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A MULTI-WAVELENGTH STUDY OF PSR J1119-6127 AFTER 2016 OUTBURST

A MULTI-WAVELENGTH STUDY OF PSR J1119-6127 AFTER 2016 OUTBURST. Reporter: Huihui Wang 王 惠惠 Supervisor: Jumpei Takata Huazhong University of Science and Technology. collaborator ： J . Takata (HUST, China) L.C.C. Lin , K.L. Li (UNIST, Korea)

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A MULTI-WAVELENGTH STUDY OF PSR J1119-6127 AFTER 2016 OUTBURST

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  1. A MULTI-WAVELENGTH STUDY OF PSR J1119-6127 AFTER 2016 OUTBURST Reporter: HuihuiWang 王 惠惠 Supervisor:JumpeiTakata Huazhong University of Science and Technology collaborator： J. Takata (HUST, China) L.C.C. Lin, K.L. Li (UNIST,Korea) C.-P. Hu (UniversityofKyoto,Japan) S. Dai (CSIRO, Australia)M. Kerr (Space Science Division, Washington) X.Hou (YunnanObservatory, China)

  2. Outline • Introduction • Dataanalysis • Theoretical interpretation • Summary HUST

  3. 1. Introduction PSRJ1119-6127 • Spinperiod: • Surface magnetic field : • -- High-B radio/gamma-ray pulsar • Spin-downpower: • Characteristic age : • Glitching pulsar • - Aug. 1999, Oct. 2004, May 2007, July 2016 • (this work)

  4. 1. Introduction 2016 X-ray burst and glitch • X-ray burst triggered by Fermi/GBM triggered on 2016 July 27 • Duration of 0.040s 。 • Large glitch (Archibald et al 2016) (Gogus et al. 2016)

  5. 1. Introduction X-ray emission after the outburst • Hard X-ray emission (>10keV) were clearly observed with a non-thermal component. • - Photon index 0.5-1, similar to magnetar’s hard X-ray emission. • X-ray luminosity (~1035erg/s) is about 17% of the spin down power Magnetic powered activities (magnetar-like process) (Archibaldetal.2016) PSR J1119-6127 will the first rotation-poweredradio/gamma-ray pulsar that shows magnetar-likeactivities.

  6. 1. Introduction Radio and spin down rate evolution • Radio flux/spin down rate increased until about one month after the X-ray outburst. • On 30/Aug. 2016, they started to recover toward the values before the outburst. • The recovery would be ended at end of 2016. Radio flux Global structure of the magnetosphere would evolve after the X-ray outburst. Dai.etal(2018) HUST

  7. Purpose of this works Investigate and study the evolution of the magnetosphere after X-ray outburst with the multi-wavelength observations. • Joint phase-resolved spectrum for XMM/Nustar data. • Relation between X-ray and radio peak. • GeV emission properties • - Searching pulsed signal after the X-ray outburst • Theoretical interpretation

  8. 2. Data analysis XMM/Nustar:Jointphase-resolvespectra Nustar’s X-ray light curve XMM’s X-ray light curve 3-78KeV 0.5-10KeV On-phase Off-phase • In August data, the on-phase and off-phase emissions both require the power law component with a photon index 0.5-1. • No pulsed signal at >10keV was detected in August/Dec data. •  Hard X-ray emission might be isotropic. HUST

  9. 2. Data analysis X-ray/radio pulse correlation Before outburst Afterburst (heated polar cap) Aug. 6 Aug. 15 Dec. 14/15 Aug. 30 Ng et al. (2012) • Peak shift after the outburst. •  New X-ray region and/or change of the radio beam. • No clear shift in Dec. 2016. • The magnetic field structure probably recovered to previous state. • ( Observed X-ray luminosity was still ~10 times larger). HUST

  10. 2. Data analysis GeV emission Blue: Pre-outburst Outburst/ Relaxation Pre-burst Post-relaxation Red: Relaxation Black: post-relaxation Outburst • GeV emission was suppressed after the X-ray outburst. • Spectral properties after Dec. 2016 (post-relaxation) is consistent with pre-bust stage.

  11. 2. Data analysis Pulsed emission • Single pulsed profile was confirmed in the data after Dec. 2016 (MJD 56980-5748, post relaxation stage). • It is similar to the profile of Pre-outburst. • All GeV emission properties after Dec. 2016 are consistent with those of pre-outburst stage.

  12. 3. Discussion Untwisting magnetosphere • Glitch induced twist of the closed magnetic field lines (Beloborodov 2009). • Magnetar-like process. • Explaining X-ray evolution for magnetar XTE J1810-197 • The twisted energy is released by joule heating (untwisting). • Acceleration of the electron/positron pairs. • Resonant inverse Compton scattering. • Non-thermal X-ray component after outburst. • Bombardment of pairs on the stellar surface. • Heated polar cap emission. Glitch (Thompson et al. 2002)

  13. 3. Discussion Untwisting magnetosphere Fitting the X-ray evolution with model Observations: • X-ray emission decreased with time after the outburst. • Radio/X-ray/gamma-ray emission and timing properties suggest the magnetosphere was relaxed to the previous stage with a time scale ~0.5 year. Line : model prediction X-ray luminosity [erg/s] Initial twist angle : Time after outburst [s] Polar angle of the twisted field line region :

  14. 3. Discussion Untwisting magnetosphere • In August 2016, • Why did the radio flux increase ? •  new radio emission region was formed on twisted and/or new opened field lines. • Why did the spin down rate increase ? • The current along the twisted magnetic field  lines creates a toroidal current component, Iφ, which createsadditionaldipolemoment. • . • Untwisting of the magnetosphere effectively started at around 30/August 2016, and it was completed at end of 2016.

  15. Summary • PSR J1119-6127 will be the first radio/gamma-rayrotationpowered pulsar that shows the magnetar-like outburst activity. • The untwisting magnetosphere model can explain the evolutions of the multi-wavelength emission and spin-down rate after the X-ray outburst : (i) Hard X-ray emission with a photon index 0.5-1 (probably RCS process) (ii) Clear shift between the X-ray and radio pulse in Aug./2016 data, but no clear shift in Dec./2016 data. (ii) Radio flux, gamma-ray properties and spin down rate recovered to the previous stage with a time scale of ~0.5 years.

  16. Thankyouforlistening

  17. 2. Data analysis Two Blackbody plus one powerlaw model

  18. Gamma-raymodel • The drop of GeV flux can be explained by the change of the emission size at the outburst. • GeV gamma-rays from the outer gap (Cheng et al. 1986) • Theradiationpowerofthegapisontheorderof: k.Scheng1986 where fgap represents a fraction of the open magnetic field lines that penetrate the outer gap. HUST

  19. Gamma-raytheory gamma-rayemissionbycurvatureradiation • The gap fraction is determined by the condition of the photon-photon pair creation process • Where the energy of x-ray canbeget from the observed data , • the flux is proportional tofgap, HUST

  20. Gammarayflux • We expect that gamma-ray flux after the outburst about two order of magnitude smaller than that before the outburst. • At ~6 months after the outburst, the thermal emission is quickly decreasing, which causes the recovery of the GeV emission. HUST

  21. 3. Discussion • Why did the radio flux increase ?

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