570 datasets found

It has been suggested that the prompt emission in gamma-ray bursts (GRBs) could be described by radiation from the photosphere in a hot fireball. Such models must be tested by...

In the most recent IBIS survey based on observations performed during the first 1000 orbits of INTEGRAL, are listed 363 high-energy emitters firmly associated with AGN, 107 of...

This work is a summary of the X-ray spectral studies of 29TeV (10^12^eV, tera-electron-volt) {gamma}-ray emitting blazars observed with Swift/XRT, especially focusing on sources...

We present first results from RoboPol, a novel-design optical polarimeter operating at the Skinakas Observatory in Crete. The data, taken during the 2013 May-June commissioning...

Follow-up observations of large numbers of gamma-ray burst (GRB) afterglows, facilitated by the Swift satellite, have produced a large sample of spectral energy distributions...

In this work we present the most comprehensive INTEGRAL active galactic nucleus (AGN) sample. It lists 272 AGN for which we have secure optical identifications, precise optical...

Clusters of galaxies are potentially important targets for indirect searches for dark matter (DM) annihilation. Here we reassess the detection prospects for annihilation in...

Machine learning, algorithms designed to extract empirical knowledge from data, can be used to classify data, which is one of the most common tasks in observational astronomy....

We present the detailed timing and spectral results obtained during the Swift observations of the TeV-detected blazar 1ES 1959+650 in 2016 August-2017 November. The source...

We present a search for spatial extension in high-latitude (|b|>5{deg}) sources in recent Fermi point source catalogs. The result is the Fermi High-Latitude Extended Sources...

The Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope provides an unprecedented opportunity to study gamma-ray blazars. To capitalize on this opportunity,...

We present the results of a systematic search and analysis of GRBs detected by the Astrorivelatore Gamma ad Immagini LEggero (AGILE) MiniCALorimeter (MCAL; 0.4-100MeV) over a...

Gamma-ray burst (GRB) afterglow emission can be observed from sub-TeV to radio wavelengths, though only 6.6% of observed GRBs present radio afterglows. We examine GRB radio...

Blazars show extreme observational properties that are due to the beaming effect with the jet being close to the line of sight. It was found that the observed luminosity is...

Distinct X-ray plateau and flare phases have been observed in the afterglows of gamma-ray bursts (GRBs), and most of them should be related to central engine activities. In this...

The Fermi-LAT unassociated sources represent some of the most enigmatic gamma-ray sources in the sky. Observations with the Swift-XRT and -UVOT telescopes have identified...

We present multiepoch, parsec-scale core brightness temperature observations of 447 active galactic nucleus (AGN) jets from the MOJAVE and 2cm Survey programs at 15GHz from 1994...

The uncharted territory of the high-redshift (z>~3) universe holds the key to understanding the evolution of quasars. In an attempt to identify the most extreme members of...

In this work, we exploit the luminosity of the broad-line region (BLR) for 50 Fermi blazars through matching the coordinates between the Sloan Digital Sky Survey catalog, Fermi...

The duration of a gamma-ray burst (GRB) is a key indicator of its physical origin, with long bursts perhaps associated with the collapse of massive stars and short bursts with...