The Origin of the Fe-rich Knot in SN 1604

We propose a 200 ks XMMNewton observation of the Ferich knot in the Type Iasupernova remnant of Kepler to confirm that the explosion originated from anearChandrasekharmass white dwarf (WD). Previous observations by Chandra haverevealed an Ferich ejecta knot within the SNR moving at nearly the freeexpansion speed. The current spectrum of the knot shows strong emission linesfrom Fepeak elements (Cr, Mn, Ni), pointing to an origin in the deepest layerof a nearChandrasekharmass WD. However, due to high background in the Chandradata, it is difficult to claim a significant detection of the Ni line, which iskey to determining the burning regime. Thanks to low background, highsensitivity in the Ni band, only the XMMNewton can resolve this important issue in SN Ia physics. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]