The observation and future prospect of temperature gradient in the shock of SN1006 T. Kasuga, H. Odaka, A. Bamba, Y. Kato (The University of Tokyo), S. Katsuda (Saitama University), H. Suzuki (Konan University),K. Nakazawa (Nagoya University) [1]Vink, J., Laming, J. M., Gu, M. F., Rasmussen, A., and Kaastra, J. S., “The Slow Temperature Equilibration behind the Shock Front of SN 1006”,The Astrophysical Journal, vol. 587, no. 1, pp. L31‒L34, 2003. doi:10.1086/375125. [2] Yamaguchi, H., Eriksen, K. A., Badenes, C., et al. 2014, ApJ, 780, 136. doi:10.1088/0004- 637X/780/2/136 [3] http://x-ifu.irap.omp.eu/x-ifu/key-capabilities Introduction We find that the electron temperature increases toward downstream in the northwestern shock-heated plasma of SN 1006. Athena observation expects to show us the spatial variation of ion temperature. This will lead to our understanding of the shock heating and relaxation mechanism in SNRs. Our recent study with Chandra : Electron temperature of SN1006 NW shock Data set • ObsID 1959 (April, 2001, 88.98 ks) • ObsID 13737 (April, 2012, 87.09 ks) Region size : 140” ×15” Fig.4 Comparison of observed temperatures to a Coulomb scattering model ATHENA study : Ion temperature Our objective : Understanding the mechanism of collisionless heating and thermal relaxation after heating Fig.3 The spectra and besf-fit models. These spectra imply that the inner region, layer 1, has higher temperature than the outer region, layer 4 10−3 0.01 0.1 1 normalized counts s−1 keV−1 0.6 0.8 1 1.2 1.4 1.6 1.8 2 −2 0 2 4 (data−model)/error Energy (keV) 1959 - layer1 - layer4 13737 - layer1 - layer4 Result • Electron temperature increases toward inner region • Electron temperature increase is estimated to be slower than Coulomb scattering Fig.2 Chandra X-ray image of the northwestern region of SN 1006 with our analysis regions We want to observe the variation of ion temperature Why? → To understand shock heating and energy transfer system Near the shock front → Evaluate the efficiency of shock heating Inner region → Comparison to Coulomb scattering How? → From the width of each ion emission line ➡︎ Need observation with good energy and spatial resolution of Athena Spectral fitting Model : phabs × vnei kT, nt and some abundance are free Simulated Athena spectrum ・Using the best-fit model of center layer 1 ・Exposure time of 10 ks in total ・Smoothing spectrum with Gaussian to reproduce the line width derived from ion temperature from Rankin-Hugoniot relation Ne ( ) → Mg ( ) → Si ( ) → ・Replacing line emission by some gaussian, linking the width of each gaussian to show the same temperature Estimated temperatures : Ne → Mg → Si → ➡︎ Athena observation can distinguish mass-proportional ion temperature 307 keV 3.66 × 10−3 keV 370 keV 5.33 × 10−3 keV 428 keV 7.28 × 10−3 keV 335+15 −13 keV 404+258 −113 keV 566+438 −189 keV Reference Conclusion masahiro.ichihashi@phys.s.u-tokyo.ac.jp Masahiro Ichihashi (The University of Tokyo) Particle temperatures just after the collisionless heating are thought to be different between electron and ion[1] Ideal → (Rankine-Hugoniot relation) Several studies suggest breaking of this relation in the electron-to-proton ratio[2] The energy transfer of particles is caused after collisionless shock heating The simplest way → Coulomb scattering However, no observational evidence exist ➡︎Need to evaluate absolute values of each particle’s temperature by observation kTi = 3 16 miv2 s We sliced the shocked region to eaxmine the shock heeting mechanism. Fig.1 Schematic diagram of particle heating near shock wave shock front ISM vs post shock region Ion Electron Collisionless heating Equilibrium state kTi = 3 16 miv2 s (ideally) Energy transfer cold hot Fig.5 Simulation results of the Athena X-IFU spectra and Gaussian replacement of Ne line 0.01 0.1 1 10 counts s−1 keV−1 data and folded model 0.85 0.9 0.95 1 1.05 0 5 10 (data−model)/error Energy (keV) ichihashimasahiro 25−Oct−2022 16:58