Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The fast UV variability of the active galactic nucleus in Fairall 9   We present 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 (UVOT) on Swift, we find correlated optical/UV variability
on all time scales 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 4-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 time scale 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 > $8\times10^4$ 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.

21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
10
The categories of this paper are: q-bio