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arXiv · 2408.00406

Anti-correlation between Flux and Photon Index of Hard X-ray Emission from The Crab

Koothodil Abhijith Augustine·Hsiang-Kuang Chang
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Abstract

Using \textit{Swift} Burst Alert Telescope (BAT) event-mode data during Gamma Ray Burst (GRB) occurrences, we conducted spectral analysis for the Crab system. From 38 good observations, which spans over a period of 18 years from 2006 to 2023, we found that the Crab's X-ray flux does not only flicker, but also significantly anti-correlates to its spectral power-law photon index. Since emission contribution of the Crab pulsar in this energy range is small, this anti-correlation is mainly about the emission of the Crab nebula. We suggest that this anti-correlation is an observational supporting evidence for the long-standing notion that the nebula emission is due to synchrotron radiation of shocked pulsar winds in the nebula.

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Koothodil Abhijith Augustine, Hsiang-Kuang Chang. 2024-08-01. Anti-correlation between Flux and Photon Index of Hard X-ray Emission from The Crab. https://arxiv.org/abs/2408.00406

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