[vsnet-alert 8630] (fwd) Swift localization of XTE J1818-245 (ATEL)

[Taichi Kato]

(fwd) Swift localization of XTE J1818-245 (ATEL)

   The proposed optical counterpart becomes more likely the true one.
The object is sufficiently bright on unfiltered CCD images, and is a
very good target for a search for superhumps. -- more will be supplemented
by Uemura-san (?)

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The Astronomer's Telegram                   http://www.astronomerstelegram.org 
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Posted: Sat Aug 20 07:42:04 EDT 2005 -- Sun Aug 21 01:30:02 EDT 2005
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ATEL #588							     ATEL #588

Title:		Swift localization of XTE J1818-245
Author:	M. Still N. Gehrels (NASA/GSFC), D. Steeghs, M.A.P. Torres
		(CfA), O. Godet (U. Leicester), C. Brocksopp (MSSL)
Queries:	Martin.Still at gsfc.nasa.gov
Posted:	20 Aug 2005;  17:23  UT
Subjects:	Ultra-Violet, X-ray, Black Holes, Transients

The Swift observatory pointed at the X-ray transient XTE J1818-245 on
2005-08-20 between 06:18:52-06:21:02 UT. The X-ray source discovered
by Levine et al. (ATel #578), is still bright. Despite pileup in the
PC   detector mode (count rate = 72 c/s), the XRT localizes the source
to   within 7" (90% containment) of RA = 18h 18m 24.8s, Dec = -24d 32'
15"   (J2000). The optical counterpart identified by Steeghs et al. (ATel
#585) lies within the XRT error circle.      A 134s UVOT observation
was also performed through the UVW2 filter with   a central wavelength
of 1800 Angstroms. There is no source contained   within the XRT error
circle down to a 17.7 mag 5-sigma limit. UVOT   magnitudes are based on
Vega.  

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