1. To test AXP/SGR models with eXTP NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu Renxin Xu ( 徐仁新 ) School of Physics, Peking University ( ) eXTP workshop at IHEP Oct. 26, 2015; Beijing Collaborators : Zhaosheng Li, Shi Dai, Hao Tong, …

2. Summary What AXP/SGRs are: a challenge AXP/SGR models To test the models with eXTP Conclusions NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

3. Summary What AXP/SGRs are: a challenge AXP/SGR models To test the models with eXTP Conclusions NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

4. What AXP/SGRs are: a challenge AXP = Anomalous X-ray Pulsar, SGR = Soft Gamma-ray Repeater Tong & Xu (2011) AXP/SGRs XDINSs RRATs radio loud AXP/SGR  Energy budget problem ! NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu  Isolated  L x ~ 10 34-36 erg/s >> I   Short bursts (~0.1s), flares (~10s, even giant flares ~ 10 2 s with ~ 10 47 erg!) and outburst (~10 2 days).  How can a compact star release so huge energy?

5. What AXP/SGRs are: a challenge What could be the free energy radiated? NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu If the compact star is an NS, as popularly believed, … (Heiselberg, 2000) a conventional neutron star = solid crust + fluid inside an analogy: a raw egg No significant free energy, but … B-filed speculated? magnetar model

6. “… The successful use of Yang-Mills theory to describe the strong interactions of elementary particles depends on a subtle quantum mechanical property called the "mass gap": the quantum particles have positive masses, even though the classical waves travel at the speed of light. …” Is the compact star really NS? This is surely unsolved, being related to one of the Millennium Problems. As in the case of Navier-Stokes Equation, we do have a framework for strong interaction, the QCD Lagrangian: although asymptotic, but non-perturbative in low-E scale. Mathematical difficulty of NQCD provides opportunity for eXTP to drop hints about NQCD! Note: Energy scale ~ 0.4 GeV < 1 GeV (~0.5 fm) pc ~  c ~ 200 MeV·fm NQCD! Unfortunately and fortunately, the state of cold matter at around nuclear density of non-perturbative QCD!

7. We are developing quark-cluster model… proton neutron f = 2f = 3 u u d u d d u s d d u s “boiled egg”: condensed matter of quark-clusters! ~ fm~ 10 km Quantum gas/liquid?Classical solid?! NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu What AXP/SGRs are: a challenge cluster

8. Different models of pulsar’s nature in the market conventional Neutron Star light flavour symmetry: Strange Star What AXP/SGRs are: a challenge NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

9. Summary What AXP/SGRs are: a challenge AXP/SGR models To test the models with eXTP Conclusions NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

10. AXP/SGR models NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu Two types of AXP/SGR models magnetar quark- cluster star free energy B-field decay by reconnection B-field configuration evolutional behavior grav./elastic energy release by AISq super strong B-toroidal necessary normal and ordered B- field special birth with P initial < 3 ms standard birth but different nurture and nature

11. AXP/SGR models NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu What is AISq? Accretion-Induced Star-quake! Part persistent X- rays + propeller torque (high P) Bursts or flares + Glitches.

12. Gravitational/elastic free energy?  quake-induced fireballs for AXPs/SGRs R RR for M ~ M ⊙ Magnetar vs. Quark-cluster star AXP/SGR models NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

13. Gravitational/elastic free energy? P (1+  )P  E could be as high as ~10 48 erg if  = 10 -4 ! Xu et al. (2006) AXP/SGR models NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu Static and spherically symmetric solution of solid body?

14. Summary What AXP/SGRs are: a challenge AXP/SGR models To test the models with eXTP Conclusions NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

15. X-ray timing is essential for…  {P, Pdot}  evolution or B-field  pulse profile, change  emission mechanism  glitch, precession, noise  global structure  binary, dynamics (AXP/SGR in binary?) To test the models with eXTP X-ray polarization for testing magnetar model  pln pulse-profile  torsional B-field predicted  pln percentage  QED effect predicted NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

16. eXTP timing to know small both glitch & burst To test the models with eXTP NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu Small glitch small outburst 4U 0142+61 XTP eXTP

17. eXTP timing to discover precession? To test the models with eXTP NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu XTP(LFA+HFA) Exposure eXTP Thompson et al. (2000) Free precession period:

18. To test the models with eXTP To probe magnetar multipolar field configuration Radio pulsars: dipolarMagnetars: multipolar NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

19. RVM for radio pulsars, what for magnetars? Magnetar v.s. Quark-cluster star: modeling and simulating necessary! Johnston et al. (2001) Radhakrishnan & Cooke (1969) “S” shape P.A. L I V To test the models with eXTP NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

20. QED effect for polarized X-ray emission To test the models with eXTP NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu The thermal X-rays should be linearly polarized with percentage P L > 20%!

21. Summary What AXP/SGRs are: a challenge AXP/SGR models To test the models with eXTP Conclusions NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu

22. Conclusions eXTP may help to solve one of Millen. Probl. X-ray timing and polarization telescope ToA Abundant information about global stellar structure Burst behavior Energy budget and Explosive mechanism Polarization Probing multipolar B-field, radiative mechanism To understand EoS of cold dense matter at supra-nuclear density, relevant to fundamental color interaction NSs & magnetarshttp://www.phy.pku.edu.cn/~xurenxin/ R. X. Xu