1. The hard X-ray spectrum of Pulsar Wind Nebulae Data-models comparison in the Simbol-X era F. Bocchino, INAF Osservatorio Astronomico di Palermo with contributions of R. Bandiera (INAF-OAA), L. Del Zanna (UNIFI), D. Volpi (UNIFI), G. Cusumano (INAF-IASF Pa)

2. Introduction What is a PWN...

3. Introduction The mechanism which bring particles and fields to the outer edge of the nebulae is still under investigation It's like finding the transmission lines between the power plant and the light bulb. (J. Hester, Arizona Univ.)

4. Examples of PWNe 1 The Crab Nebula SN1054 L X =2.4 10 37 erg/s Distance 2 kpc Calib. source

5. Examples of PWNe 1 The Vela PWN Age 11 kyr L X =6 10 33 erg s D = 0.2 kpc

6. Symbol-X and PWNe Doing Chandra-like imaging is hopeless Low bkg will make Symbol-X extremely competitive w.r.t. current non-imaging hard X-ray instruments Easy detection of PWNe above 10 keV in reasonable single- pointing exposure time Recent advances in theoretical modeling of PWNe have pointed out the importance of the study of the shape of PWN integrated X-ray spectrum

7. Spectra of PWNe Zero order approximation Synchrotron aging of a constantly injected power-law population (Ginzburg & Syrovatskii 1965)

8. Spectra of PWNe classical model (Pacini & Salvati 73) Synchrotron aging of a power-law population and decreasing injection Frequency

9. Spectra of PWNe Modern approaches based on inhomogeneous models MHD simulations, calculations of synchrotron emissivities (Del Zanna et al. 2006)

10. Spectra of PWNe Alternative views Diffusive synchrotron radiation from PWNe (Fleishman & Bietenholtz 2007) Aimed to overcome difficulties of classical approaches to non-Crab like PWNe

11. X-ray spectra of PWNe XMM-Newton 30 ks INTEGRAL/IBIS, 439 SCWs in 2003-2004, 1 Ms f X = 0.4 mCrab Single power-law NH=2.5+/-0.1 10 22 cm -2 = 1.74 +/- 0.06

12. Data sensitivity to spectral breaks in hard X-ray

13. VELA: Mangano et al (2006), BeppoSAX MECS+PDS CRAB1: de Jager et al. (1996), balloon-borne experiments CRAB2: Massaro et al. (2000) BeppoSAX NFI+HP+PDS

14. Data sensitivity to spectral breaks in hard X-ray VELA: Mangano et al (2006), BeppoSAX MECS+PDS CRAB1: de Jager et al. (1996), balloon-borne experiments CRAB2: Massaro et al. (2000) BeppoSAX NFI+HP+PDS Black: XMM 30 ks + ISGRI 1 Ms

15. VELA: Mangano et al (2006), BeppoSAX MECS+PDS CRAB1: de Jager et al. (1996), balloon-borne experiments CRAB2: Massaro et al. (2000) BeppoSAX NFI+HP+PDS Data sensitivity to spectral breaks in hard X-ray Black: XMM 30 ks + ISGRI 1 Ms RED: Suzaku 300 ks std. bkg

16. VELA: Mangano et al (2006), BeppoSAX MECS+PDS CRAB1: de Jager et al. (1996), balloon-borne experiments CRAB2: Massaro et al. (2000) BeppoSAX NFI+HP+PDS Data sensitivity to spectral breaks in hard X-ray Black: XMM 30 ks + ISGRI 1 Ms RED: Suzaku 300 ks std. Bkg Green: Simbol-X 100 ks

17. Data-model comparison in the Simbol-X era Simulated synchrotron emission from PWNe (Del Zanna et al. 2006) run A: =0.025, nearly ideal case for Crab run B: =0.1 large equatorial unmagnetized region equatorpole

18. Data-model comparison in the Simbol-X era: the Crab Only the nebular emission is considered VELA: Mangano et al 06 (obs) CRAB1: de Jager et al. 1996 (obs) CRAB2: Massaro et al 2000 (obs) LDZ06: Del Zanna et al 2006 (models)

19. Data-model comparison in the Simbol-X era: the Crab Only the nebular emission is considered VELA: Mangano et al 06 (obs) CRAB1: de Jager et al. 1996 (obs) CRAB2: Massaro et al 2000 (obs) LDZ06: Del Zanna et al 2006 (model) Black: Simbol-X 100 ks simulated spectrum

20. Data-model comparison in the Simbol-X era: 3C 58 Prototype of non-Crab like PWNe Diffusive synchrotron radiation from PWNe (Fleishmann & Bietenholtz 2007) seems to overcome the difficulty of low frequency and large change of slope of the break in the radio band What about in the X-ray band?

21. Data-model comparison in the Simbol-X era: 3C 58 DSR 3c58: Diffusive synchrotron radiation model of Fleishmann & Bietenholz (2007) tailored to 3c58 broad band spectrum

22. Data-model comparison in the Simbol-X era: 3C 58 Black solid: XMM 30 ks DSR 3c58: Diffusive synchrotron radiation model of Fleishmann & Bietenholz (2007) tailored to 3c58 broad band spectrum

23. Data-model comparison in the Simbol-X era: 3C 58 Black solid: XMM 30 ks Red solid: Simbol-X 100 ks DSR 3c58: Diffusive synchrotron radiation model of Fleishmann & Bietenholz (2007) tailored to 3c58 broad band spectrum

24. Conclusions The shape of the hard X-ray spectrum of Pulsar Wind Nebulae is directly related to the distribution of B and e- in the source Current measurements are just enough to provide some diagnostics for the brightest objects (Crab and Vela) Simbol-X may provide an order of magnitude improvement in the comparison between model and observations for these bright sources Other bright PWNe (G21.5-0.9, 3C58) are hardly detected by non- imaging hard X-ray instruments. Simbol-X will provide THE unique opportunity to study the spectrum above 5-10 keV.