Markos Georganopoulos University of Maryland Baltimore County

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Markos GeorganopoulosUniversity of Maryland
Baltimore CountyNASA Goddard

• Is the GeV emission of blazars really produced
  inside the broad line region?

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External Compton scattering off the broad line
10 eV photons

• Sikora, Begelman, Rees 94
• gtSpherical broad line region
• with R1017-18 cm
• Uo ? UBLR G2
• ?o??BLR G ? 2 10 -4 in mc2 units

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Observed Compton dominance up to 100 gtExternal
Compton losses dominate
Kubo et al 98
photons of few GeV ?
electrons of at least the same energy (?104)
For seed photons ?o10-4 ?o?1 GeV emission
comes from scatterings in the gray area between
the Thomson and Klein-Nishina regimes
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The devil is in the details
At GeV electron energies the cooling time is
energy independent! Effect on n(?) ?
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The devil is in the details
At GeV electron energies the cooling time is
energy independent! Effect on n(?) ?
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The electron distribution
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How EC dominated blazars should look

• Unavoidable but unobserved marks
• The hump in the synchrotron component
• 2. The flat/rising SED of the GeV component
  (rarely seen, typical GeV spectrum is steep)
• 3. Achromatic variability for the synchrotron
  hump and the GeV regime.

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How EC dominated blazars should look

• Unavoidable but unobserved marks
• The hump in the synchrotron component
• 2. The flat/rising SED of the GeV component
  (rarely seen, typical GeV spectrum is steep)
• 3. Achromatic variability for the synchrotron
  hump and the GeV regime.

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Download the code at

• www.jca.umbc.edu/markos/cs

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