SPATIAL DISTRIBUTION OF X-RAY EMITTING EJECTA IN TYCHO’S SNR: INDICATIONS OF SHOCKED TITANIUM

Abstract

Young supernova remnants show a characteristic ejecta-dominated X-ray emission that allows us to probe the products of the explosive nucleosynthesis processes and to ascertain important information about the physics of the supernova explosions. Hard X-ray observations have recently revealed the radioactive decay lines of 44Ti at ~67.9 keV and ~78.4 keV in the Tycho's SNR. We here analyze the set of XMM-Newton archive observations of the Tycho's SNR. We produce equivalent width maps of the Fe K and Ca XIX emission lines and find indications for a stratification of the abundances of these elements and significant anisotropies. We then perform a spatially resolved spectral analysis by identifying five different regions characterized by high/low values of the Fe K equivalent width. We find that the spatial distribution of the Fe K emission is correlated with that of the Cr XXII. We also detect the Ti K-line complex in the spectra extracted from the two regions with the highest values of the Fe and Cr equivalent widths. The Ti line emissions remains undetected in regions where the Fe and Cr equivalent widths are low. Our results indicate that the post-shock Ti is spatially co-located with other iron-peak nuclei in Tycho's SNR, in agreement with the predictions of multi-D models of Type Ia supernovae.