Electronic Telegram No. 1030
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
M.S. 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT@CFA.HARVARD.EDU (science)
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V5116 SAGITTARII
     J.-U. Ness and S. Starrfield, Arizona State University; G. Schwarz,
West Chester University; K. L. Page and J. P. Osborne, Leicester University,
report, on behalf of the Swift nova-CV group, that the nova V5516 Sgr was
observed twice with Swift XRT.  The outburst was on 2005 July 4 (IAUC 8559),
and the first Swift observation on 2005 Aug. 29 (55.7 days after outburst)
yielded a marginal detection of 0.0012 +/- 0.001 counts per second (Ness et
al. 2007, Ap.J. 663, 505).  A second observation was carried out on 2007
Aug. 7.742 UT (763.75 days after outburst) with an exposure time of 3400 s.
The average count rate was 0.56 +/- 0.1 counts/s, and the spectrum is that
of a Super Soft X-ray Source.  Blackbody fits were attempted as a first
approximation, yielding a temperature of approximately 450000 K, but poor
fits were obtained, and the uncertainties in the extinction and distance are
quite large.  Observations with Swift are continuing, and observations at
other wavelengths are urged.
     According to visual magnitude estimates by J. Carvajal (Madrid, Spain),
this nova faded from mag 10.4 in late July 2005 to 11.5-11.9 in late
Sept. and early Oct. 2005.  According to E. Waagen, the last positive
observations of V5516 Sgr in the AAVSO database are from 2005 October, when
visual observer A. Jones (Nelson, New Zealand) estimated mag 12.0-12.3, and
CCD observer N. Butterworth (Mt. Louisa, Queensland, Australia) found V =
12.7-12.8.  Since Sept. 2006, the nova has been fainter than visual mag 13.0
to 14.0 according to A. Plummer (Linden, NSW, Australia), via the AAVSO.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2007 CBAT
2007 August 10                   (CBET 1030)              Daniel W. E. Green