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Title: The fast UV variability of the active galactic nucleus in Fairall 9

We present the results from a new optical/UV/X-ray monitoring campaign of the luminous Seyfert galaxy Fairall 9 using the Swift satellite. Using the UV-Optical Telescope on Swift, we find correlated optical/UV variability on all timescales ranging from the sampling time (4 days) to the length of the campaign (2.5 months). In one noteworthy event, the UW2-band flux dips by 20% in four days, and then recovers equally quickly; this event is not seen in either the optical or the X-ray bands. We argue that this event provides further evidence that a significant fraction of the UV-emission must be driven by irradiation/reprocessing of emission from the central disk. We also use an archival XMM-Newton observation to examine shorter timescale UV/X-ray variability. We find very rapid (<10 ks) UV flares of small amplitude. We show that, unless this emission is non-thermal, we must be seeing the Wien tail from a compact (<3 light hours), hot (T > 8 × 10{sup 4} K) region. The possible association with X- ray microflares suggests that we may be seeing the UV signatures of direct X-ray flare heating of the innermost disk.
Authors:
; ; ;  [1] ;  [2]
  1. Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States)
  2. Stevenson University, 1525 Greenspring Valley Rd, Stevenson, MD 21153 (United States)
Publication Date:
OSTI Identifier:
22356709
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; EMISSION; GALAXY NUCLEI; HEATING; IRRADIATION; SATELLITES; SEYFERT GALAXIES; TELESCOPES; ULTRAVIOLET RADIATION; VISIBLE RADIATION; X RADIATION; X-RAY GALAXIES