[ Previous | Next | ADS ]

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)

Subjects: X-ray, Nova

Referred to by ATel #: 5546, 5573, 5593

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.