Related papers: Multi-wavelength observations of H.E.S.S. AGN

Multi-messenger astrophysics is a fast-growing, interdisciplinary field that combines data, which vary in volume and speed of data processing, from many different instruments that probe the Universe using different cosmic messengers:…

Radio observations of very high energy (VHE) gamma-ray sources are fundamental to identify and reveal their nature, as well as to understand the physics behind these energetic sources. I will comment on some characteristics of extragalactic…

One of the mysteries of very-high-energy (VHE) astrophysics is the observation of flat spectrum radio quasars (FSRQs) above about 30 GeV, because at those energies their broad line region should prevent photons produced by the central…

Observations at multiple wavelengths are reviewed to search for evidence for fueling mechanisms in galaxies, both for nuclear starbursts and AGN activity. Although it is undisputed that dynamical perturbations such as bars or tidal…

The last decade has seen tremendous developments in gamma-ray astronomy with the extragalactic sky becoming highly populated by Active Galactic Nuclei (AGNs). This brief review highlights some of the progress in AGN research achieved over…

The broadband emission observed from radio galaxies, BL Lac objects and quasars is thought to be produced by energetic electrons confined in plasma blobs which are ejected from supermassive black holes at relativistic speeds. The lower…

Whilst astronomy as a science is historically founded on observations at optical wavelengths, studying the Universe in other bands has yielded remarkable discoveries, from pulsars in the radio, signatures of the Big Bang at submm…

During the coming decade, high energy physics experiments at the Fermilab Tevatron and around the globe will use very sophisticated equipment to record unprecedented amounts of data in the hope of making major discoveries that may unravel…

The BL Lac type object Mrk 501 was observed at very high energies (E > 100 GeV) in 2014 with the upgraded H.E.S.S. (High Energy Stereoscopic System) phase 2 array. The data collected with the central 28m telescope allow for a broader energy…

This paper presents a review of the history, motivation and current status of high energy neutrino telescopes. Many years after these detectors were first conceived, the operation of kilometer-cubed scale detectors is finally on the horizon…

The center of the Galaxy is a prominent source in X-rays and gamma-rays. The study of its high-energy (HE) emission is crucial in understanding the physical phenomena taking place in this dense and extreme environment, where the closest…

The black-hole/accretion-disk paradigm for active galactic nuclei (AGNs) is now reasonably secure, but there are still important unresolved issues, some of which will require the capabilities of an 8 to 10-m class UV/optical space-based…

Multimessenger observations may hold the key to learn about the most energetic sources in the universe. The recent construction of large scale observatories opened new possibilities in testing non thermal cosmic processes with alternative…

Understanding the formation and evolution of the stellar-mass binary black holes discovered by LIGO and Virgo is a challenge that spans many areas of astrophysics, from stellar evolution, dynamics and accretion disks, to possible exotic…

We present an optical to X-ray spectral analysis of four 'hypervariable' AGN (HVAs) discovered by comparing Pan-STARRS data to that from SDSS over a 10 year baseline (Lawrence et al 2016). There is some evidence that these objects are X-ray…

High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The seven or more pulsars seen by instruments on the Compton Gamma Ray Observatory (CGRO) show that: the…

I review here some of the main observational features in microquasars and AGNs as sources of high-energy gamma-rays as well as some of the current models that try to explain the emission in the gamma-ray domain.

In this white paper we describe the prospects for ASTRO-H for the study of outflows from active galactic nuclei. The most important breakthroughs in this field are expected to arise from the high spectral resolution and sensitivity in the…

Multi-messenger astronomy provides for the observation of the same astronomical event with different kind of telescopes at the same time: optical observations, X-rays, gamma-ray bursts, neutrinos and, most recently, gravitational waves are…

Black hole accretion in active galactic nuclei (AGN) is coupled to the evolution of their host galaxies. Outflowing winds in AGN can play an important role in this evolution through the resulting feedback mechanism. Multi-wavelength…