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IS PULSAR B0628-28 REALLY AN EXCEPTION?

IS PULSAR B0628-28 REALLY AN EXCEPTION?. Cuilan Qiao Mentor:Pro. Xiangdong Li Dec.7, 2005. OUTLINE. 1 Introduction 2 Data analysis for spin-powered pulsars 3 Theoretic discussion 4 Conclusion. 1 Introduction. Observation of pulsar B6028-28 Chandra:

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IS PULSAR B0628-28 REALLY AN EXCEPTION?

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  1. IS PULSAR B0628-28 REALLY AN EXCEPTION? Cuilan Qiao Mentor:Pro. Xiangdong Li Dec.7, 2005

  2. OUTLINE • 1 Introduction • 2 Data analysis for spin-powered pulsars • 3 Theoretic discussion • 4 Conclusion

  3. 1 Introduction • Observation of pulsar B6028-28 Chandra: ► Was observed twice:first on Nov.4,2001 and again on 2002 Mar.25 for 2000 and 17000s respectively;1.141s exposures. ► position is XMM-Newton: ► Was observed on 2004 Feb. 28 for a total on time of 48ks;47ks exposures. ► position is

  4. Properties of pulsar B6028-28 ► The longest period radio pulsar detected in X-rays (P=1244ms). ► The Chandra data yielded a luminosity 2 orders of magnitude greater than what is expected for a spin-powered pulsar(logLx=30.34). ► From Tepedelenlioglu et. al ,APJ astro-ph/0505461

  5. Old pulsars • Other 41 spin-powered pulsars(Possentiet al.2002) MSPs Giminga-like

  6. Vela-like Crab-like

  7. 2 Data analysis for spin-powered pulsars • Clustering analysis-with Nearest Neighbor method in matlab ► Zscore-----data standardization ► Pdist-----calculate space between two objects by Euclidean distance ► Squareform-----Euclidean distance matrix ► Linkage-----nearest neighbor method ► cluster-----cluster data ► find----- find elements of every group ► Dendrogram-----draw clustering graph

  8. 42 spin-powered pulsars clustering diagrams • clustering result with logτ and logLx

  9. 2 clustering result with logdP/dt、logτ and logLx

  10. clustering result with logP、logdP/dt、logτand logLx

  11. clustering result with logP、logdP/dt、logτ、logLsd and logLx

  12. clustering result with logP and logLx

  13. clustering result with logLsd and logLx

  14. Fitting • 42 spin-powered pulsars fitting graphes with errorbars logLx~logτ B0628-28

  15. B0628-28 logLx~logLsd

  16. 42 spin-powered pulsars fitting parameter

  17. 3 Theoretic discussion • Model ---a one-zone shocked wind model (Chevalier,2000) • The central pulsar generates a highly relativistic,particle-dominated wind that passes through the medium in the supernova remant,forming a shock front. The electrons and positrons in the wind acruire a power-law energy spectrum in the shock front and radiate synchrotron emission in the sownstream region. The basic simplification is that the emitting region can he treated as one zone One-zone model that does not attemp to account for the spatial structrue of the nebulae.

  18. 3 Theoretic discussion

  19. 4 Conclusion • 42 spin-powered pulsars can be grouped into 2 groups; • Lx~τ-2,Lx~Lsd; • Pulsar B5028-28 is under the groups of spin-powered pulsars.

  20. Thanks!

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