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Main Authors: Boztepe, Tugba, Guver, Tolga, Devecioglu, Elif Ece, Speicher, Julia, Serino, Motoko, Ballantyne, David R., Altamirano, Diego, Jaisawal, Gaurava K., Ng, Mason, Sanna, Andrea, Gungor, Can, Iwakiri, Wataru
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.02713
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author Boztepe, Tugba
Guver, Tolga
Devecioglu, Elif Ece
Speicher, Julia
Serino, Motoko
Ballantyne, David R.
Altamirano, Diego
Jaisawal, Gaurava K.
Ng, Mason
Sanna, Andrea
Gungor, Can
Iwakiri, Wataru
author_facet Boztepe, Tugba
Guver, Tolga
Devecioglu, Elif Ece
Speicher, Julia
Serino, Motoko
Ballantyne, David R.
Altamirano, Diego
Jaisawal, Gaurava K.
Ng, Mason
Sanna, Andrea
Gungor, Can
Iwakiri, Wataru
contents Superbursts are rare events observed from bursting neutron star low mass X-ray binaries. They are thought to originate from unstable burning of the thick layer of Carbon on the surface of the neutron star, causing the observed X-ray flashes to last several hours. Given their fluence it has long been thought that superbursts may have significant effects on the accretion flow around the neutron star. In this paper, we first present evidence for a new superburst observed from 4U 1608-522 by MAXI during the 2020 outburst, around 00:45 UTC on 16 July 2020. We compare some of the properties of this superburst and the underlying outburst with the events recorded on May 5 2005 by RXTE and most recently in 2025 by MAXI. We then present our spectral analysis of NICER and Insight-HXMT data obtained before and after the 2020 superburst event. Our results indicate that the inner disk temperature and the radius show a systematic evolution in the following few days, which may be related to the superburst. We show that the timescale of the observed evolution can not be governed by viscous timescales unless the viscosity parameter is unrealistically low.
format Preprint
id arxiv_https___arxiv_org_abs_2509_02713
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The 2020 Superburst of 4U 1608-522 and its impact on the accretion disk
Boztepe, Tugba
Guver, Tolga
Devecioglu, Elif Ece
Speicher, Julia
Serino, Motoko
Ballantyne, David R.
Altamirano, Diego
Jaisawal, Gaurava K.
Ng, Mason
Sanna, Andrea
Gungor, Can
Iwakiri, Wataru
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
Superbursts are rare events observed from bursting neutron star low mass X-ray binaries. They are thought to originate from unstable burning of the thick layer of Carbon on the surface of the neutron star, causing the observed X-ray flashes to last several hours. Given their fluence it has long been thought that superbursts may have significant effects on the accretion flow around the neutron star. In this paper, we first present evidence for a new superburst observed from 4U 1608-522 by MAXI during the 2020 outburst, around 00:45 UTC on 16 July 2020. We compare some of the properties of this superburst and the underlying outburst with the events recorded on May 5 2005 by RXTE and most recently in 2025 by MAXI. We then present our spectral analysis of NICER and Insight-HXMT data obtained before and after the 2020 superburst event. Our results indicate that the inner disk temperature and the radius show a systematic evolution in the following few days, which may be related to the superburst. We show that the timescale of the observed evolution can not be governed by viscous timescales unless the viscosity parameter is unrealistically low.
title The 2020 Superburst of 4U 1608-522 and its impact on the accretion disk
topic High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2509.02713