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تسجيل مستخدم جديدNo detectable radio emission from the magnetar-like pulsar in Kes 75
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The rotation-powered pulsar PSR J1846-0258 in the supernova remnant Kes 75 was recently shown to have exhibited magnetar-like X-ray bursts in mid-2006. Radio emission has not yet been observed from this source, but other magnetar-like sources have exhibited transient radio emission following X-ray bursts. We report on a deep 1.9 GHz radio observation of PSR J1846-0258 with the 100-m Green Bank Telescope in late 2007 designed to search for radio pulsations or bursts from this target. We have also analyzed three shorter serendipitous 1.4 GHz radio observations of the source taken with the 64-m Parkes telescope during the 2006 bursting period. We detected no radio emission from PSR J1846-0258 in either the Green Bank or Parkes datasets. We place an upper limit of 4.9 mu Jy on coherent pulsed emission from PSR J1846-0258 based on the 2007 November 2 observation, and an upper limit of 27 mu Jy around the time of the X-ray bursts. Serendipitously, we observed radio pulses from the nearby RRAT J1846-02, and place a 3sigma confidence level upper limit on its period derivative of 1.7 * 10^{-13}, implying its surface dipole magnetic field is less than 2.6 * 10^{13} G.
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We report detection of magnetar-like X-ray bursts from the young pulsar PSR J1846-0258, at the center of the supernova remnant Kes 75. This pulsar, long thought to be rotation-powered, has an inferred surface dipolar magnetic field of 4.9x10^13 G, hi
gher than those of the vast majority of rotation-powered pulsars, but lower than those of the ~12 previously identified magnetars. The bursts were accompanied by a sudden flux increase and an unprecedented change in timing behavior. These phenomena lower the magnetic and rotational thresholds associated with magnetar-like behavior, and suggest that in neutron stars there exists a continuum of magnetic activity that increases with inferred magnetic field strength.
Rotation-powered pulsars and magnetars are two different observational manifestations of neutron stars: rotation powered pulsars are rapidly spinning objects that are mostly observed as pulsating radio sources, while magnetars, neutron stars with the
highest known magnetic fields, often emit short-duration X-ray bursts. Here we report simultaneous observations of the high-magnetic-field radio pulsar PSR J1119-6127 at X-ray, with XMM-Newton & NuSTAR, and at radio energies with Parkes radio telescope, during a period of magnetar-like bursts. The rotationally powered radio emission shuts off coincident with the occurrence of multiple X-ray bursts, and recovers on a time scale of ~70 seconds. These observations of related radio and X-ray phenomena further solidify the connection between radio pulsars and magnetars, and suggest that the pair plasma produced in bursts can disrupt the acceleration mechanism of radio emitting particles.
Radio pulsars are believed to have their emission powered by the loss of rotational kinetic energy. By contrast, magnetars show intense X-ray and gamma-ray radiation whose luminosity greatly exceeds that due to spin-down and is believed to be powered
by intense internal magnetic fields. A basic prediction of this picture is that radio pulsars of high magnetic field should show magnetar-like emission. Here we report on a magnetar-like X-ray outburst from the radio pulsar PSR J1119-6127, heralded by two short bright X-ray bursts on 2016 July 27 and 28 (Kennea et al. 2016; Younes et al. 2016). Using Target-of-Opportunity data from the Swift X-ray Telescope and NuSTAR, we show that this pulsars flux has brightened by a factor of > 160 in the 0.5-10 keV band, and its previously soft X-ray spectrum has undergone a strong hardening, with strong pulsations appearing for the first time above 2.5 keV, with phase-averaged emission detectable up to 25 keV. By comparing Swift-XRT and NuSTAR timing data with a pre-outburst ephemeris derived from Fermi Large Area Telescope data, we find that the source has contemporaneously undergone a large spin-up glitch of amplitude df/f = 5.74(8) E-6. The collection of phenomena observed thus far in this outburst strongly mirrors those in most magnetar outbursts and provides an unambiguous connection between the radio pulsar and magnetar populations.
PSR J1846-0258 is a radio-quiet rotation-powered pulsar at the center of Supernova remnant Kes 75. It is the youngest pulsar (~723 year) of all known pulsars and slows down very predictably since its discovery in 2000. Till June 7, 2006 very stable b
ehavior has been displayed both in the temporal and spectral domains with pulsed emission detectable by INTEGRAL IBIS ISGRI and RXTE HEXTE up to ~150 keV. Then, a dramatic brightening was detected of the pulsar during June 7-12, 2006 Chandra observations of Kes 75. This radiative event, lasting for ~55 days, was accompanied by a huge timing glitch, reported on for the first in present work. Moreover, several short magnetar-like bursts were discovered. In this work not only the time-averaged pre-outburst X-ray/soft gamma-ray characteristics are discussed in detail, but also the spectral evolution during the outburst and its relaxation phase are addressed using RXTE PCA and HEXTE and INTEGRAL IBIS ISGRI data.
We report new Chandra X-ray observations of the shell supernova remnant (SNR) Kes 75 (G29.7-0.3) containing a pulsar and pulsar-wind nebula (PWN). Expansion of the PWN is apparent across the four epochs, 2000, 2006, 2009, and 2016. We find an expansi
on rate between 2000 and 2016 of the NW edge of the PWN of 0.249% +/- 0.023% yr^{-1}, for an expansion age R/(dR/dt) of 400 +/- 40 years and an expansion velocity of about 1000 km s^{-1}. We suggest that the PWN is expanding into an asymmetric nickel bubble in a conventional Type IIP supernova. Some acceleration of the PWN expansion is likely, giving a true age of 480 +/- 50 years. The pulsars birth luminosity was larger than the current value by a factor of 3 -- 8, while the initial period was within a factor of 2 of its current value. We confirm directly that Kes 75 contains the youngest known PWN, and hence youngest known pulsar. The pulsar PSR J1846-0258 has a spindown-inferred magnetic field of 5 x 10^{13} G; in 2006 it emitted five magnetar-like short X-ray bursts, but its spindown luminosity has not changed significantly. However, the flux of the PWN has decreased by about 10% between 2009 and 2016, almost entirely in the northern half. A bright knot has declined by 30% since 2006. During this time, the photon indices of the power-law models did not change. This flux change is too rapid to be due to normal PWN evolution in one-zone models.
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