A Time-dependent Spectral Analysis of γ 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

doi:10.3847/1538-4357/ad944e

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A Time-dependent Spectral Analysis of γ Cassiopeiae

Journal article

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A Time-dependent Spectral Analysis of γ 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 and Norbert S. Schulz

The Astrophysical journal, Vol.978(1), p.105

01/01/2025

DOI: 10.3847/1538-4357/ad944e

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Abstract

We investigated the temporal and spectral features of γ Cassiopeiae’s X-ray emission within the context of the white dwarf (WD) 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 nonmagnetic cataclysmic variables. We then use this two-component insight to investigate previously unreported simultaneous XMM and NuSTAR data. The results of model fitting find WD properties consistent with optical studies alongside a significant secondary, thermal source. We propose a secondary shock between the Be decretion disk and WD accretion disk as the source. Finally, we analyzed a unique, low-count-rate event of the XMM light curve as potential evidence for the WD encountering Be decretion disk structures.

Be stars

Early-type emission stars

Gamma Cassiopeiae stars

High resolution spectroscopy

White dwarf stars

X-ray astronomy

Details

Title: Subtitle: A Time-dependent Spectral Analysis of γ Cassiopeiae
Creators: Sean J. Gunderson - Massachusetts Institute of Technology
David P. Huenemoerder - Massachusetts Institute of Technology
José M. Torrejón - University of Alicante
Dustin K. Swarm - University of Iowa
Joy S. Nichols - Center for Astrophysics Harvard & Smithsonian
Pragati Pradhan - Embry–Riddle Aeronautical University
Richard Ignace - East Tennessee State University
Hans Moritz Guenther - Massachusetts Institute of Technology
A. M. T. Pollock - University of Sheffield
Norbert S. Schulz - Massachusetts Institute of Technology
Resource Type: Journal article
Publication Details: The Astrophysical journal, Vol.978(1), p.105
DOI: 10.3847/1538-4357/ad944e
ISSN: 0004-637X
eISSN: 1538-4357
Publisher: The American Astronomical Society
Number of pages: 15
Grant note: GO3-24005X / National Aeronautics and Space Administration (NASA) (https://doi.org/10.13039/100000104) SV3-7301 / SI ∣ Smithsonian Astrophysical Observatory (SAO) (https://doi.org/10.13039/100009207)
Language: English
Date published: 01/01/2025
Academic Unit: Physics and Astronomy
Record Identifier: 9984934669402771

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