HST and MERLIN Observations of the Jet in 3C273

Abstract

We present red and blue images of the jet of the quasar 3C273 obtained with the WFPC2 on the Hubble Space Telescope as well as a new radio map made with the MERLIN array. The images are of significantly better quality than that of previous data. The two maps are aligned to an accuracy of 0.020$''$; this accuracy is achieved because both the quasar and the jet are contained in both the radio and optical images. The start of the optical jet is marked by an elongated knot which appears identical at radio and optical wavelengths. Other knots in the optical jet correspond to narrow oblique features within the radio outline. The total width of the smooth emission in the optical jet is~$0.7''$; the FWHM of the optical knots is~$0.3''$. The knots may trace the current location of a narrow, perhaps helical jet lying within the outlines of the older radio cocoon.