Conveners
Gamma-Ray: Gamma-Ray 1
- Thomas Bretz (RWTH Aachen University)
Gamma-Ray: Gamma-ray 2
- Jean-Philippe Lenain (LPNHE, CNRS/IN2P3)
Gamma-Ray: Gamma-ray 3
- David Thompson (NASA Goddard Space Flight Center)
Since 2008, the Large Area Telescope and the Gamma-ray Burst Monitor on the Fermi Gamma-ray Space Telescope have been monitoring the entire sky at energies from less than 10 keV to more than 1 TeV. Photon-level data and high-level data products are made publically available in near-real time, and efforts continue to improve the response time. This long-duration, all-sky monitoring has enabled...
Blazars exhibit strong variability, and abrupt changes in their flux are observed at high energies down to hour-, or even minute-time scales. Regular monitoring and prompt identication of these variations is key to organise quick follow-up observations. Thanks to its allsky monitoring capabilities, the Fermi-LAT is a very powerful instrument to survey the high energy sky and reveal such...
The First G-APD Cherenkov Telescope (FACT) has been monitoring blazars at TeV energies for more than six years. Because of the automatic operations and the usage of robust solid state photosensors (SiPM, aka G-APDs), it has been possible to collect a large and unbiased data sample of more than 11,000 hours. One of the closest and brightest blazars in the gamma-ray/X-ray sky, Mrk 421, is...
The locations of emission of gamma-ray radiation in active galactic nuclei jet are highly debated and it range from light-hours to a few light-year in quasar jets. The situation is more complex in the case of flat spectrum radio quasars, where the gamma-rays photons above 10 GeV may interact with the UV radiation from broad line region and get absorbed. I will be talking about the recent...
PKS 1510-089 is one of only a handful of flat spectrum radio quasars detected in very high energy (VHE, E > 100 GeV) gamma rays. Since the first detection in 2009, the source has been monitored VHE. Here, we present one special event that is a direct result of the monitoring effort. In May 2016, a major VHE gamma-ray flare was observed from PKS 1510-089 by the H.E.S.S. and MAGIC telescopes....
Blazars are known to show variability on time scales from minutes to
years. This complicates the measurement of their ground state. For
this, long-term monitoring is important to increase the chance to study
the source in an all-time low state.
The First G-APD Cherenkov Telescope (FACT) is monitoring bright TeV
blazars since more than six years and has collected between 1500 and
3000 hours of...
The High-Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view instrument under operations since March 2015 and located in the state of Puebla, México. HAWC observes two thirds of the sky daily at energies between 0.1 and 100 TeV with a duty cycle greater than 95%. This capability allows us to monitor unbiasedly known sources as the Mrk 421 blazar, to search blindly for transient...
The COMPTEL experiment aboard the Compton Gamma-Ray Observatory (CGRO) explored
the MeV sky (0.75 - 30 MeV) for more than 9 years between April 1991 and June 2000,
providing many discoveries. Now, more than 18 years after the deorbit of CGRO, the
COMPTEL data are still the forefront of our knowledge on the non-thermal soft gamma-ray
sky (1 - 30 MeV), because no successor is yet operating.
The...
Blazars are extremely variable objects emitting radiation across the electromagnetic spectrum and showing variability on time scales from minutes to years. Simultaneous multi-wavelength observations are crucial for understanding the emission mechanisms. From radio via optical, X-ray to gamma rays, a variety of instruments, as Fermi and OVRO, are already monitoring blazars. At TeV energies,...
