* Astronomy

Title: Radio and X-ray observations of SN 2006jd: Another strongly interacting Type IIn supernova
Authors: Poonam Chandra, Roger A. Chevalier, Nikolai Chugai, Claes Fransson, Christopher M. Irwin, Alicia M. Soderberg, Sayan Chakraborti, Stefan Immler

We report four years of radio and X-ray monitoring of the Type IIn supernova SN 2006jd at radio wavelengths with the Very Large Array, Giant Metrewave Radio Telescope and Expanded Very Large Array; at X-ray wavelengths with Chandra, XMM-Newton and Swift-XRT. We assume that the radio and X-ray emitting particles are produced by shock interaction with a dense circumstellar medium. The radio emission shows an initial rise that can be attributed to free-free absorption by cool gas mixed into the nonthermal emitting region; external free-free absorption is disfavoured because of the shape of the rising light curves and the low gas column density inferred along the line of sight to the emission region. The X-ray luminosity implies a preshock circumstellar density ~ 10^6 cm^{-3} at a radius r~ 2 x 10^{16} cm, but the column density inferred from the photoabsorption of X-rays along the line of sight suggests a significantly lower density. The implication may be an asymmetry in the interaction. The X-ray spectrum shows Fe line emission at 6.9 keV that is stronger than is expected for the conditions in the X-ray emitting gas. We suggest that cool gas mixed into the hot gas plays a role in the line emission. Our radio and X-ray data both suggest the density profile is flatter than r^{-2} because of the slow evolution of the unabsorbed emission.

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