A SSS spectrum of V574 Pup
ATel #1327; J.-U. Ness, S. Starrfield (Arizona State), G. Schwarz (West Chester), J. P. Osborne and K. L. Page (University of Leicester)
on 14 Dec 2007; 16:52 UT
Credential Certification: Kim Page (kpa@star.le.ac.uk)
Subjects: Ultra-Violet, X-ray, Cataclysmic Variable, Nova, Transient
Two Swift XRT observations of V574 Pup were
carried out on 2007 December 7 and 13 with exposure times
of 6410 and 5450 seconds, respectively. The average
count rate is 0.014±0.001 counts per second.
All source photons were registered with energies below
1 keV and the spectrum is consistent with that of a
supersoft X-ray source (SSS). The count rate and the
spectrum are similar to the last X-ray observation taken
on 2005 August 17 (Ness et al. 2007, astro-ph/0703286),
The combined two spectra taken in 2007 can be fitted with
a blackbody yielding kT=32±10 eV and
NH=(4.2+1.9-1.1)1021
cm-2, leading to an observed X-ray flux
(0.3-1keV) of 3.7 10-13
erg cm-2 s-1 which, at
6.5kpc distance, corresponds to a bolometric luminosity of
8 1037 erg s-1.
Weak emission features may be present
at energies corresponding to emission lines
from NeIX, OVII, and NVII. The X-ray spectrum may be
composed of continuum plus emission lines.
We obtained UV magnitudes from UVOT for the December 13
observation and found 16.488±0.017 at 212nm (UVW2),
16.872±0.026 at 231nm (UVM2), and 16.289±0.015 at
291nm (UVW1), which corresponds to fluxes of
(1.37±0.02)10-15,
(8.10±0.02)10-17, and
(1.21±0.02)10-17 erg
s-1cm-2Ã
-1, respectively.
