The anomalous X-ray pulsar 4U 0142＋61 has been studied with obser- vations from INTEGRAL. The hard X-ray spectrum in the range 18-500 keV for 4U 0142＋61 was derived using nearly nine years of INTEGRAL/IBIS data. We ...The anomalous X-ray pulsar 4U 0142＋61 has been studied with obser- vations from INTEGRAL. The hard X-ray spectrum in the range 18-500 keV for 4U 0142＋61 was derived using nearly nine years of INTEGRAL/IBIS data. We ob- tained the average hard X-ray spectrum of 4U 0142＋61 with all available data. The spectrum of 4U 0142＋61 can be fitted with a power law that includes an exponen- tial high energy cutoff. This average spectrum is well fitted by a power law with r ,~ 0.51 ± 0.11 plus a cutoff energy at 128.6 ± 17.2 keV. The hard X-ray flux of the source from 20-150 keV showed no significant variations （within 20%） from 2003- 2011. The spectral profiles have some variability over the nine years such that the photon index varies from 0.3-1.5 and the cutoff energies from 110-250 keV. The de- tection of the high energy cutoff around 130 keV shows some constraints on the radia- tion mechanisms of magnetars and possibly probes the differences between magnetar and accretion models for this special class of neutron stars. Future HXMTobservations could provide stronger constraints on the hard X-ray spectral properties of this source and other magnetar candidates.展开更多
The detection of quasi-periodic oscillations(QPOs)in magnetar giant flares(GFs)has brought a new perspective to studies of the mechanism of magnetar bursts.Due to the scarcity of GFs,searching for QPOs in magnetar sho...The detection of quasi-periodic oscillations(QPOs)in magnetar giant flares(GFs)has brought a new perspective to studies of the mechanism of magnetar bursts.Due to the scarcity of GFs,searching for QPOs in magnetar short bursts is reasonable.Here we report the detection of a narrow QPO at approximately 110 Hz and a wide QPO at approximately 60 Hz in the short magnetar burst SGR 150228213,with a confidence level of 3.35σ.This burst was initially attributed to 4U 0142+61 by Fermi/GBM on location,but we have not detected such QPOs in other bursts from this magnetar.We also found that there was a repeating fast radio burst associated with SGR 150228213 on location.Finally,we discuss the possible origins of SGR 150228213.展开更多
基金Supported by the National Natural Science Foundation of China
文摘The anomalous X-ray pulsar 4U 0142＋61 has been studied with obser- vations from INTEGRAL. The hard X-ray spectrum in the range 18-500 keV for 4U 0142＋61 was derived using nearly nine years of INTEGRAL/IBIS data. We ob- tained the average hard X-ray spectrum of 4U 0142＋61 with all available data. The spectrum of 4U 0142＋61 can be fitted with a power law that includes an exponen- tial high energy cutoff. This average spectrum is well fitted by a power law with r ,~ 0.51 ± 0.11 plus a cutoff energy at 128.6 ± 17.2 keV. The hard X-ray flux of the source from 20-150 keV showed no significant variations （within 20%） from 2003- 2011. The spectral profiles have some variability over the nine years such that the photon index varies from 0.3-1.5 and the cutoff energies from 110-250 keV. The de- tection of the high energy cutoff around 130 keV shows some constraints on the radia- tion mechanisms of magnetars and possibly probes the differences between magnetar and accretion models for this special class of neutron stars. Future HXMTobservations could provide stronger constraints on the hard X-ray spectral properties of this source and other magnetar candidates.
基金supported by the National Natural Science Foundation of China(grant Nos.12203013,12273005,and U1938201)China Manned Spaced Project(CMS-CSST-2021-B11)the Guangxi Science Foundation(grant Nos.AD22035171 and 2023GXNSFBA026030)。
文摘The detection of quasi-periodic oscillations(QPOs)in magnetar giant flares(GFs)has brought a new perspective to studies of the mechanism of magnetar bursts.Due to the scarcity of GFs,searching for QPOs in magnetar short bursts is reasonable.Here we report the detection of a narrow QPO at approximately 110 Hz and a wide QPO at approximately 60 Hz in the short magnetar burst SGR 150228213,with a confidence level of 3.35σ.This burst was initially attributed to 4U 0142+61 by Fermi/GBM on location,but we have not detected such QPOs in other bursts from this magnetar.We also found that there was a repeating fast radio burst associated with SGR 150228213 on location.Finally,we discuss the possible origins of SGR 150228213.
