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

TL;DR

This study analyzes the timing and spectral properties of GK Persei during its 2010 dwarf nova outburst, revealing persistent spin modulation and new soft X-ray features that suggest complex emission origins.

Contribution

It provides detailed timing and spectral analysis of GK Persei's 2010 outburst, highlighting new soft X-ray modulation not observed in previous outbursts.

Findings

Confirmed spin modulation at 351.3 seconds in 2-10 keV range.

Detected soft X-ray spin modulation during the second half of the outburst.

Indicated that soft X-ray emission may originate from magnetic poles and circumstellar material.

Abstract

GK Persei, an old nova and intermediate polar (IP), exhibited a dwarf nova (DN) outburst in 2010. This outburst was extensively observed by the Neil Gehrels Swift Observatory, beginning 1.95 days after the eruption and continuing until 13.9 days 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 Per may originate partly near the magnetic poles and partly from a wind or circumstellar material.