Aims: The launch of Swift has allowed many more novae to be observed regularly over the X-ray band. Such X-ray observations of novae can reveal ejecta shocks and the nuclear burning white dwarf, allowing estimates to be made of the ejecta velocity.
Methods: We analyse XMM-Newton and Swift X-ray and UV observations of the nova V598 Pup, which was initially discovered in the XMM-Newton slew survey. These data were obtained between 147 and 255 days after the nova outburst, and are compared with the earlier, brighter slew detection.
Results: The X-ray spectrum consists of a super-soft source, with the soft emission becoming hotter and much fainter between days ~147 and ~172 after the outburst, and a more slowly declining optically thin component, formed by shocks with kT ∼ 200-800 eV (corresponding to velocities of 400-800 km s-1). The main super-soft phase had a duration of less than 130 days. The Reflection Grating Spectrometer data show evidence of emission lines consistent with optically thin emission of kT ∼ 100 eV and place a limit on the density of the surrounding medium of log (n_e/cm-3) < 10.4 at the 90% level. The UV emission is variable over short timescales and fades by at least one magnitude (at λ ~ 2246-2600 Å) between days 169 and 255.
Astronomy and Astrophysics
- Pub Date:
- November 2009
- stars: individual: V598 Pup;
- stars: novae;
- cataclysmic variables;
- Astrophysics - High Energy Astrophysical Phenomena
- 6 pages, 5 figures, accepted for publication in A&