RADIO AND X-RAY OBSERVATIONS OF SN 2006jd: ANOTHER STRONGLY INTERACTING TYPE IIn SUPERNOVA

Abstract

We report four years of radio and X-ray monitoring of the Type IIn supernova\nSN 2006jd at radio wavelengths with the Very Large Array, Giant Metrewave Radio\nTelescope and Expanded Very Large Array; at X-ray wavelengths with {\\em\nChandra}, {\\em XMM-Newton} and {\\em Swift}-XRT. We assume that the radio and\nX-ray emitting particles are produced by shock interaction with a dense\ncircumstellar medium. The radio emission shows an initial rise that can be\nattributed to free-free absorption by cool gas mixed into the nonthermal\nemitting region; external free-free absorption is disfavored because of the\nshape of the rising light curves and the low gas column density inferred along\nthe line of sight to the emission region. The X-ray luminosity implies a\npreshock circumstellar density $\\sim 10^6$ cm$^{-3}$ at a radius $r\\sim 2\\times\n10^{16}$ cm, but the column density inferred from the photoabsorption of X-rays\nalong the line of sight suggests a significantly lower density. The implication\nmay be an asymmetry in the interaction. The X-ray spectrum shows Fe line\nemission at 6.9 keV that is stronger than is expected for the conditions in the\nX-ray emitting gas. We suggest that cool gas mixed into the hot gas plays a\nrole in the line emission. Our radio and X-ray data both suggest the density\nprofile is flatter than $r^{-2}$ because of the slow evolution of the\nunabsorbed emission.\n