TYCHO SN 1572: A NAKED Ia SUPERNOVA REMNANT WITHOUT AN ASSOCIATED AMBIENT MOLECULAR CLOUD

Abstract

The historical supernova remnant (SNR) Tycho SN 1572 originates from the\nexplosion of a normal Type Ia supernova which is believed to have originated\nfrom a carbon-oxygen white dwarf in a binary system. We analyze the 21cm\ncontinuum, HI and 12CO-line data from the Canadian Galactic Plane Survey in the\ndirection of SN 1572 and surrounding region. We construct HI absorption spectra\nto SN 1572 and three nearby compact sources. We conclude that SN 1572 has no\nmolecular cloud interaction, which argues against previous claims that a\nmolecular cloud is interacting with the SNR. This new result does not support a\nrecent claim that dust, newly detected by AKARI, originates from such a\nSNR-cloud interaction. We suggest that the SNR has a kinematic distance of 2.5\n- 3.0 kpc based on a nonlinear rotational curve model. Very-high-energy\nGamma-ray emission from the remnant has been detected by the VERITAS telescope,\nso our result shows that its origin should not be an SNR-cloud interaction.\nBoth radio and X-ray observations support that SN 1572 is an isolated Type Ia\nSNR.\n