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Related papers: The Fermi Bubbles: Supersonic AGN Jets with Anisot…

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The ~200 HI clouds observed to be entrained in the Fermi Bubble wind show a trend of increasing maximum |VLSR| with Galactic latitude. We analyze previous observations and present new data from the Green Bank Telescope that rule out…

Astrophysics of Galaxies · Physics 2020-01-15 Felix J. Lockman , Enrico M. Di Teodoro , N. M. McClure-Griffiths

The Large Area Telescope on board the Fermi Gamma-ray Space Telescope has collected the largest ever sample of high-energy cosmic-ray electron and positron events since the beginning of its operation. Potential anisotropies in the arrival…

High Energy Astrophysical Phenomena · Physics 2017-03-06 LAT Collaboration

Active Galactic Nuclei (AGN) sources feature supermassive black holes that launch relativistic plasma jets. They are key $\gamma$-ray sources providing a unique laboratory for studying extreme particle acceleration and plasma physics.…

High Energy Astrophysical Phenomena · Physics 2026-02-03 Luana Passos-Reis , Elisabete M. de Gouveia Dal Pino , Tarek Hassan , Santiago Pita , Alberto Domínguez

Jet feedback from active galactic nuclei (AGN) is one of the most promising mechanisms for suppressing cooling flows in cool-core clusters. However, the composition of AGN jets and bubbles remains uncertain; they could be thermally…

High Energy Astrophysical Phenomena · Physics 2023-01-25 Yen-Hsing Lin , H. -Y. Karen Yang , Ellis R. Owen

Jetted Active Galactic Nuclei (AGN) exhibit variability across a wide range of time scales. Traditionally, this variability can often be modeled well as a stochastic process. However, in certain cases, jetted AGN variability displays…

High Energy Astrophysical Phenomena · Physics 2025-01-03 P. Penil , A. Domínguez , S. Buson , M. Ajello , S. Adhikari , A. Rico

Super-bubbles are shells in the interstellar medium produced by the simultaneous explosions of many supernova remnants. The solutions of the mathematical diffusion and of the Fourier expansion in 1D, 2D and 3D were deduced in order to…

Astrophysics · Physics 2011-09-20 Lorenzo Zaninetti

The Fermi Gamma-ray Space Telescope, a key mission in multiwavelength and multimessenger studies, has been surveying the gamma-ray sky from its low-Earth orbit since 2008. Its two scientific instruments, the Gamma-ray Burst Monitor (GBM)…

High Energy Astrophysical Phenomena · Physics 2023-04-05 David J. Thompson , Colleen A. Wilson-Hodge

Quasars with flat radio spectra and one-sided, arc-second scale, ~100 mJy GHz radio jets are found to have similar scale X-ray jets in about 60% of such objects, even in short 5 to 10 ks Chandra observations. Jets emit in the GHz band via…

High Energy Astrophysical Phenomena · Physics 2020-03-04 Daniel A. Schwartz

Gamma-ray bursts (GRBs) are widely suggested as potential sources of ultrahigh-energy cosmic rays (UHECRs). The kinetic energy of the jets dissipates, leading to the production of an enormous amount of $\gamma$-ray photons and possibly also…

High Energy Astrophysical Phenomena · Physics 2025-01-17 Xing-Fu Zhang , Ruo-Yu Liu , Hai-Ming Zhang , Yi-Yun Huang , B. Theodore Zhang , Xiang-Yu Wang

Recently the Fermi-LAT data have revealed two gamma-ray emitting bubble-shaped structures at the Galactic center. If the observed gamma rays have hadronic origin (collisions of accelerated protons), the bubbles must emit high energy…

High Energy Astrophysical Phenomena · Physics 2012-07-06 Cecilia Lunardini , Soebur Razzaque

We analyze the gamma-ray sky at energies of 0.5 to 50 GeV using the undecimated wavelet transform on the sphere. Focusing on the inner $60^{\circ} \times 60^{\circ}$ of the sky, we identify and characterize four separate residuals beyond…

High Energy Astrophysical Phenomena · Physics 2018-08-15 Bhaskaran Balaji , Ilias Cholis , Patrick J. Fox , Samuel D. McDermott

The discovery by the Large Area Telescope on board Fermi of variable gamma-ray emission from radio-loud narrow-line Seyfert 1 (NLSy1) galaxies revealed the presence of a possible third class of Active Galactic Nuclei (AGN) with relativistic…

High Energy Astrophysical Phenomena · Physics 2019-08-15 F. D'Ammando , M. Orienti , J. Finke , J. Larsson , M. Giroletti , C. M. Raiteri

A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E^-2 spectrum from two large areas, spanning 50{\deg} above and below the Galactic centre (the "Fermi…

High Energy Astrophysical Phenomena · Physics 2012-11-28 The KM3NeT Collaboration

Over the past 16 years, the Fermi Large Area Telescope (LAT) has significantly advanced our view of the GeV gamma-ray sky, yet several key questions remain - such as the composition of the isotropic gamma-ray background, the origin of the…

High Energy Astrophysical Phenomena · Physics 2025-05-07 Christopher Eckner , Noemi Anau Montel , Florian List , Francesca Calore , Christoph Weniger

We present the analysis of 9.7 years Fermi-LAT data of the middle-aged supernova remnant W44 and the massive molecular gas complex that surrounds it. We derived a high-quality spectral energy distribution of gamma-radiation of the shell…

High Energy Astrophysical Phenomena · Physics 2020-07-10 Giada Peron , Felix Aharonian , Sabrina Casanova , Roberta Zanin , Carlo Romoli

The origin of the extended X-ray emission in the large-scale jets of active galactic nuclei (AGNs) poses challenges to conventional models of acceleration and emission. Although the electron synchrotron radiation is considered the most…

High Energy Astrophysical Phenomena · Physics 2017-06-28 Ruo-Yu Liu , F. M. Rieger , F. A. Aharonian

It is widely accepted that feedback from active galactic nuclei (AGN) plays a key role in the evolution of gas in groups and clusters of galaxies. Unequivocal evidence comes from quasi-spherical X-ray cavities observed near cluster centers…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Fulai Guo , William G. Mathews

The diffuse Galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray…

High Energy Astrophysical Phenomena · Physics 2019-08-13 T. A. Porter

Considerable asymmetries in jets from active galactic nuclei (AGN) and associated double radio sources can be caused by an inhomogeneous interstellar medium of the host galaxy. These asymmetries can easily be estimated by 1D propagation…

Astrophysics of Galaxies · Physics 2014-07-22 Volker Gaibler

Context: Few Active Galactic Nuclei (AGN) reveal a double sided jet system. However, these are crucial to understand basic physical properties of extragalactic jets. Aims: We address the questions whether jets in AGN are symmetric in…

Astrophysics of Galaxies · Physics 2019-02-27 A. -K. Baczko , R. Schulz , M. Kadler , E. Ros , M. Perucho , C. M. Fromm , J. Wilms