Prospects for detecting light echoes of galactic supernovae by wide-angle polarimetry

Abstract

We propose to use a global (wide-angle, of the order of several degrees) distribution of linearly polarized emission over the sky to detect light echoes of historical supernovae exploded in our Galaxy. The echo emission must be polarized tangential to the direction of the supernova explosion site, and its degree of polarization must exhibit a characteristic dependence on angular distance. The near infrared is an optimum spectral range for detection. A spotted structure in the shape of a ring ∼5° in diameter and ∼3° in width with a total brightness of ∼12–13^m in polarized light with a tangential orientation of the electric vector must be currently seen in the direction where Tycho Brahe observed a supernova explosion in 1572. A comparison of the expected intensity of the echo with the intensities of the zodiacal light and the atmosphere shows that it can be detected in principle during long-term observations from space and, under favorable conditions, even from the ground.