Spectral and timing characterization of the X-ray source 1RXS J194211.9+255552

TL;DR

This study presents the first spectral and timing analysis of the transient X-ray source 1RXS J194211.9+255552, revealing a 166.5-day orbital period and characteristics consistent with Be X-ray binaries.

Contribution

It provides the first comprehensive spectral and timing characterization of this source, including the discovery of its orbital period and spectral properties.

Findings

Detected a 166.5-day orbital period.

X-ray emission concentrated in a specific phase interval.

Spectral shape consistent with Be X-ray binary systems.

Abstract

We report on the first spectral and timing characterization of the transient X-ray source 1RXS J194211.9+255552 using all available data from the Swift X-ray satellite. We used 10 years of hard X-ray data from the Burst Alert Telescope (BAT) to characterize its long-term behaviour and to search for long periodicities, finding evidence for a periodic modulation at 166.5 $\pm$ 0.5 d, that we interpret as the orbital period of the source. The folded light curve reveals that the X-ray emission is mostly concentrated in a restricted phase-interval and we propose to associate 1RXS J194211.9+255552 to the class of the Be X-ray binaries. This is also supported by the results of the spectral analysis, where we used the BAT data and three pointed Swift/XRT observations to characterize the X-ray broad-band spectral shape. We found mild spectral variability in soft X-rays that can be accounted for by a varying local neutral absorber, while the intrinsic emission is consistent with a hard power law multiplied by a high-energy exponential cut-off as typically observed in this class of systems.