The 2020 Superburst of 4U 1608-522 and its impact on the accretion disk
The 2020 Superburst of 4U 1608-522 and its impact on the accretion disk
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.
astro-ph.HE, hep-ph
1146-1157
Boztepe, Tugba
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Guver, Tolga
5fdfca08-f31f-4aff-8802-9f6e1948b545
Devecioglu, Elif Ece
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Speicher, Julia
ab79e30b-5e96-417e-9470-74e0040260f9
Serino, Motoko
71bc12f7-d036-4153-96c8-7ee4fd31d466
Ballantyne, David R.
e034d251-0b2f-40b0-8b9c-3f8eb655b836
Altamirano, Diego
d5ccdb09-0b71-4303-9538-05b467be075b
Jaisawal, Gaurava K.
45038eb4-e00c-4cf9-b1b4-42fd4ac345f9
Ng, Mason
1ea126a4-d65f-4ea4-a97b-dd8620d745e4
Sanna, Andrea
f132c9e7-4e3e-4d3a-84a3-85f5724b5f4d
Gungor, Can
566e4c11-5d8d-4a04-8e40-61349fd41a98
Iwakiri, Wataru
f775fbdf-db7e-4f07-afdf-67067173a1c5
29 September 2025
Boztepe, Tugba
7db982e5-6633-436f-9600-9ef98ae1b589
Guver, Tolga
5fdfca08-f31f-4aff-8802-9f6e1948b545
Devecioglu, Elif Ece
d706bd13-0f01-4662-8443-9e85a6b5257c
Speicher, Julia
ab79e30b-5e96-417e-9470-74e0040260f9
Serino, Motoko
71bc12f7-d036-4153-96c8-7ee4fd31d466
Ballantyne, David R.
e034d251-0b2f-40b0-8b9c-3f8eb655b836
Altamirano, Diego
d5ccdb09-0b71-4303-9538-05b467be075b
Jaisawal, Gaurava K.
45038eb4-e00c-4cf9-b1b4-42fd4ac345f9
Ng, Mason
1ea126a4-d65f-4ea4-a97b-dd8620d745e4
Sanna, Andrea
f132c9e7-4e3e-4d3a-84a3-85f5724b5f4d
Gungor, Can
566e4c11-5d8d-4a04-8e40-61349fd41a98
Iwakiri, Wataru
f775fbdf-db7e-4f07-afdf-67067173a1c5
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 and Iwakiri, Wataru
(2025)
The 2020 Superburst of 4U 1608-522 and its impact on the accretion disk.
Monthly Notices of the Royal Astronomical Society, 543 (2), .
(doi:10.1093/mnras/staf1502).
Abstract
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.
Text
2509.02713v1
- Author's Original
Available under License Other.
Text
staf1502
- Version of Record
More information
Accepted/In Press date: 1 September 2025
e-pub ahead of print date: 9 September 2025
Published date: 29 September 2025
Keywords:
astro-ph.HE, hep-ph
Identifiers
Local EPrints ID: 507345
URI: http://eprints.soton.ac.uk/id/eprint/507345
ISSN: 1365-2966
PURE UUID: c7bfb56c-d13b-4068-946d-caf1138547ac
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Date deposited: 04 Dec 2025 17:59
Last modified: 05 Dec 2025 02:45
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Contributors
Author:
Tugba Boztepe
Author:
Tolga Guver
Author:
Elif Ece Devecioglu
Author:
Julia Speicher
Author:
Motoko Serino
Author:
David R. Ballantyne
Author:
Gaurava K. Jaisawal
Author:
Mason Ng
Author:
Andrea Sanna
Author:
Can Gungor
Author:
Wataru Iwakiri
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