Related papers: Radio galaxies - the TeV challenge
Gamma-ray telescopes have reported some surprising observations of multi-TeV photons from distant active galactic nuclei (AGN), which show no significant attenuation due to pair production on either the extragalactic background light (EBL),…
We report on a detailed investigation of the gamma-ray emission from 18 broad line radio galaxies (BLRGs) based on two years of Fermi Large Area Telescope (LAT) data. We confirm the previously reported detections of 3C 120 and 3C 111 in the…
Some recent experiments detecting very high energy (VHE) gamma-rays above 10-20 TeV independently reported VHE bursts for some of bright gamma-ray bursts (GRBs). If these signals are truly from GRBs, these GRBs must emit a much larger…
This study investigates the environments and characteristics of Gamma-Ray Bursts (GRBs) exhibiting very high energy (VHE) emission. Recent detections of VHE emission, up to TeV energies, challenge synchrotron-only emission models and…
To understand Galactic objects that emits GeV-TeV emission, a spatial correlation study between the Fermi bright source catalog and TeV source population was carried out in Tam et al. (2010), finding that a significant number of very…
The detection of gamma-ray burst GRB~221009A has attracted significant attention due to its record brightness and the first-ever detection of multi-TeV $\gamma$-rays from a GRB. Located at redshift $z=0.151$, this event is relatively nearby…
BL Lac objects are known to have very energetic jets pointing towards the observer under small viewing angles. Many of these show high luminosity over the whole energy range up to TeV, mostly classified as high-energy peaked BL Lac objects.…
The synergy between the Fermi-LAT and ground-based Cherenkov telescope arrays gives us the opportunity for the first time to characterize the high-energy emission from blazars over 5 decades in energy, from 100 MeV to 10 TeV. In this study,…
Very-high-energy (VHE) photons around TeV energies from a gamma-ray burst (GRB) jet will play an essential role in the multi-messenger era, with a fair fraction of the events being observed off-axis to the jet. We show that different energy…
We present a systematic search for radio active galactic nuclei (AGNs) in dwarf galaxies using recent observations taken by the Very Large Array Sky Survey (VLASS). To select these objects, we first establish a criterion to identify…
Observations and detections of Active Galactic Nuclei (AGN) by Cherenkov telescopes are often triggered by information about high flux states in other wavelength bands. To overcome this bias, the VHE gamma-ray telescope MAGIC has conducted…
One of the principal results obtained by the EGRET experiment aboard the Compton Gamma-Ray Observatory (CGRO) was the detection of several Gamma-ray bursts (GRBs) above 100 MeV. The broad-band spectra obtained for these bursts gave no…
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…
We argue that gamma-ray bursts (GRBs) may be the origin of the cosmic gamma-ray background radiation observed in GeV range. It has theoretically been discussed that protons may carry a much larger amount of energy than electrons in GRBs,…
Radio Galaxies have by now emerged as a new $\gamma$-ray emitting source class on the extragalactic sky. Given their remarkable observed characteristics, such as unusual gamma-ray spectra or ultrafast VHE variability, they represent unique…
With the advent of imaging atmospheric Cherenkov telescopes in late 1980's, ground-based observation of TeV gamma-rays came into reality after struggling trials by pioneers for twenty years, and the number of gamma-ray sources detected at…
The first source catalog of Large High Altitude Air Shower Observatory reported the detection of a very-high-energy gamma ray source, 1LHAASO J1219+2915. In this paper a further detailed study of the spectral and temporal behavior of this…
Markarian 421 was the first extragalactic source to be detected with high statistical certainty at TeV energies. The Whipple Observatory gamma-ray telescope has been used to observe the Active Galactic Nucleus, Markarian 421 in 1996 and…
Galactic diffuse TeV gamma-ray emission is produced by the interaction of high-energy cosmic-ray particles with matter and radiation in our Galaxy. The measurement of Galactic diffuse TeV gamma-ray emission would provide strong constraints…
Radio galaxies have emerged as a new gamma-ray emitting source class on the extragalactic sky. With their jets misaligned, i.e. not directly pointing towards us, they offer a unique tool to probe some of the fundamental (and otherwise…