Timing and spectral analysis of GK Persei during the 2010 dwarf nova outburst

ABSTRACT GK Persei, an old nova and intermediate polar, exhibited a dwarf nova outburst in 2010. This outburst was extensively observed by the Neil Gehrels Swift Observatory, beginning 1.95 d after the eruption and continuing until 13.9 d before the maximum of the outburst in the optical. In this paper, we present timing and spectral analyses, comparing the results with those of other outbursts. We confirm the spin modulation in the 2–10 keV X-ray range with a period of $P_{\rm WD} = 351.325(9)$ s. Additionally, we detected spin modulation in the 0.3–2 keV band during the second half of the observations, a feature not seen in the 2015 and 2018 outbursts. This finding suggests that the soft X-ray emission in GK Persei may originate partly near the magnetic poles and partly from a wind or circumstellar material.