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arXiv · 2411.11825

A Time-Dependent Spectral Analysis of $\gamma$ Cassiopeiae

Sean J. Gunderson·David P. Huenemoerder·José M. Torrejón·Dustin K. Swarm·Joy S. Nichols·Pragati Pradhan·Richard Ignace·Hans Moritz Guenther·A. M. T. Pollock·Norbert S. Schulz
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Abstract

We investigated the temporal and spectral features of $\gamma$ Cassiopeiae's X-ray emission within the context of the white dwarf accretion hypothesis. We find that the variabilities present in the X-ray data show two different signals, one primarily due to absorption and the other due to flickering like in non-magnetic cataclysmic variables. We then use this two-component insight to investigate previously un-reported simultaneous XMM and NuSTAR data. The model fitting results find white dwarf properties consistent with optical studies alongside a significant secondary, thermal source. We propose a secondary shock between the Be decretion disk and white dwarf accretion disk as the source. Finally, we analyzed a unique, low-count rate event of the XMM light curve as potential evidence for the white dwarf encountering Be decretion disk structures.

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Sean J. Gunderson, David P. Huenemoerder, José M. Torrejón, Dustin K. Swarm, Joy S. Nichols, Pragati Pradhan, Richard Ignace, Hans Moritz Guenther, A. M. T. Pollock, Norbert S. Schulz. 2024-11-18. A Time-Dependent Spectral Analysis of $\gamma$ Cassiopeiae. https://doi.org/10.3847/1538-4357%2Fad944e

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