Swift ToO Observations of Dwarf Nova PNV J19150199+0719471

ATel #5253; Chikako Nakata(Kyoto Univ.), Paul Kuin (University College London), Taichi Kato(Kyoto Univ.), Tomohito Ohshima (Kyoto Univ.)
on 6 Aug 2013; 20:15 UT
Credential Certification: Tomohito Ohshima (ohshima@kusastro.kyoto-u.ac.jp)

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We report on the Swift ToO observations of the recently discovered dwarf nova, PNV J19150199+0719471. The discovery of PNV J19150199+0719471, initially at V=10.8 magnitude, was reported by Koichi Itagaki on 2013 May 31, and the initial observations have been summarized in CBET 3554 and the web page of CBAT "Transient Object Followup Reports" at http://www.cbat.eps.harvard.edu/unconf/followups/J19150199+0719471.html As noted by T. Kato (vsnet-alert 15768), the nova position is consistent to a large proper motion object in e.g., the UCAC4 catalog (Zacharias et al. 2012, CDS catalog I/322A). The dwarf nova nature of this star is suggested by its color, and was confirmed by T. Garrel who observed in his low resolution spectra a double-peaked Halpha emission line (vsnet-alert 15779, see http://spektroskopieforum.vdsastro.de/viewtopic.php?p=23389#23389 ) which is indicative of accretion through a disk. Follow-up optical photometric observations have detected early superhumps with periods 0.05696(2) d (vsnet-alert 15817), and ordinary superhumps with periods 0.05821(1) d (vsnet-alert 15850). Swift XRT, and UVOT observations were performed June 11-14, and on June 28. The UVOT spectra were obtained with the uv grism each time. Photometric observations were also carried out with the uvm2, and uvw2 filters for the first set, and with the uvw1, and uvw2 filters for the second set. The AB magnitudes of the object were ~12.7 in the first set, and ~15.4 in the second set. In the first set of observations, there was a lot of variation in the UV spectral lines below 200nm. Although the spectra are noisy, strong variable (unidentified) absorption in the 1730-1790 range was observed which might be due Fe lines in circum-stellar matter. As yet unidentified emission peaks around 1840-1960 were present, shifting in wavelength between observations which may have been due to hot spots in the accretion flow. The XRT data, and UVOT data in the second observation set is being analysed. We are grateful to the Swift PI, Neil Gehrels, and the Swift mission operations team for their support of these observations.