Neutral Hydrogen Towards Tycho’s Supernova Remnant

Abstract

We have observed the radio remnant of Tycho’s Supernova (AD 1572), 3C10, with the Cambridge Half-Mile-Telescope (HMT). Two complete syntheses, overlapping in velocity coverage, were made in September 1979. Details of the telescope, receivers and the survey are in Table 1. In order to derive accurate HI absorption measurements towards the source, it is important to include carefully the contribution from large scale emission. Data containing this large-scale structure, physically unobtainable with the HMT, were derived from the work of Weaver & Williams (1973) and Williams (1973), and added to the synthesis maps. Continuum emission was subtracted from these ‘composite’ maps to give the final channel maps (Plate 1). In Plate 2 we show a ‘pie slice’ representation of an RA-velocity plot through the centre of the field.