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Understanding X and γ-ray emission of RX J

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1 Understanding X and γ-ray emission of RX J1713.7-3946
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd Understanding X and γ-ray emission of RX J Jean Ballet AIM, CEA Saclay, France Fabio Acero, Benjamin Condon, Marianne Lemoine-Goumard Fermi/LAT collaboration La Réunion, February 24, 2017

2 RX J with XMM-Newton CC SN, possible association with SN 393 Brightest TeV SNR Dominated by synchrotron emission in X-rays: shock- accelerated electrons Faint thermal X-rays  small ambient density < 0.1 cm-3 1° angular diameter, D = 1 kpc, 10 pc radius Many substructures, probably related to high-density clouds 1 degree Diffuse emission in North and South Band : keV Background subtracted Acero et al 2009, A&A 505, 157 Central compact object WR Star

3 Part I γ-ray (GeV to TeV) spectrum

4 Fermi/LAT spectrum 7.5 years Pass 8 data 200 MeV – 2 TeV
-10 -11 -12 -13 erg/cm2/s 1 10 100 GeV PRELIMINARY 7.5 years Pass 8 data 200 MeV – 2 TeV Break around 20 GeV favoured at 5 σ Benjamin Condon, Gamma 2016 (Heidelberg)

5 Leptonic interpretation
PRELIMINARY Benjamin Condon, Gamma 2016 (Heidelberg) B = 15 μG; nH = 0.1 cm-3; We = erg; Wp = erg (p = 2.1) BPL electron spectrum with p1 = 1.8; Eb = 0.5 TeV; p2 = 2.5 Good fit but where does the break come from ?

6 Cooling break ? The current B field Bf is limited by the small X/γ ratio to about 15 μG but it could have been much larger in the past CC SNR in progenitor’s wind Turbulent amplified magnetic field Injection Synchrotron cooling Ef break energy at current time tf for electrons accelerated at t0 The combination of decreasing injection and cooling generates a curved spectrum

7 X-ray vs γ-ray (TeV) morphology
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd Part II X-ray vs γ-ray (TeV) morphology

8 X/gamma indices at HESS scale
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/gamma indices at HESS scale Small scale 1.9< x<2.6 Large scale + PSF : 2.2< x<2.4 2,32 Esync= 27 TeV (B = 70 G) Esync= 50 TeV (B = 20 G) Eic = 16 TeV (on CMB) Region size ~ 5 pc 11 7 Pour 100uG : Eic=16 TeV Esyn=23 TeV Ep=12 TeV Bsup=200 uG Distribution meme ecart type Si emission purement IC 14 3 Acero et al 2009, A&A 505, 157 2 2,09 12 1

9 X/Gamma-ray flux correlation
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray flux correlation Larger contrast between regions in X-rays even at HESS resolution Si variation du a var de densite alors hadronique pbatique Car il augmente rapidement avec densite (cibles + part accel) tendance correlation autre sens Il faudrait s=7 pour hadronique puisse reprod Acero et al 2009, A&A 505, 157

10 Synchrotron, inverse Compton and π0 emission
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd Synchrotron, inverse Compton and π0 emission S loi de puissance de distrib de particules En ecrivant les freq de coupures en fonction de B et n Assume that the particle spectral shape does not change, only the cutoff energy does

11 X/Gamma-ray flux correlation
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray flux correlation Acero et al 2009, A&A 505, 157 Assumption : Flux variations are due to density variations Same pressure around SNR: Parameterization of B: (not obvious) Free parameters :  (< 1), p p = 2 (standard) αX = 1.32 (observed) S loi de puissance de distrib de particules En ecrivant les freq de coupures en fonction de B et n

12 X/Gamma-ray flux correlation
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray flux correlation Hadronic For 0 <  < 1 and p = 2 β = 1 β = 0 The hadronic model cannot provide the required slope Acero et al 2009, A&A 505, 157 Si variation du a var de densite alors hadronique pbatique Car il augmente rapidement avec densite (cibles + part accel) tendance correlation autre sens Il faudrait s=7 pour hadronique puisse reprod Tried other reasonable scalings. No way that the synchrotron emission can increase faster with density than the π0 emission

13 X/Gamma-ray flux correlation
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray flux correlation Leptonic β = 0 β = 1 For 0 <  < 1 and p = 2 The leptonic model is preferred. β = 0.3 works well Acero et al 2009, A&A 505, 157 Si variation du a var de densite alors hadronique pbatique Car il augmente rapidement avec densite (cibles + part accel) tendance correlation autre sens Il faudrait s=7 pour hadronique puisse reprod

14 X/Gamma-ray radial profiles
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray radial profiles Much deeper HESS observation γ-rays extend beyond X-rays (at HESS resolution) Interpreted as escaping particles No energy dependence (compared < 1 TeV to > 3 TeV) HESS collaboration et al 2017, arXiv

15 X/Gamma-ray morphology
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray morphology Similar to HESS collaboration work (probably not quite as clean) 1 – 4.5 keV HESS XMM-Newton convolved to same resolution

16 X/Gamma-ray morphology
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray morphology HESS XMM-Newton, Sqrt scaling Not good enough at low flux

17 X/Gamma-ray correlation
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray correlation Similar to previous result, with smaller pixels Absolute normalizations are arbitrary Current dynamic range in X-rays is ~ 200 γ α √X

18 X/Gamma-ray radial profiles
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray radial profiles Normalization on full image, same center as in HESS paper Smoothed X Region 3 profile Gaussian smoothing Expect truth to be between this and that √(smoothed X) Smoothed X1/2.4 0.6°

19 X/Gamma-ray radial profiles
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd X/Gamma-ray radial profiles Normalization on full image, same center as in HESS paper Region 3 Region 3, √X 0.6° Bad coverage, but faint emission far out

20 The large azimuthal brightness variations in the SNR
Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd Conclusion to part II The different X-ray and γ-ray morphologies could be explained as the consequence of: The large azimuthal brightness variations in the SNR The larger contrast in X-rays (γ α √X) Faint regions extending beyond bright ones (in projection) Most likely the larger radius in γ-rays has nothing to do with the physics of CR escape (which predicts energy dependence) Will know better after XMM-Newton LP (Acero, AO 17, 700 ks) Remains limited by angular resolution in γ-rays

21 Hfgdhgs Jhsdgfjsgf Jhsdfjsjffdfd sdhfhfgsd Conclusions The break around 20 GeV can be explained as a cooling break if the B field and injection were larger in the past; this is consistent with expansion in the wind of the progenitor The larger contrast in X-rays is easier to explain in a leptonic model, which is also consistent with the non detection of thermal X-ray emission at the blast wave The larger radius in γ-rays than X-rays is probably due to inhomogeneities and geometry, not physics


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