Swift observations of the fading of V339 Del.
ATel #5967; K. L. Page (U. Leicester), N. P. Kuin (UCL-MSSL), J. P. Osborne (U. Leicester), G. J. Schwarz (AAS), S. N. Shore (U. Pisa and INFN-Pisa), S. Starrfield (ASU) & C. E. Woodward (U. Minn.)
on 10 Mar 2014; 17:33 UT
Credential Certification: Kim Page (kpa@star.le.ac.uk)
Subjects: Ultra-Violet, X-ray, Nova
Referred to by ATel #: 6088
V339 Del (Nova Del 2013) has recently emerged from the Swift Sun
constraint. The final observation before the start of the constraint, on 2014
January 6 (day 144.5 after optical detection), yielded an X-ray count
rate of ~40 count s-1. However, by March 4 (day 202), the
count rate had dropped to ~0.8 count s-1. A further series
of observations on March 9 (day 206-207) revealed a continued
count rate decline to ~0.4 count s-1.
Despite the drop in count rate, the current X-ray spectrum of V339
Del is still soft, with almost all counts below 1 keV, and can be
modelled with blackbody of ~ 40 eV, with NH ~ 5 x
1020 cm-2 (+/- 50%).
The Swift-UVOT is now collecting both photometry and grism data, with
the UV magnitudes being around 11 in all three filters (close to the
coincidence loss limit). The grism UV spectrum shows a weak continuum with bright emission lines of NIII (1752 A), weak Al III (1860 A), C III] (1909 A), N IV] (2151 A), [O III] (2321 A), O II] (2471 A), Mg II (2800 A) and Ne V (3426 A).
