Nova Del 2013 (V339 Del) is now a bright super-soft X-ray source
ATel #5505; Julian P Osborne, Kim Page, Andrew Beardmore (University of Leicester), Chick Woodward (University of Minnesota), Greg Schwarz (AAS), Mike Bode (Liverpool JM University), Jan-Uwe Ness (ESAC), Steve Shore (University of Pisa, INFN-Pisa), Sumner Starrfield (ASU), Mark Wagner (OSU), Fred Walter (SUNY)
on 24 Oct 2013; 15:47 UT
Credential Certification: Julian P Osborne (julo@star.le.ac.uk)
Regular Swift XRT monitoring of nova Del 2013 since our report in ATEL #5470 has revealed a decrease
in the high absorbing column affecting the optically thin harder X-ray emission above 1 keV; spectral fits suggest
N_H ~ 5x10^22 cm^-2 around day 45 and N_H ~ 1.8x10^22 around day 65 after discovery on Aug 14, 2013.
The super-soft X-ray source has been increasing in apparent brightness since it was first seen, the 0.3-1.0 keV grade 0 count rate is tabulated below
| UT Date | Day since detection | 0.3-1 keV XRT count/s |
| 2013 Oct 13 | 60.2 | 0.0067 +0.0014/-0.0011 |
| 2013 Oct 17 | 63.8 | 0.011 +/- 0.001 |
| 2013 Oct 20-21 | 67.4 | 0.023 +/- 0.002 |
| 2013 Oct 23 | 69.7 | 0.079 +/- 0.006 |
| 2013 Oct 24 | 70.8 | 1.5 +/- 0.2 |
The increase in count rate is exclusively below 0.7 keV, suggesting the unveiling of the hot white
dwarf photosphere.
We note that the recent more-rapid SSS brightening since day 67 coincides with an apparent plateau in the AAVSO V
band light curve.
We thank the Swift PI and operations team for their support of these observations.
