Nanda Rea. XMM-Newton reveals magnetars magnetospheric densities. University of Amsterdam Astronomical Institute Anton Pannekoek NWO Veni Fellow

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1 XMM-Newton reveals magnetars magnetospheric densities Nanda Rea University of Amsterdam Astronomical Institute Anton Pannekoek NWO Veni Fellow In collaboration with : Silvia Zane Roberto Turolla Maxim Lyutikov Diego Gotz Luciano Nobili

2 Introduction: Magnetars bright X-ray pulsars Lx ~ erg/s rotating with periods of 2-12s large period derivatives glitches bursts on many timescales (ms to 100s) transient outbursts radio pulsars only during outbursts (review: Woods & Thompson 2006, Cambridge Press; Mereghetti 2008, A&AR)

3 Introduction: Magnetars Hard X-rays soft X-rays Gamma-rays IR and optical Radio

4 Introduction: Magnetars RXS J XTE (Rea et al. 2005, MNRAS; Gotthelf et al. 2004, ApJ)

5 Main point: closed field lines in NS magnetospheres are not dead. Populated by hot, highly over-dense plasma, n >> ngj (e.g. Thompson, Lyutikov & Kulkarni 2002; Liutykov & Gavriil 2006) Twisted magnetospheres are filled with plasma which may modify radiation properties. # " RCS ~ R & L % (" T ~ 10 5 " T $ ' at 1 kev with " B R L ~ 8R NS NS $ # r e B crit 1/ 3 % " 1keV ' $ & # h( B % ' & 1/ 3

6 ω 0 =ω B n + ω 0 n- Δr ~r β T /3 <<r How does a warm plasma in the magnetosphere modify the emergent spectra?

7 3 free parameters, same as for the empirical blackbody+powerlaw model: Flux same statistical significance Optical depth $ e dz. " RCS = # RCS n (1-10) Energy (kev) - 10 Electron thermal velocity " T ( ) Surface Temperature (kev) kt ( ) Flux 1 - Energy (kev) - 10 Rea, Zane, Turolla, Lyutikov & Gotz 2008, ApJ submitted, arxiv: v2

8 The Magnetar Sample Hosts P (s) B (10 14 G) kt(kev) / Γ L (10 33 erg/s) (0.2-10keV) comments 4U / hard X RXS J / hard X 1E Kes / hard X 1E CTB / ~ transient/hard X CXO J in SMC / E / ~ transient 1E / transient/radio XTE / transient/radio CXO in Wes / transient AX J G / transient SGR OB / GF/hardX SGR OB / GF/hardX/outburst SGR in LMC / GF/? SGR G ? 6.4? - / outburst

9 AXPs with hard X-ray emission 4U U Flux BB+PL+PL 1 - Energy (kev) RXS J RXS J RCS+PL BB+PL+PL RCS+PL 1E E BB+PL RCS+PL Rea, Zane, Turolla, Lyutikov & Gotz 2008, ApJ submitted, arxiv: v2

10 Transient AXPs 1E CXO BB+PL Flux RCS BB+PL RCS 1 - Energy (kev) E XTE BB+PL BB+PL RCS RCS Rea, Zane, Turolla, Lyutikov & Gotz 2008, ApJ submitted, arxiv: v2

11 SGRs with hard X-ray emission SGR SGR Flux SGR BB+PL 1 - Energy (kev) BB+PL SGR Flux RCS+PL RCS+PL 1 - Energy (kev) - 10 Rea, Zane, Turolla, Lyutikov & Gotz 2008, ApJ submitted, arxiv: v2

12 kt (kev) L 1-10keV (10 34 erg/s) Rea, Zane, Turolla, Lyutikov & Gotz 2008, ApJ submitted, arxiv: v2

13 τ res L 1-10keV (10 34 erg/s) Magnetospheric e- density of n~1.5x10 13 cm -3 = 10 3 n GJ Rea, Zane, Turolla, Lyutikov & Gotz 2008, ApJ submitted, arxiv: v2

14 3D Monte Carlo RCS: applications (preliminary) 1E RCS 3D kt ~ kev β bulk ~ Δφ ~ E Magnetospheric e- density consistent with the simplified 1D model, hence being ~ 10 3 n GJ 1E RCS 3D RCS 3D +PL (Nobili, Turolla & Zane 2008, MNRAS; Rea et al. 2008, in prep; Albano et al. 2008, in prep)

15 Conclusions done We built an analytical model to threat resonant cyclotron scattering Implementing it in XSPEC for real data fitting Resonant cyclotron scattering reproduces all magnetar spectra This model has a clear physical motivation, unlike BB+PL models We could derive for the first time the magnetospheric density of magnetars Much larger than for normal pulsars, as indeed predicted by the theory Absorption values now matches what has been derived from single edge fitting The BB+PL model overestimates the N H in progress More advanced 3D Monte-Carlo models for magnetar magnetospheres Full 3-D magnetosphere (Fernandez & Thompson 2007; Nobili, Turolla & Zane 2008) Application to the data (Rea et al. in prep; Albano et al. in prep)