1995A&A...299..193S

Westerbork Synthesis Radio Telescope HI observations combined with Effelsberg 100m antenna observations have been made of the galactic supernova remnant 3C 10 (Tycho) with an angular resolution ≃50" and a velocity resolution of 0.62km/s and with the VLA with resolutions of ∼13" and 1.3km/s, respectively. HI absorption against 3C 10 was detected in the velocity range -60≤v≤10km/s. The most negative velocity component is at -57km/s. HI absorption in the direction of extragalactic source 3C11.1 and two additional sources close to 3C 10 (distance ≲1deg) was obtained using the Very Large Array. Comparison of the spectra together with two other sources from Taylor & Roberts (1993AJ....106.1087T) (distance ≲2deg) leads to the conclusion that 3C 10 is at a distance of 4.5kpc. The implications of this distance are discussed. The HI absorption at -48km/s in the direction of 3C 10 shows a filament of size ∼4'. Self-absorption near 3C 10 is also detected at this velocity, and an upper limit of 25 K for the spin temperature can be derived. A comparison with a high resolution 100µ IRAS image is discussed. The HI absorption at low velocities (-20≤v≤+10km/s) shows primarily large scale structure. For this gas a spin temperature of 75K can be derived. All distances are based on R_☉=8.5kpc.