Explained Chandra’s unexpected detection of strong X-ray emission from a quasar jet as Compton scattering of CMB photons. Carried out a large survey of jets with Chandra and HST, discovering a dozen new extended X-ray and optical jets. First detection of infrared emission from extended jets with Spitzer. Showed through analysis of multiwavelength spectral energy distributions that local low-luminosity jets are powered by synchrotron process, while in luminous, high-redshift jets the X-rays come from the Compton/CMB process. Implies that jets are still expanding relativistically at tens or hundreds of kiloparsecs from the black hole that ultimately powers the jet, which in turn implies enormous kinetic energies.
Key papers:
The X-Ray Jet of PKS~0637-752: Inverse Compton Radiation from the Cosmic Microwave Background? F. Tavecchio, L. Maraschi, R. M. Sambruna, and C. M. Urry, 2000, ApJ Letters, 544, L23-L26
A Survey of Extended Radio Jets in AGN with Chandra and HST: First Results R. M. Sambruna, L. Maraschi, F. Tavecchio, C. M. Urry, C. Cheung, G. Chartas, R. Scarpa, and J. K. Reitz, 2002, ApJ, 571, 206-217
A Survey of Extended Radio Jets with Chandra and HST R. M. Sambruna, J. K. Gambill, L. Maraschi, F. Tavecchio, C. C. Cheung, C. M. Urry, G. Chartas, and R. Scarpa, 2004, ApJ, 608, 698-720
Spitzer IRAC Imaging of the Relativistic Jet from Superluminal Quasar PKS 0637-752 Y. Uchiyama. C. M. Urry, J. Van Duyne, C. C. Cheung, R. M. Sambruna, T. Takahashi, F. Tavecchio, and L. Maraschi, 2005, ApJL, 631, L113-116
The Naure of 3C 273 Jet as Revealed by the Spitzer Space Telescope Y. Uchiyama, C. M. Urry, C. C. Cheung, S. Jester, J. Van Duyne, R. M. Sambruna, T. Takahashi, F. Tavecchio, and L. Maraschi, 2006, ApJ, 648, 910-921