The hard Xray spectrum of Pulsar Wind Nebulae

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)

Introduction What is a PWN. . .

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. )

Examples of PWNe 1’ The Crab Nebula SN 1054 LX=2. 4 1037 erg/s Distance 2 kpc Calib. source

Examples of PWNe 1’ The Vela PWN Age 11 kyr LX=6 1033 er D = 0. 2 kpc

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 ke. V in reasonable singlepointing 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

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

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

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

X-ray spectra of PWNe XMM-Newton 30 ks INTEGRAL/IBIS, 439 SCWs in 2003 -2004, 1 Ms f. X = 0. 4 m. Crab Single power-law NH=2. 5+/-0. 1 1022 cm-2 g = 1. 74 +/- 0. 06

Data sensitivity to spectral breaks in hard X-ray

Data sensitivity to spectral breaks in hard X-ray VELA: Mangano et al (2006), Beppo. SAX MECS+PDS CRAB 1: de Jager et al. (1996), balloon-borne experiments CRAB 2: Massaro et al. (2000) Beppo. SAX NFI+HP+PDS

Data sensitivity to spectral breaks in hard X-ray Black: XMM 30 ks + ISGRI 1 Ms VELA: Mangano et al (2006), Beppo. SAX MECS+PDS CRAB 1: de Jager et al. (1996), balloon-borne experiments CRAB 2: Massaro et al. (2000) Beppo. SAX 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 VELA: Mangano et al (2006), Beppo. SAX MECS+PDS CRAB 1: de Jager et al. (1996), balloon-borne experiments CRAB 2: Massaro et al. (2000) Beppo. SAX 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 VELA: Mangano et al (2006), Beppo. SAX MECS+PDS CRAB 1: de Jager et al. (1996), balloon-borne experiments CRAB 2: Massaro et al. (2000) Beppo. SAX NFI+HP+PDS

Data-model comparison in the Simbol-X era Simulated synchrotron emission from PWNe (Del Zanna et al. 2006) run A: s=0. 025, nearly ideal case for Crab run B: s=0. 1 large equatorial unmagnetized region pole equator pole

Data-model comparison in the Simbol-X era: the Crab Only the nebular emission is considered VELA: Mangano et al 06 (obs) CRAB 1: de Jager et al. 1996 (obs) CRAB 2: Massaro et al 2000 (obs) LDZ 06: Del Zanna et al 2006 (models)

Data-model comparison in the Simbol-X era: the Crab Black: Simbol-X 100 ks simulated spectrum Only the nebular emission is considered VELA: Mangano et al 06 (obs) CRAB 1: de Jager et al. 1996 (obs) CRAB 2: Massaro et al 2000 (obs) LDZ 06: Del Zanna et al 2006 (model)

Data-model comparison in the Simbol-X era: 3 C 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?

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

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

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

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 (G 21. 5 -0. 9, 3 C 58) are hardly detected by nonimaging hard X-ray instruments. Simbol-X will provide THE unique opportunity to study the spectrum above 5 -10 ke. V.