No X-rays detected from PNV J20233073+2046041 (= Nova Delphini 2013), 9 hours after discovery

ATel #5283; E. Kuulkers (ESA/ESAC, Spain), K. L. Page, J. P. Osborne (U. Leicester), N. P.M. Kuin (U. College London), K. V. Sokolovsky (ASC Lebedev/SAI MSU), J.-U. Ness (ESA/ESAC, Spain)
on 15 Aug 2013; 13:15 UT
Credential Certification: Erik Kuulkers (ekuulker@rssd.esa.int)

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Swift observed the recently discovered (CBET #3628) bright classical nova (ATels #5279, #5282) PNV J20233073+2046041 (= Nova Delphini 2013) between UT 2013 Aug 14 23:04 and Aug 15 00:52, for a total of 1.95 ks. No X-ray source at the position of the nova is seen with the XRT, with a 3-sigma upper limit of 0.007 cts/s (0.3-10 keV). The source is clearly visible in all three UV filters by the UVOT, but was too bright for useful UVOT photometry. We determine the following upper limits from the images: uvm2 < 9.45 mag, uvw1 < 10.0 mag, uvw2 < 10.0 mag.

The X-ray count-rate limit corresponds to an unabsorbed luminosity limit of about 3e31 erg s^-1 (0.3-10 keV) assuming the source is at 1 kpc, and assuming a 3 keV optically thin X-ray spectrum, absorbed by 1e21 atoms cm^-2. This luminosity limit was calculated under the assumption that optical loading is insignificant; this is unlikely to be the case for such a bright object.

We thank the Swift PI, Neil Gehrels, and the Swift mission operations team for the prompt observations.