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IF 1.1 4区物理与天体物理 Q3 ASTRONOMY & ASTROPHYSICS

Astronomische Nachrichten Pub Date : 2024-12-22 DOI:10.1002/asna.20240106

Felix Fürst, Dominic J. Walton, Matteo Bachetti, Hannah Earnshaw, Murray Brightman

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引用次数: 0

摘要

在过去的 8 年中，XMM-牛顿、NuSTAR 和 Swift 对超光速 X 射线脉冲星（ULXP）NGC 7793 P13 进行了定期监测。在此，我们将介绍这次监测活动在脉冲周期演变和光谱变异性方面的最新结果。我们发现，自从该源在 2020-2022 年从 X 射线低状态恢复以来，自旋上升率与关闭状态之前相比有了显著增加，尽管 X 射线光度并没有显示出同等的增长。我们发现 X 射线和光学/紫外线通量是反相关的，并推测这种变化可能是由一个大型吸积盘驱动的，该吸积盘以 7-8 年的超轨道周期进行前冲。我们研究了 XMM-Newton 和 NuSTAR 数据中的光谱行为，发现尽管通量变化很大，但光谱形状变化很小。这种光谱一致性进一步表明，观测到的通量变化是一种几何效应，而不是由于吸积率的内在变化造成的。

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The Surprising Long-Term Evolution of the ULXP NGC 7793 P13

The ultra-luminous x-ray pulsar (ULXP) NGC 7793 P13 has been regularly monitored with XMM-Newton, NuSTAR, and Swift for the last 8 years. Here, we present the latest results of this monitoring campaign with respect to the pulse period evolution and spectral variability. We find that since the source recovered from an x-ray low state in 2020–2022 the spin-up rate has increased significantly compared with before the off-state, even though the x-ray luminosity has not shown an equivalent increase. We find that the x-ray and optical/UV flux are anti-correlated, and speculate that this variability might be driven by a large accretion disk, precessing at a super-orbital period of 7–8 years. We study the spectral behavior in the XMM-Newton and NuSTAR data, and find very little changes in the spectral shape, despite the large flux variability. This spectral consistency provides further indication that the observed flux variability is a geometric effect and not due to intrinsic changes of the accretion rate.

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来源期刊

Astronomische Nachrichten 地学天文-天文与天体物理

CiteScore

1.80

自引率

11.10%

发文量

审稿时长

4-8 weeks

期刊介绍： Astronomische Nachrichten, founded in 1821 by H. C. Schumacher, is the oldest astronomical journal worldwide still being published. Famous astronomical discoveries and important papers on astronomy and astrophysics published in more than 300 volumes of the journal give an outstanding representation of the progress of astronomical research over the last 180 years. Today, Astronomical Notes/ Astronomische Nachrichten publishes articles in the field of observational and theoretical astrophysics and related topics in solar-system and solar physics. Additional, papers on astronomical instrumentation ground-based and space-based as well as papers about numerical astrophysical techniques and supercomputer modelling are covered. Papers can be completed by short video sequences in the electronic version. Astronomical Notes/ Astronomische Nachrichten also publishes special issues of meeting proceedings.