A Deep ROSAT HRI X-ray Image of the Remnant of SN 1572 (Tycho's SN)

The color image above depicts the X-ray emission from the remnant of Tycho's supernova as observed in a 104,000 second long observation by the ROSAT High Resolution Imager (HRI). Most of the bright regions correspond to clumps of metal enriched material ejected from the star that exploded as a supernova over 400 years ago. This image is about five times deeper than any previous high resolution X-ray image and it reveals some new features. Most notable is the weak rim of emission seen clearly around the entire remnant, which is believed to be the blast wave propagating through the surrounding circumstellar (or interstellar) medium.

This pointing was actually the second ROSAT observation of Tycho's SNR carried out by the HRI. The first one was done some 4.5 years earlier and so the time baseline between the two pointings is roughly 1% of the age of the SNR which exploded as a supernova in AD1572. The two separate ROSAT observations were used to measure the expansion rate of the X-ray remnant. For more details about this work please see the article "The Expansion of the X-Ray Remnant of Tycho's Supernova (SN 1572)" by Hughes which will appear in an upcoming issue of The Astrophysical Journal Letters.

Revised October 12, 2000