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Main Authors: Basu, Judhajeet, Anupama, G. C., Ness, Jan-Uwe, Singh, Kulinder Pal, Barway, Sudhanshu, Chamoli, Shatakshi
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.11231
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author Basu, Judhajeet
Anupama, G. C.
Ness, Jan-Uwe
Singh, Kulinder Pal
Barway, Sudhanshu
Chamoli, Shatakshi
author_facet Basu, Judhajeet
Anupama, G. C.
Ness, Jan-Uwe
Singh, Kulinder Pal
Barway, Sudhanshu
Chamoli, Shatakshi
contents We report on UV and X-ray observations of the 2024 eruption of the recurrent nova LMCN 1968-12a, a rapidly recurring extragalactic system with a $\sim$4.3 year recurrence period and a massive white dwarf (WD). The eruption was discovered on 2024 August 1.8 by \textit{Swift}, and subsequently monitored using \textit{AstroSat}'s UVIT and SXT, along with Swift/UVOT and XRT. The multi-wavelength light curves reveal a rapid UV-optical decline, followed by a plateau phase exhibiting 1.26-day modulations consistent with the orbital period. The Supersoft (SSS) X-ray emission, that emerged by day 5, exhibited a double peak, suggesting variable obscuration that could be due to an inhomogeneous nova ejecta or due to a nova super-remnant along the line of sight. Time-resolved X-ray spectroscopy shows a blackbody component with T $\approx 10^6$ K. The SEDs obtained concurrently in the UV, peaking at T $\approx$ 20,000 K and with a source radius $\sim$2-3 R$_\odot$, are inconsistent with emission from the secondary star or nova photosphere alone. Instead, the UV emission is attributed to an irradiated accretion disk that survived the eruption. The persistent UV plateau and its temperature suggest that the accretion disk was not completely disrupted and resumed activity within days, consistent with recent findings in other rapidly recurring novae such as U~Sco and M31N~2008-12a.
format Preprint
id arxiv_https___arxiv_org_abs_2510_11231
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Survival of the accretion disk in LMC Recurrent Nova 1968-12a: UV--X-ray case study of the 2024 eruption
Basu, Judhajeet
Anupama, G. C.
Ness, Jan-Uwe
Singh, Kulinder Pal
Barway, Sudhanshu
Chamoli, Shatakshi
High Energy Astrophysical Phenomena
We report on UV and X-ray observations of the 2024 eruption of the recurrent nova LMCN 1968-12a, a rapidly recurring extragalactic system with a $\sim$4.3 year recurrence period and a massive white dwarf (WD). The eruption was discovered on 2024 August 1.8 by \textit{Swift}, and subsequently monitored using \textit{AstroSat}'s UVIT and SXT, along with Swift/UVOT and XRT. The multi-wavelength light curves reveal a rapid UV-optical decline, followed by a plateau phase exhibiting 1.26-day modulations consistent with the orbital period. The Supersoft (SSS) X-ray emission, that emerged by day 5, exhibited a double peak, suggesting variable obscuration that could be due to an inhomogeneous nova ejecta or due to a nova super-remnant along the line of sight. Time-resolved X-ray spectroscopy shows a blackbody component with T $\approx 10^6$ K. The SEDs obtained concurrently in the UV, peaking at T $\approx$ 20,000 K and with a source radius $\sim$2-3 R$_\odot$, are inconsistent with emission from the secondary star or nova photosphere alone. Instead, the UV emission is attributed to an irradiated accretion disk that survived the eruption. The persistent UV plateau and its temperature suggest that the accretion disk was not completely disrupted and resumed activity within days, consistent with recent findings in other rapidly recurring novae such as U~Sco and M31N~2008-12a.
title Survival of the accretion disk in LMC Recurrent Nova 1968-12a: UV--X-ray case study of the 2024 eruption
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2510.11231