X-ray signature of shock modification in SN 1006

Supernova Remnants and Pulsar Wind Nebulae in the Chandra Era

July 8-10 2009, Boston, USA

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 analysisWe 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, , EM, abundances – NEI thermal component

F1 GHz, roll, – 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

Profile of break consistent with Rothenflug et al. (2003) ~0.5 and values of break in agreement with Allen et al. (2008)

S W N E

S W N E

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

Ejecta EM drops down in non-thermal limbs!

SW limb NE limb

kT (

keV

)

P

S (

cm-3 s

)

E

M (

cm-5 p

c)

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

Miceli et al. X-ray emission of SN 1006, Boston 2009

We determine the position of the blast wave shock from the 2-4.5 keV image and from the H 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 the contact discontinuity

Blast wave – Contact Discontinuity

Comparison with MHD models

3-D MHD model of non-modified SNR shock (see S. Orlando’s talk)

Model parameters:

ejecta

shock front

3-D simulations can model the Richtmyer-Meshkov instabilities and the “fingers” of ejecta

Miceli et al. X-ray emission of SN 1006, Boston 2009

Comparison with MHD models

5/3

4/3

1.1

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

Miceli et al. X-ray emission of SN 1006, Boston 2009

Conclusions

No X-ray emission from the ISM

Revised values of and break

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 pressMiceli et al. X-ray emission of SN 1006, Boston 2009