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
We investigate the statistical effects of non-discrete timing irregularities on observed radio pul- sar braking indices using correlations between the second derivative of the measured anomalous frequency （vobs） and...We investigate the statistical effects of non-discrete timing irregularities on observed radio pul- sar braking indices using correlations between the second derivative of the measured anomalous frequency （vobs） and some parameters that have been widely used to quantify pulsar timing fluctuations （the timing activity parameter （A）, the amount of timing fluctuations absorbed by the cubic term （crR23） and a measure of pulsar rotational stability （δz）） in a large sample of 366 Jodrell Bank Observatory radio pulsars. The result demonstrates that anomalous braking indices are largely artifacts produced by aggregations of fluc- tuations that occur within or outside the pulsar system. For a subsample of 223 normal radio pulsars whose observed timing activity appeared consistent with instabilities in rotation of the underlying neutron stars （or timing noise） over timescales of - 10 - 40 yr,/vobs / strongly correlates （with correlation coefficient /r/ - 0.80 - 0.90） with the pulsar timing activity parameters and spin-down properties. On the other hand, no meaningful correlations （r 〈 0.3） were found between/）obs and the timing activity diagnostics and spin- down parameters in the remaining 143 objects, whose timing activity appears significantly dominated by white noise fluctuations. The current result can be better understood if the timing noise in isolated pulsars originates from intrinsic spin-down processes of the underlying neutron stars, but white noise fluctuations largely arise from processes external to the pulsar system.展开更多
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.
文摘We investigate the statistical effects of non-discrete timing irregularities on observed radio pul- sar braking indices using correlations between the second derivative of the measured anomalous frequency （vobs） and some parameters that have been widely used to quantify pulsar timing fluctuations （the timing activity parameter （A）, the amount of timing fluctuations absorbed by the cubic term （crR23） and a measure of pulsar rotational stability （δz）） in a large sample of 366 Jodrell Bank Observatory radio pulsars. The result demonstrates that anomalous braking indices are largely artifacts produced by aggregations of fluc- tuations that occur within or outside the pulsar system. For a subsample of 223 normal radio pulsars whose observed timing activity appeared consistent with instabilities in rotation of the underlying neutron stars （or timing noise） over timescales of - 10 - 40 yr,/vobs / strongly correlates （with correlation coefficient /r/ - 0.80 - 0.90） with the pulsar timing activity parameters and spin-down properties. On the other hand, no meaningful correlations （r 〈 0.3） were found between/）obs and the timing activity diagnostics and spin- down parameters in the remaining 143 objects, whose timing activity appears significantly dominated by white noise fluctuations. The current result can be better understood if the timing noise in isolated pulsars originates from intrinsic spin-down processes of the underlying neutron stars, but white noise fluctuations largely arise from processes external to the pulsar system.
