HIGH ENERGY EMISSION FROM HIGH ENERGY EMISSION FROM SNR RX - PowerPoint PPT Presentation

HIGH ENERGY EMISSION FROM HIGH ENERGY EMISSION FROM SNR RX J1713.7-3946 SNR RX J1713.7-3946 Giovanni Morlino Giovanni Morlino INAF/Osservatorio Astrofisico di Arcetri In collaboration with: Elena Amato, Pasquale Blasi & Damiano Caprioli TeV Particle Astrophysics Paris, July 19 th - 23 th , 2010 G. Morlino, Paris - 21 July 2010

TeV Emission: TeV Emission: Hadronic or Leptonic Origin? Hadronic or Leptonic Origin? Aim Investigating whether the SNR RX J1713.7- 3946 can be an efficient Cosmic Rays accelerator, studying the origin of TeV  -ray emission Method We use the nonlinear diffusive shock acceleration theory coupled with resonant magnetic field amplification to compute the nonthermal particle population and the associated photon emission G. Morlino, Paris - 21 July 2010

 -Rays SNRs in TeV  -Rays SNRs in TeV Vela Junior RX J1713.7 is one of 4 shell-like SNRs observed in TeV band All show correlation with non- RX J1713 thermal X-ray RCW 86 SN 1006 G. Morlino, Paris - 21 July 2010

Fermi-LAT view of RX J1713.7-3946 Fermi-LAT view of RX J1713.7-3946 RX J1713 has been detected by Fermi-LAT in GeV band: Faint source in a complicated region Extended source [Figures from Funk (2009)- Fermi Symposium II] G. Morlino, Paris - 21 July 2010

X-ray Observations and Magnetic Field X-ray Observations and Magnetic Field [Lazendic et al.(2004)] XMM + Chandra XMM + Chandra The magnetic field is a key parameter to understand the TeV emission Assuming that the thickness of X-ray rims is due to sever synchrotron losses, we can infer the magnetic field ~ 100 µ G 2 D 2 / u 2  R X =  1  4 D 2 / u 2 2  syn − 1 B 2 ~ 100  G G. Morlino, Paris - 21 July 2010

Basic Features of NLDSA model Basic Features of NLDSA model If acceleration is efficient CRs modify the shock structure in a complicated way. We need a nonlinear theory able to describe how all elements feedback on all others  we use an iterative method Shock structure determine the injection of particles in the acceleration process Thermal leackage Acceleration efficiency CRs produce magnetic turbulence determine the shock structure - resonant streaming instability Diffusion properties determine: Turbulence modifies - maximum energy diffusion properties - acceleration efficiency G. Morlino, Paris - 21 July 2010

Basic Features of NLDSA model Basic Features of NLDSA model We use the model described in Blasi (2002), Blasi et al. (2005), Amato & Blasi (2006) Results are presented in Morlino, Amato & Blasi (2009) Solution of stationary transport equation in a plane shock geometry Bohm-like diffusion coefficient in the local amplified magnetic field Particle injection according to the thermal leakage model INNOVATIVE ELEMENTS Resonant magnetic field amplification and compression Inclusion of dynamical reaction of amplified magnetic field onto the shock G. Morlino, Paris - 21 July 2010

Basic Features of NLDSA model Basic Features of NLDSA model Age ~ 1600 yr Distance ~ 1 kpc Pion decay Model Parameters T 0 Temperature (10 6 K) Inverse U sh shock speed Compton n 0 upstream density CMB+opt/IR B 0 upstr. magnetic field Synchrotron ~2-4 μ G X-rays ξ acceleration efficiency K ep injected e/p ratio Maximum energy of both electrons and protons are computed consistently using nonlinear theory in the amplified magnetic field G. Morlino, Paris - 21 July 2010

Leptonic Scenario: Inefficient Acceleration Leptonic Scenario: Inefficient Acceleration K ep n 0 [cm -3 ] T 0 [K] u 0 [km/s] B 0 [ µ G] ξ 0.01 10 6 1.5 4300 4.1 0. 013 B 2 [ µ G] R sub R tot B 1 /B 0 T 2 [keV] p p,max [GeV] t acc [yr] η ing ε 1.6 % 7.7 x 10 -7 3.96 4. 0 3 4. 0 2 3 2 3 9.3 x 10 4 1600 ICS contribution with IR+optical photons energy density ~ 24 times greater than the Galactic mean value G. Morlino, Paris - 21 July 2010

Hadronic Scenario: Efficient Acceleration Hadronic Scenario: Efficient Acceleration K ep n 0 [cm -3 ] T 0 [K] u 0 [km/s] B 0 [ µ G] ξ 0. 12 10 6 2.6 4300 3.8 8 x 10 -5 B 2 [ µ G] R sub R tot B 1 /B 0 T 2 [keV] p p,max [GeV] t acc [yr] η ing ε 2 6 % 6. 5 x 10 -5 3. 9 5 5. 3 5 25. 5 100 19. 5 1.25 x 10 5 780 Thermal emission for T e = T p Thermal emission for T e = 0.01 T p G. Morlino, Paris - 21 July 2010

Thermal X-ray lines: Thermal X-ray lines: is the Hadronic Scenario ruled out? is the Hadronic Scenario ruled out? − 3 n 0 = 0. 2 cm Ellison et al. (2010) showed that If ISM density ~ 0.1 cm -3 → Coulomb collisions can heat electrons enough to produce observable X-ray lines above the Suzaku observed flux − 3 n 0 = 0. 05 cm G. Morlino, Paris - 21 July 2010

Thermal X-ray lines: Thermal X-ray lines: is the Hadronic Scenario ruled out? is the Hadronic Scenario ruled out? − 3 n 0 = 0. 2 cm Ellison et al. (2010) showed that If ISM density ~ 0.1 cm -3 → Coulomb collisions can heat electrons enough to produce observable X-ray lines above the Suzaku observed flux Possible caveats: Chemical composition of circumstellar medium different from the assumed solar one Non uniform circumstellar medium [see Zirakashvili & Aharonian 2009] − 3 n 0 = 0. 05 cm G. Morlino, Paris - 21 July 2010

Conclusions Conclusions The dispute between Hadronic vs Leptonic scenario is still not solved Non-thermal Thermal X-ray GeV TeV X-ray filaments X-ray (Fermi-LAT) HADRONIC GOOD BAD NOT SO GOOD GOOD (efficient GOOD acceleration) LEPTONIC GOOD GOOD GOOD BAD BAD (inefficient acceleration) G. Morlino, Paris - 21 July 2010

X-rays variability X-rays variability Uchiyama et al.(2008) observed whit CHANDRA rapid variations of single X-ray spots of order ~1 year Assuming that this is due to synchrotron losses they infer a magnetic field ~mG observing G. Morlino, Paris - 21 July 2010

Predictions from other Authors Predictions from other Authors G. Morlino, Paris - 21 July 2010