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Supernova Remnants and Pulsar Wind Nebulae in the Chandra Era July 8-10 2009, Boston, USA X-ray signature of shock modification in SN 1006 Marco Miceli Università di Palermo, INAF - Osservatorio Astronomico di Palermo Collaborators:
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Supernova Remnants and Pulsar Wind Nebulae in the Chandra Era July 8-10 2009, Boston, USA X-ray signature of shock modification in SN 1006 Marco Miceli Università di Palermo, INAF - Osservatorio Astronomico di Palermo Collaborators: F. Bocchino, D. Iakubovskyi, S. Orlando, I. Telezhinsky, M. Kirsch, O. Petruk, G. Dubner, G. Castelletti Miceli et al. X-ray emission of SN 1006, Boston 2009
Introduction We study the rim of SN 1006 to study how particle acceleration affects the structure of the remnant. We focus both on thermal and non-thermal X-ray emission. Aims: Physical and chemical properties of the X-ray emitting plasma to find Tracer of shock-modification (distance BW-CD, post-shock T, etc.) • Data: • XMM-Newton archive observations (7 obs. in 2000-2005, ~7-30 ks each) • VLA and single dish radio data to constrain the non-th. radio flux (VLA AB, BC and CD in 1991-1992; Single dish Parkes in 2002 added; Synth. beam 7”.7x4”.8) Miceli et al. X-ray emission of SN 1006, Boston 2009
Spectral analysis We select 30 regions at the rim and adopt a unique model to explain different spectral properties in terms of azimuthal variations of best-fit parameters One thermal component in NEI + one non-thermal component (SRCUT) Te, t, EM, abundances – NEI thermal component F1 GHz, nroll, a– non-thermal component (srcut, Reynolds 98) Miceli et al. X-ray emission of SN 1006, Boston 2009
What we do not see: the ISM Thermal component with oversolar abundances: we can detect the ejecta (see below), but where’s the shocked ISM? Is it too cold to emit X-rays? Or too tenous for the available statistics? If we add another thermal component to model the ISM emission the quality of the fit does not improve (even in “thermal” regions) and we have too many free parameters and useless results We cannot constrain signatures of shock modification in the thermodynamics of the post-shock ISM (low T, large n, etc.). Need for deeper observations (XMM LP, PI A. Decourchelle), see Gilles Mauren’s talk In literature the presence of ISM is controversial: Acero et al. (2007) find that at NW and SE (thermal regions) ISM is statistically not needed (if they include the SRCUT) and estimate kTISM~1.5 keV, while Yamaguchi et al. 2008 estimate that at SE kTISM~0.5 keV Miceli et al. X-ray emission of SN 1006, Boston 2009
What we see: 1) synchrotron emission S W N E S W N E • Profile of nbreak consistent with Rothenflug et al. (2003) • a~0.5 and values of nbreak in agreement with Allen et al. (2008) Miceli et al. X-ray emission of SN 1006, Boston 2009
What we see: 2) ejecta We determine the abundances in two large thermal regions: NW and SE Anisotropies in T and abundances Miceli et al. X-ray emission of SN 1006, Boston 2009
What we see: 2) ejecta SW limb NE limb kT (keV) tPS(cm-3 s) EM (cm-5 pc) Ejecta EM drops down in non-thermal limbs! Miceli et al. X-ray emission of SN 1006, Boston 2009
Pure thermal image • For each pixel we extrapolate the contribution of the non-thermal emission in the (0.5-0.8 keV band) from the image in the 2-4.5 keV band • The procedure relies only on the spectral results of the SRCUT component (robust and in agreement with those reported in literature Miceli et al. X-ray emission of SN 1006, Boston 2009
Pure thermal image SW limb NE limb Low values of EM in non-thermal limbs are naturally explained as volume effects Miceli et al. X-ray emission of SN 1006, Boston 2009
Blast wave – Contact Discontinuity We determine the position of the blast wave shock from the 2-4.5 keV image and from the Ha map (Winkler et al. 2003). Same approach as Cassam-Chenai et al. (2008), but we use our thermal image in the 0.5-0.8 keV band to determine the position of thecontact discontinuity Miceli et al. X-ray emission of SN 1006, Boston 2009
Comparison with MHD models shock front 3-D MHD model of non-modified SNR shock (see S. Orlando’s talk) 3-D simulations can model the Richtmyer-Meshkov instabilities and the “fingers” of ejecta Model parameters: ejecta Miceli et al. X-ray emission of SN 1006, Boston 2009
Comparison with MHD models The shock is modified everywhere. No lower ratios in non-thermal limbs: we do not observe regions with larger efficiency of the acceleration processes edge-on. Aspect angle < 90º g=5/3 g=4/3 g=1.1 Miceli et al. X-ray emission of SN 1006, Boston 2009
Conclusions • No X-ray emission from the ISM • Revised values of a and nbreak • Inhomogeneities in the ejecta (temperature and abundances) • Pure thermal image of the ejecta • Azimuthal profile of BW/CD • Shock modified everywhere • Aspect angle < 90º (see F. Bocchino’s talk) Miceli et al. 2009, A&A, in press Miceli et al. X-ray emission of SN 1006, Boston 2009