Timing and Spectral Evolution of the Magnetar 1E 1841-045 in Outburst

Fuente: arXiv
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Autores principales: Younes, G., Lander, S. K., Baring, M. G., Bause, M. L., Stewart, R., Arzoumanian, Z., Thi, H. Dinh, Enoto, T., Gendreau, K., Guver, T., Harding, A. K., Ho, W. C. G., Hu, C. -P., van Kooten, A., Kouveliotou, C., Di Lalla, N., McEwen, A., Negro, M., Ng, Mason, Palmer, D. M., Spitler, L. G., Wadiasingh, Zorawar
Formato: Preprint
Publicado: 2025
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author Younes, G.
Lander, S. K.
Baring, M. G.
Bause, M. L.
Stewart, R.
Arzoumanian, Z.
Thi, H. Dinh
Enoto, T.
Gendreau, K.
Guver, T.
Harding, A. K.
Ho, W. C. G.
Hu, C. -P.
van Kooten, A.
Kouveliotou, C.
Di Lalla, N.
McEwen, A.
Negro, M.
Ng, Mason
Palmer, D. M.
Spitler, L. G.
Wadiasingh, Zorawar
author_facet Younes, G.
Lander, S. K.
Baring, M. G.
Bause, M. L.
Stewart, R.
Arzoumanian, Z.
Thi, H. Dinh
Enoto, T.
Gendreau, K.
Guver, T.
Harding, A. K.
Ho, W. C. G.
Hu, C. -P.
van Kooten, A.
Kouveliotou, C.
Di Lalla, N.
McEwen, A.
Negro, M.
Ng, Mason
Palmer, D. M.
Spitler, L. G.
Wadiasingh, Zorawar
contents We present the timing and spectral analyses of the NICER, NuSTAR, and IXPE observations of the magnetar 1E 1841-045 covering 82 days following its August 2024 bursting activity as well as radio observations utilizing MeerKAT and Effelsberg. We supplement our study with a historical NuSTAR and all 2024 pre-outburst NICER observations. The outburst is marked by an X-ray flux enhancement of a factor 1.6 compared to the historical level, predominantly driven by a newly-formed non-thermal emitting component with a photon index $Γ=1.5$. This flux showed a 20% decay at the end of our monitoring campaign. The radio monitoring did not reveal any pulsed radio emission with an upper-limit of 20 mJy and 50 mJy ms on the mean flux density and single pulse fluence, respectively. We detect a spin-up glitch at outburst onset with a $Δν=6.1\times10^{-8}$ Hz and a $Δ\dotν=-1.4\times10^{-14}$ Hz s$^{-1}$, consistent with the near-universality of this behavior among the continuously-monitored magnetars. Most intriguingly, the 1E 1841-045 2-10 keV pulse profile is markedly different compared to pre-outburst; it shows a new, narrow (0.1 cycles) peak that appears to shift towards merging with the main, persistently-present, pulse. This is the second case of pulse-peak migration observed in magnetars after SGR 1830$-$0645, and the two sources exhibit a similar rate of phase shift. This implies that this phenomenon is not unique and might present itself in the broader population. The newly-formed peak for 1E 1841-045 is non-thermal, with emission extending to $\gtrsim20$ keV, in contrast to the case of SGR 1830$-$0645. Our results are consistent with an untwisting magnetic field bundle with migration towards the magnetic pole, perhaps accompanied by plastic motion of the crust.
format Preprint
id arxiv_https___arxiv_org_abs_2502_20079
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Timing and Spectral Evolution of the Magnetar 1E 1841-045 in Outburst
Younes, G.
Lander, S. K.
Baring, M. G.
Bause, M. L.
Stewart, R.
Arzoumanian, Z.
Thi, H. Dinh
Enoto, T.
Gendreau, K.
Guver, T.
Harding, A. K.
Ho, W. C. G.
Hu, C. -P.
van Kooten, A.
Kouveliotou, C.
Di Lalla, N.
McEwen, A.
Negro, M.
Ng, Mason
Palmer, D. M.
Spitler, L. G.
Wadiasingh, Zorawar
High Energy Astrophysical Phenomena
We present the timing and spectral analyses of the NICER, NuSTAR, and IXPE observations of the magnetar 1E 1841-045 covering 82 days following its August 2024 bursting activity as well as radio observations utilizing MeerKAT and Effelsberg. We supplement our study with a historical NuSTAR and all 2024 pre-outburst NICER observations. The outburst is marked by an X-ray flux enhancement of a factor 1.6 compared to the historical level, predominantly driven by a newly-formed non-thermal emitting component with a photon index $Γ=1.5$. This flux showed a 20% decay at the end of our monitoring campaign. The radio monitoring did not reveal any pulsed radio emission with an upper-limit of 20 mJy and 50 mJy ms on the mean flux density and single pulse fluence, respectively. We detect a spin-up glitch at outburst onset with a $Δν=6.1\times10^{-8}$ Hz and a $Δ\dotν=-1.4\times10^{-14}$ Hz s$^{-1}$, consistent with the near-universality of this behavior among the continuously-monitored magnetars. Most intriguingly, the 1E 1841-045 2-10 keV pulse profile is markedly different compared to pre-outburst; it shows a new, narrow (0.1 cycles) peak that appears to shift towards merging with the main, persistently-present, pulse. This is the second case of pulse-peak migration observed in magnetars after SGR 1830$-$0645, and the two sources exhibit a similar rate of phase shift. This implies that this phenomenon is not unique and might present itself in the broader population. The newly-formed peak for 1E 1841-045 is non-thermal, with emission extending to $\gtrsim20$ keV, in contrast to the case of SGR 1830$-$0645. Our results are consistent with an untwisting magnetic field bundle with migration towards the magnetic pole, perhaps accompanied by plastic motion of the crust.
title Timing and Spectral Evolution of the Magnetar 1E 1841-045 in Outburst
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2502.20079