Very-high-frequency oscillations in the main peak of a magnetar giant flare

DOI: 
10.1038/s41586-021-04101-1
Publication date: 
24/12/2021
Main author: 
Castro-Tirado, A. J.
IAA authors: 
Castro-Tirado, A. J.;Pascual-Granado, J.;Caballero-García, M. D.;Castro Tirado, M. A.;Fernández-García, E.;Hu, Y. -D.;Rodríguez, E.;Sun, T.
Authors: 
Castro-Tirado, A. J.;Østgaard, N.;Göǧüş, E.;Sánchez-Gil, C.;Pascual-Granado, J.;Reglero, V.;Mezentsev, A.;Gabler, M.;Marisaldi, M.;Neubert, T.;Budtz-Jørgensen, C.;Lindanger, A.;Sarria, D.;Kuvvetli, I.;Cerdá-Durán, P.;Navarro-González, J.;Font, J. A.;Zhang, B. -B.;Lund, N.;Oxborrow, C. A.;Brandt, S.;Caballero-García, M. D.;Carrasco-García, I. M.;Castellón, A.;Castro Tirado, M. A.;Christiansen, F.;Eyles, C. J.;Fernández-García, E.;Genov, G.;Guziy, S.;Hu, Y. -D.;Nicuesa Guelbenzu, A.;Pandey, S. B.;Peng, Z. -K.;Pérez del Pulgar, C.;Reina Terol, A. J.;Rodríguez, E.;Sánchez-Ramírez, R.;Sun, T.;Ullaland, K.;Yang, S.
Journal: 
Nature
Publication type: 
Article
Volume: 
600
Pages: 
621
Abstract: 
Magnetars are strongly magnetized, isolated neutron stars<SUP>1-3</SUP> with magnetic fields up to around 10<SUP>15</SUP> gauss, luminosities of approximately 10<SUP>31</SUP>-10<SUP>36</SUP> ergs per second and rotation periods of about 0.3-12.0 s. Very energetic giant flares from galactic magnetars (peak luminosities of 10<SUP>44</SUP>-10<SUP>47</SUP> ergs per second, lasting approximately 0.1 s) have been detected in hard X-rays and soft γ-rays<SUP>4</SUP>, and only one has been detected from outside our galaxy<SUP>5</SUP>. During such giant flares, quasi-periodic oscillations (QPOs) with low (less than 150 hertz) and high (greater than 500 hertz) frequencies have been observed<SUP>6-9</SUP>, but their statistical significance has been questioned<SUP>10</SUP>. High-frequency QPOs have been seen only during the tail phase of the flare<SUP>9</SUP>. Here we report the observation of two broad QPOs at approximately 2,132 hertz and 4,250 hertz in the main peak of a giant γ-ray flare<SUP>11</SUP> in the direction of the NGC 253 galaxy<SUP>12-17</SUP>, disappearing after 3.5 milliseconds. The flare was detected on 15 April 2020 by the Atmosphere-Space Interactions Monitor instrument<SUP>18,19</SUP> aboard the International Space Station, which was the only instrument that recorded the main burst phase (0.8-3.2 milliseconds) in the full energy range (50 × 10<SUP>3</SUP> to 40 × 10<SUP>6</SUP> electronvolts) without suffering from saturation effects such as deadtime and pile-up. Along with sudden spectral variations, these extremely high-frequency oscillations in the burst peak are a crucial component that will aid our understanding of magnetar giant flares.
Database: 
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2021Natur.600..621C/abstract
ADS Bibcode: 
2021Natur.600..621C