Results 61 to 70 of about 7,472 (181)

Relativistic Jets in Gamma-Ray-Emitting Narrow-Line Seyfert 1 Galaxies

Galaxies, 2019
Before the launch of the Fermi Gamma-ray Space Telescope satellite only two classes of active galactic nuclei (AGN) were known to generate relativistic jets and thus to emit up to the γ -ray energy range: blazars and radio galaxies, both hosted
Filippo D’Ammando
doaj   +1 more source

On the Gamma-Ray Emission of the Andromeda Galaxy M31

The Astrophysical Journal Letters, 2023
Using the γ -ray data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (Fermi) for ∼14 yr, we examine the high-energy emission emanating from the center of the Andromeda galaxy M31.
Yi Xing, Zhongxiang Wang, Dong Zheng, Jie Li   +3 more
doaj   +1 more source

Pre-burst events of gamma-ray bursts with light speed variation

Physics Letters B, 2021
Previous researches on high-energy photon events from gamma-ray bursts (GRBs) suggest a light speed variation v(E)=c(1−E/ELV) with ELV=3.6×1017 GeV, together with a pre-burst scenario that hight-energy photons come out about 10 seconds earlier than low ...
Jie Zhu, Bo-Qiang Ma
doaj   +1 more source

2‐D Speed Profile of Negative Cloud‐to‐Ground Lightning Flashes With TGF Emissions

Journal of Geophysical Research: Atmospheres, Volume 130, Issue 15, 16 August 2025.
Abstract We present the two‐dimensional (2‐D) speed profile of six stepped leaders with terrestrial gamma‐ray flashes (TGFs) (observed in 2021 (Abbasi et al., 2024, https://doi.org/10.1029/2024jd041260) and 2022 (Kieu et al., 2024, https://doi.org/10.1029/2024jd041720)) and 94 stepped leaders without TGFs (detected in 2021, 2022, 2023, and 2024). These
Ivan T. Cruz, Marcelo M. F. Saba, Rasha U. Abbasi, José Claudio O. Silva, Gabriel S. Diniz, Ny T. Kieu, Diego R. R. da Silva, Tagianne P. da Silva, Paola B. Lauria   +8 more
wiley   +1 more source

Likely Detection of γ-Ray Pulsations of PSR J1717+4308A in NGC 6341 and Implication of the γ-Ray Millisecond Pulsars in Globular Clusters

The Astrophysical Journal, 2023
We report our analysis results for the globular cluster (GC) NGC 6341 (M92), as a millisecond pulsar (MSP) J1717+4308A has recently been reported found in this GC.
Pengfei Zhang, Yi Xing, Zhongxiang Wang, Wei Wu, Zhangyi Chen   +4 more
doaj   +1 more source

Multi-wavelength behaviour of the radio galaxy SBS 1343+537: γ-ray flaring activity discovered by Fermi-LAT and coordinated Swift and SRT observations

Astronomy & Astrophysics
The SBS 1343+537 radio galaxy has a kiloparsec-scale radio jet, and complex kiloparsec-scale morphology. Although its classification is still uncertain, in literature it is indicated as a possible Fanaroff-Riley type I (FR-I) object with extended wings ...
Casaburo Fausto, Ciprini Stefano, Bartolini Chiara, Carboni Giuseppe, Teddy Cheung C. C., Egron Elise, Gasparrini Dario, Giacchino Federica, Iacolina Maria Noemi, Marchili Nicola, Pellizzoni Alberto, Principe Giacomo, Tombesi Francesco, Tramacere Andrea, Verrecchia Francesco   +14 more
doaj   +1 more source

The Fermi GBM and LAT follow-up of GW150914

EPJ Web of Conferences, 2017
As the first detection of Gravitation Wave (GW) event arising from the coalescence of two stellar-mass Black Holes (BH) was announced by LIGO, a new era for astronomy began.
Bissaldi E., Connaughton V., Omodei N., Burns E., Goldstein A., Vianello G.   +5 more
doaj   +1 more source

A Review of Ga₂O₃ Heterojunctions for Deep‐UV Photodetection: Current Progress, Methodologies, and Challenges

Advanced Electronic Materials, Volume 11, Issue 9, June 2025.
This paper provides a comprehensive review of the existing literature related to the fundamentals of gallium oxide (Ga2O3), growth methods, substrates, and particularly a focused examination of Ga2O3‐based heterojunctions. Particular attention has also been given to the state‐of‐the‐art Ga2O3‐based heterojunctions for photodetectors. The key challenges
Alfred Moore, Saqib Rafique, Ciaran Llewelyn, Dan Lamb, Lijie Li   +4 more
wiley   +1 more source

Unraveling the Physics of Quasar Jets: Optical Polarimetry and Implications for the X-ray Emission Process

Galaxies, 2020
Since the launch of Chandra twenty years ago, one of the greatest mysteries surrounding Quasar Jets is the production mechanism for their extremely high X-ray luminosity. Two mechanisms have been proposed. In the first view, the X-ray emission is inverse-
Eric S. Perlman, Devon Clautice, Sayali Avachat, Mihai Cara, William B. Sparks, Markos Georganopoulos, Eileen Meyer   +6 more
doaj   +1 more source

Exploring the extreme universe with the Fermi Gamma-Ray Space Telescope [PDF]

Physics Today, 2012
The Fermi orbiter, mapping the entire gamma-ray sky every three hours, monitors the cosmos for high-energy phenomena both fleeting and enduring.
David J. Thompson, Seth W. Digel, Judith L. Racusin   +2 more
openaire   +1 more source