Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Klein-Nishina”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

21 records · Page 2

A Hadronic Synchrotron Mirror Model for the "Orphan" Tev Flare in 1ES 1959+650

Very high energy gamma-ray flares of TeV blazars are generally accompanied by simultaneous flaring activity in X-rays. The recent observations by the Whipple collaboration of an "orphan" TeV flare of 1 ES 1959+650 (without a simultaneous X-ray flare) are very difficult to reconcile with the standard leptonic synchrotron self-Compton model, which is routinely very successfully employed to explain the spectral energy distribution and spectral variability of TeV blazars. In this paper an alternative scenario is suggested in which the orphan TeV flare may originate from relativistic protons, interacting with an external photon field supplied by electron synchrotron radiation reflected off a dilute reflector. While the external photons will be virtually "invisible" to the comoving ultrarelativistic electrons in the jet because of Klein-Nishina effects, their Doppler-boosted energy is high enough to excite a Delta-resonance from relativistic protons with Lorentz factors of gamma(sub p) approx. 10(exp 3)-10(exp 4). This model is capable of explaining the orphan TeV flare of 1ES 1959+650 with plausible parameters, thus constraining the number and characteristic energy of relativistic protons in the jet of this blazar.

Bottcher, Markus↗

A Diagnostic Test for Determining the Location of the GeV Emission in Powerful Blazars

An issue currently under debate in the literature is how far from the black hole is the Fermi-observed GeV emission of powerful blazars emitted. Here we present a clear diagnostic tool for testing whether the Ge V emission site is located within the sub-pc broad emission line (BLR) region or further out in the few pc scale molecular torus (MT) environment. Within the BLR the scatteri~ takes place at the onset of the Klein-Nishina regime, causing the electron cooling time to become almost energy independent and as a result, the variation of high-energy emission is expected to be achromatic. Contrarily, if the emission site is located outside the BLR, the expected GeY variability is energy-dependent and with amplitude increasing with energy. We demonstrate this using time-dependent numerical simulations of blazar variability.

Dotson, Amanda↗

A Method for Localizing Energy Dissipation in Blazars Using Fermi Variability

The distance of the Fermi-detected blazar gamma-ray emission site from the supermassive black hole is a matter of active debate. Here we present a method for testing if the GeV emission of powerful blazars is produced within the sub-pc scale broad line region (BLR) or farther out in the pc-scale molecular torus (MT) environment. If the GeV emission takes place within the BLR, the inverse Compton (IC) scattering of the BLR ultraviolet (UV) seed photons that produces the gamma-rays takes place at the onset of the Klein-Nishina regime. This causes the electron cooling time to become practically energy independent and the variation of the gamma-ray emission to be almost achromatic. If on the other hand the -ray emission is produced farther out in the pc-scale MT, the IC scattering of the infrared (IR) MT seed photons that produces the gamma-rays takes place in the Thomson regime, resulting to energy-dependent electron cooling times, manifested as faster cooling times for higher Fermi energies. We demonstrate these characteristics and discuss the applicability and limitations of our method.

Dotson, Amanda↗