Sladjana

We present Fabry-Perot interferometric observations of the narrow Halpha component in the shock front of the historical supernova remnant Tycho (SN 1572). Using GHaFaS (Galaxy Halpha Fabry-Perot Spectrometer) on the William Herschel Telescope, we observed a great portion of the shock front in the northeastern region of the remnant. The high spatial (~0.2″/pixel) and spectral resolution (FWHM of 19 km/s) together with the large field-of-view (3.4’x3.4′) of the instrument allow us to measure the narrow Halpha-line width across individual parts of the shocks simultaneously and thereby study the indicators of several shock precursors in a large variety of shock front conditions. Covering one-fourth of the remnant’s shell, we find a strong evidence for the broadening of the narrow Halpha line beyond its intrinsic width of ~ 20 km/s and a presence of an intermediate component with width of order ~150 km/s. Suprathermal narrow-line widths point toward an additional heating mechanism in the form of a cosmic-ray precursor, while the intermediate component, previously only qualitatively reported as a small non-Gaussian contribution to the narrow component, reveals a broad-neutral precursor.