira, P; Lochhaas, C; Ma, Zhiyuan; MacInnis, F; Malkan, MA; Manne-Nicholas, ER; Mauerhan, JC
Source
The Astrophysical Journal. 907(2)
Subject
Language
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 (Lyα, C iv, He ii, and Hβ) in the spectrum of NGC 5548. 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 lt-day has a broad single-peaked velocity profile. The Lyα, C iv, and Hβ responses extend from inside 2 to outside 20 lt-day, with double peaks at ±2500 km s-1 in the 10-20 lt-day delay range. An incomplete ellipse in the velocity-delay plane is evident in Hβ. We interpret the maps in terms of a Keplerian disk with a well-defined outer rim at R = 20 lt-day. The far-side response is weaker than that from the near side. The line-center delay days gives the inclination i ≈ 45°. The inferred black hole mass is M BH ≈ 7 × 107 M o˙. 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 Lyα 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.