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Related papers: Tev Blazars: Status of Observations

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We propose a method of measurement of extragalactic magnetic fields in observations of TeV gamma-rays from distant blazars. Multi-TeV gamma-rays are emitted by these sources in narrow jet with opening angle of few degrees. These primary…

Astrophysics · Physics 2008-11-26 A. Neronov , D. V. Semikoz

We derive a relation for the steepening of blazar gamma-ray spectra between the multi-GeV Fermi energy range and the TeV energy range observed by atmospheric Cerenkov telescopes. The change in spectral index is produced by two effects: (1)…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-12 Floyd W. Stecker , Sean T. Scully

The magnetic fields that emerge from beneath the solar surface and permeate the solar atmosphere are the key drivers of space weather and, thus, understanding them is important to human society. Direct observations, used to measure magnetic…

Solar and Stellar Astrophysics · Physics 2024-05-29 Kenny C. Y. Ng , Andrew Hillier , Shin'ichiro Ando

This paper summarizes recents results in gamma-ray astronomy, most of which were derived with data from ground-based gamma-ray detectors. Many of the contributions presented at this conference involve multiwavelength studies which combine…

Astrophysics · Physics 2007-05-23 Martin Pohl

Introduced in 1998 to attempt a first unified view of the broad-band emission properties of blazars, the blazar sequence has been extensively used in the past 25 years to guide observations as well as physical interpretation of the overall…

High Energy Astrophysical Phenomena · Physics 2022-02-16 Elisa Prandini , Gabriele Ghisellini

Blazars are extremely variable objects emitting radiation across the electromagnetic spectrum and showing variability on time scales from minutes to years. For the understanding of the emission mechanisms, simultaneous multi-wavelength…

Instrumentation and Methods for Astrophysics · Physics 2017-08-09 Daniela Dorner , Thomas Bretz , Magdalena Gonzalez , Ruben Alfaro , Gagik Tovmassian

Recent observations have shown that pulsars are surrounded by extended regions which emit TeV-scale gamma rays through the inverse Compton scattering of very high energy electrons and positrons. Such TeV halos are responsible for a large…

High Energy Astrophysical Phenomena · Physics 2022-07-20 Fei Xu , Dan Hooper

The production site of gamma rays in blazars is closely related to their interaction with the photon fields surrounding the active galactic nucleus. In this paper, we discuss an indirect method that may help to unveil the presence of…

High Energy Astrophysical Phenomena · Physics 2022-02-21 L. Foffano , V. Vittorini , M. Tavani , E. Menegoni

A recent progress in the study of $\gamma$-ray jets is reviewed, with a focus on some theoretical interpretations of the VHE emission from M87, and possibly other misaligned blazars; the connection betwe en the GeV breaks exhibited by…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Amir Levinson

In recent years, ground-based TeV gamma-ray observatories have made spectacular discoveries including imaging spectroscopy observations of galactic sources of different classes, and the discovery of rapid gamma-ray flares from radio…

Blazars, a subset of powerful active galactic nuclei, feature relativistic jets that shine in a broadband electromagnetic radiation, e. g. from radio to TeV emission. Here I present the results of the studies that explore gamma-ray and…

High Energy Astrophysical Phenomena · Physics 2022-10-18 Gopal Bhatta

We discuss prospects for detecting a spectral break in gamma-ray spectra of blazars due to the extragalactic background light (EBL) density falling off between the near and mid-IR. A measurable spectral change in the TeV spectra at 1 TeV…

Astrophysics · Physics 2007-08-24 Asif Imran , Frank Krennrich

A new method to constrain the distance of blazars with unknown redshift using combined observations in the GeV and TeV regimes will be presented. The underlying assumption is that the Very High Energy (VHE) spectrum corrected for the…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-02 Elisa Prandini , Giacomo Bonnoli , Laura Maraschi , Mose' Mariotti , Fabrizio Tavecchio

Blazars are the most plentiful gamma-ray source at GeV energies, and despite detailed study, there is much that is not known about these sources. In this review I explore some recent results on blazars, including the controversy of the…

High Energy Astrophysical Phenomena · Physics 2013-03-22 Justin Finke

The launch of the Fermi gamma-ray space telescope and the imaging air Cerenkov telescopes H.E.S.S., MAGIC, and VERITAS have substantially transformed our knowledge of gamma-ray sources in the last decade. The extragalactic gamma-ray sky is…

High Energy Astrophysical Phenomena · Physics 2013-09-02 C. Pfrommer

The imprint of cosmic backgrounds in the gamma ray spectra of blazars has recently been detected by H.E.S.S. and Fermi-LAT, opening the way to studies of gamma-ray propagation on cosmological scales. This proceeding discusses the current…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Jonathan Biteau

The cosmic gamma-ray background radiation is one of the most fundamental observables in the gamma-ray band. Although the origin of the cosmic gamma-ray background radiation has been a mystery for a long time, the Fermi gamma-ray space…

High Energy Astrophysical Phenomena · Physics 2014-12-15 Yoshiyuki Inoue

An overview is given of high-energy gamma-ray and neutrino astronomy, emphasizing the links between the two fields. With several new large detectors just becoming operational, the TeV gamma-ray and neutrino sky will soon be surveyed with…

Astrophysics · Physics 2007-05-23 L. Bergstrom

TeV haloes are a recently discovered class of very high energy gamma-ray emitters. These sources consist of extended regions of multi-TeV emission, originally observed around the two well-known and nearby pulsars, Geminga and PSR B0656+14…

High Energy Astrophysical Phenomena · Physics 2024-09-04 Elena Amato , Sarah Recchia

We present a review of the current status of very high energy gamma-ray astronomy. The development of the atmospheric Cherenkov imaging technique for ground-based gamma-ray astronomy has led to a rapid growth in the number of observatories.…

Astrophysics · Physics 2009-10-31 Michael Catanese , Trevor C. Weekes