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arXiv · 2104.13378

Accurate flux calibration of GW170817: is the X-ray counterpart on the rise?

E. Troja·B. O'Connor·G. Ryan·L. Piro·R. Ricci·B. Zhang·T. Piran·G. Bruni·S. B. Cenko·H. van Eerten
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Abstract

X-ray emission from the gravitational wave transient GW170817 is well described as non-thermal afterglow radiation produced by a structured relativistic jet viewed off-axis. We show that the X-ray counterpart continues to be detected at 3.3 years after the merger. Such long-lasting signal is not a prediction of the earlier jet models characterized by a narrow jet core and a viewing angle of about 20 deg, and is spurring a renewed interest in the origin of the X-ray emission. We present a comprehensive analysis of the X-ray dataset aimed at clarifying existing discrepancies in the literature, and in particular the presence of an X-ray rebrightening at late times. Our analysis does not find evidence for an increase in the X-ray flux, but confirms a growing tension between the observations and the jet model. Further observations at radio and X-ray wavelengths would be critical to break the degeneracy between models.

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E. Troja, B. O'Connor, G. Ryan, L. Piro, R. Ricci, B. Zhang, T. Piran, G. Bruni, S. B. Cenko, H. van Eerten. 2021-04-27. Accurate flux calibration of GW170817: is the X-ray counterpart on the rise?. https://doi.org/10.1093/mnras/stab3533

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