Evidence of Gradients of Density and Magnetic Field in the Remnant of Tycho’s Supernova

Abstract

By using surface brightness maps of Tycho's supernova remnant (SNR) in radio and X-rays, along with the properties of thermal and synchrotron emission, we have derived the postshock density and magnetic field (MF) strength distributions over the projection of this remnant. Our analysis reveals a density gradient oriented toward the northwest, while the MF strength gradient aligns with the Galactic plane, pointing eastward. Additionally, utilizing this MF map, we have derived the spatial distributions of the cutoff frequency and maximum energy of electrons in Tycho's SNR. We further comment on the implications of these findings for interpreting the gamma-ray emission from Tycho's SNR.