Neutral hydrogen towards 3C 10, the remnant of Tycho's supernova

Abstract

Aperture synthesis observations of neutral hydrogen towards the remnant of Tycho's supernova (AD 1572), 3C 10, have been made with the Cambridge Half-Mile Telescope. Details of the absorption features indicate that the distance of 3C 10 is in the range of 1.7–3.7 kpc. The neutral hydrogen in a cloud in the local arm has a spin temperature ∼80 K and an optical depth of order unity. Numerous arc and filamentary structures are seen in emission; some have been analyzed in terms of expanding shells. These are found to have H I masses between 500 M⊙ and |$2.8\times10^5M_\odot$|⁠, and H I kinetic energies between 3.5×1040 J and 6×1043 J. Stellar winds are proposed as energy sources for two of the arcs because three open clusters are near the center of curvature of one, and a bright star near the center of the other. An open cluster, three 9th mag stars and two CO clouds are seen to coincide with various minima in the H I emission. Two other CO clouds coincide with bright H I emission features, as does the small H II region S175.