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Title: POLARIMETRY AND THE HIGH-ENERGY EMISSION MECHANISMS IN QUASAR JETS: THE CASE OF PKS 1136-135

Since the discovery of kiloparsec-scale X-ray emission from quasar jets, the physical processes responsible for their high-energy emission have been poorly defined. A number of mechanisms are under active debate, including synchrotron radiation, inverse-Comptonized cosmic microwave background (IC/CMB) emission, and other Comptonization processes. In a number of cases, the optical and X-ray emission of jet regions are inked by a single spectral component, and in those, high-resolution multi-band imaging and polarimetry can be combined to yield a powerful diagnostic of jet emission processes. Here we report on deep imaging photometry of the jet of PKS 1136-135 obtained with the Hubble Space Telescope. We find that several knots are highly polarized in the optical, with fractional polarization {Pi} > 30%. When combined with the broadband spectral shape observed in these regions, this is very difficult to explain via IC/CMB models, unless the scattering particles are at the lowest-energy tip of the electron energy distribution, with Lorentz factor {gamma} {approx} 1, and the jet is also very highly beamed ({delta} {>=} 20) and viewed within a few degrees of the line of sight. We discuss both the IC/CMB and synchrotron interpretation of the X-ray emission in the light of this new evidence,more » presenting new models of the spectral energy distribution and also the matter content of this jet. The high polarizations do not completely rule out the possibility of IC/CMB optical-to-X-ray emission in this jet, but they do strongly disfavor the model. We discuss the implications of this finding, and also the prospects for future work.« less
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11] ;  [12]
  1. Department of Physics and Space Sciences, Florida Institute of Technology, 150 W. University Blvd., Melbourne, FL 32901 (United States)
  2. SLAC/KIPAC, Stanford University, 2575 Sand Hill Road, M/S 209, Menlo Park, CA 94025 (United States)
  3. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
  4. Yale University, Department of Astronomy, P.O. Box 208101, New Haven, CT 06520-8101 (United States)
  5. Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 (United States)
  6. Department of Physics, University of Bristol, Bristol, BS8 1TL (United Kingdom)
  7. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  8. Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)
  9. Institute of Space Astronautical Science, JAXA, 3-1-1 Yoshinodai, Chuo-Ku, Sagamihara, Kanagawa 252-5210 (Japan)
  10. Department of Astrophysical and Planetary Sciences, UCB 391, University of Colorado, Boulder, CO 80309-0391 (United States)
  11. Laboratory for Multiwavelength Astrophysics, School of Physics and Astronomy, Rochester Institute of Technology, 84 Lomb Memorial Dr., Rochester, NY 14623-5603 (United States)
  12. Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology, 54 Lomb Memorial Dr., Rochester, NY 14623-5604 (United States)
Publication Date:
OSTI Identifier:
22130956
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 773; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; EMISSION; ENERGY SPECTRA; PHOTOMETRY; POLARIMETRY; POLARIZATION; QUASARS; RELICT RADIATION; RESOLUTION; SCATTERING; SYNCHROTRON RADIATION; SYNCHROTRONS; TELESCOPES; X RADIATION