摘要:

The TeV energy spectrum of the Blazar type galaxy Mrk-501 extends beyond 16 TeV and constitutes the most energetic photons observed from an extragalactic object. A fraction of the emitted spectrum is possibly absorbed in interactions with low energy photons of the diffuse extragalactic infrared radiation, which in turn offers the unique possibility to measure the diffuse infrared radiation density by TeV spectroscopy. One of the recently published ideas to reduce the absorption of TeV photons is based upon the assumption that sources like Mrk-501 could produce Bose-Einstein condensates (BEC) of coherent photons. The condensates would have a higher survival probability during the transport in the diffuse radiation field and could mimic TeV air shower events. The powerful stereoscopic technique of the HEGRA air Cherenkov telescopes allows to test this hypothesis by reconstructing the penetration depths of TeV air shower events: Air showers initiated by BECs are expected to reach the maximum of the shower development in the atmosphere earlier than single photon events. By comparing the energy dependent penetration depths of TeV photons from Mrk-501 with those from the TeV standard candle Crab Nebula and simulated events, we can reject the hypothesis that TeV photons from Mrk-501 are pure BECs. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1370896

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

In previous papers (e.g. physics/0003080 and references therein), it was pointed out that Lorentz symmetry violation (LSV) at Planck scale can play a crucial role in astrophysical processes at very high energy. It can potentially inhibit radiation under external forces (e.g. synchrotron-like), GZK-like cutoffs, decays, photodisintegration of nuclei, momentum loss trough collisions (e.g. with a photon wind in reverse shocks), production of lower-energy secondaries&ellip; . An updated description of this phenomenon is presented, focusing on acceleration in relativistic shocks and having in mind a model where the effective parameter driving LSV would vary like the square of the momentum scale (Quadratically Deformed Relativistic Kinematics, QDRK). Implications for ultra-high energy (UHE) neutrino production are equally discussed. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1370897

出版商:AIP    

年代:1901

数据来源: AIP

摘要:

Lorentz symmetry violation (LSV) at Planck scale can be tested (see e.g. physics/0003080) through ultra-high energy cosmic rays (UHECR). In a deformed Lorentz symmetry (DLS) pattern where the effective LSV parameter varies like the square of the momentum scale (quadratically deformed relativistic kinematics, QDRK), a≈10−6 LSVat Planck scale would be enough to produce observable effects on the properties of cosmic rays at the≈1020&hthinsp;eVscale: absence of GZK cutoff, stability of unstable particles, lower interaction rates, kinematical failure of any parton model and of standard formulas for Lorentz contraction and time dilation&ellip; . Its phenomenological implications are compatible with existing data. If the effective LSV parameter is taken to vary linearly with the momentum scale (linearly deformed relativistic kinematics, LDRK), a LSV at Planck scale larger than≈10−7seems to lead to contradictions with data above ≈ TeV energies. Consequences are important for high-energy gamma-ray experiments, as well as for high-energy cosmic rays and gravitational waves. ©2001 American Institute of Physics.

ISSN:0094-243X    

DOI:10.1063/1.1370898

出版商:AIP    

年代:1901

数据来源: AIP