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We report the detection of gamma-ray emission from PWN Kes 75 and PSR J1846-0258. Through modeling the spectral energy distribution incorporating the new Fermi-LAT data, we find the the observed gamma-ray emission is likely a combination of…

High Energy Astrophysical Phenomena · Physics 2023-02-01 Samayra M. Straal , Joseph D. Gelfand , Jordan L. Eagle

The H.E.S.S. telescope has recently detected the total electron-plus-positron ($e^+e^-$) flux up to 40 TeV, finding it to be a featureless and steeply-falling power-law above 1 TeV. This result is in stark tension with standard one-zone…

High Energy Astrophysical Phenomena · Physics 2025-03-25 Isabelle John , Tim Linden

We report the likely GeV $\gamma$-ray emission from the composite supernova remnant (SNR) COMP G327.1+1.1 by analyzing $\sim$12.2 years of the \textit{Fermi} Large Area Telescope (\textit{Fermi}-LAT) Pass 8 data. We found the features of…

High Energy Astrophysical Phenomena · Physics 2021-05-19 Yunchuan Xiang , Yi Xing , Zejun Jiang

The Cygnus Loop is a nearby supernova remnant (SNR) observed across the electromagnetic spectrum. With the analysis of 6 years of Fermi/LAT data we find that, what previous studies had considered a single source, consists of an extended…

High Energy Astrophysical Phenomena · Physics 2015-03-04 I. Reichardt , R. Terrier , J. West , S. Safi-Harb , E. de Oña-Wilhelmi , J. Rico

With almost 15 years of data taken by the Large Area Telescope (LAT) onboard the Fermi satellite we discovered an extended source of GeV emission in the region of the very-high-energy (TeV) source 1LHAASO J1945+2424. This TeV source is more…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Miguel Araya , J. A. Álvarez-Quesada

A TeV spectral break in the total flux of cosmic-ray electrons and positrons (CREs) at which the spectral power index softens from $\sim 3$ to $\sim 4$ has been observed by H.E.S.S. and recently confirmed by DAMPE with a high significance…

High Energy Astrophysical Phenomena · Physics 2021-06-16 Yu-Chen Ding , Nan Li , Chun-Cheng Wei , Yue-Liang Wu , Yu-Feng Zhou

The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This catalog was obtained using 80 months of data re-processed with Pass 8, the newest event-level analysis,…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-20 LAT Collaboration

The Fermi Large Area Telescope has provided the measurement of the high energy (20 GeV to 1 TeV) cosmic ray electrons and positrons spectrum with unprecedented accuracy. This measurement represents a unique probe for studying the origin and…

High Energy Astrophysical Phenomena · Physics 2019-08-14 Dario Grasso

The high sensitivity of the Fermi-LAT (Large Area Telescope) offers the first opportunity to study faint and extended GeV sources such as pulsar wind nebulae (PWNe). After one year of observation the LAT detected and identified three pulsar…

High Energy Astrophysical Phenomena · Physics 2011-01-28 The Fermi LAT Collaboration , Pulsar Timing Consortium

We present the analysis of Fermi Large Area Telescope (LAT) $\gamma$-ray observations of HB~21 (G89.0+4.7). We detect significant $\gamma$-ray emission associated with the remnant: the flux >100 MeV is…

High Energy Astrophysical Phenomena · Physics 2015-06-17 G. Pivato , J. Hewitt , L. Tibaldo , F. Acero , J. Ballet , T. J. Brandt , F. de Palma , F. Giordano , G. H. Janssen , G. Johannesson , D. A. Smith

We report the discovery of MeV-GeV gamma-ray emission by the Fermi-LAT positionally coincident with the TeV pulsar wind nebula (PWN) HESS~J1554-550 within the host supernova remnant (SNR) G327.1-1.1. The gamma-ray emission is point-like and…

High Energy Astrophysical Phenomena · Physics 2022-12-07 Jordan Eagle , Daniel Castro , Tea Temim , Jean Ballet , Patrick Slane , Joseph Gelfand , Matthew Kerr , Marco Ajello

The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to detect photons with energies from 20 MeV to > 300 GeV. The pre-launch response functions of the LAT were determined through…

High Energy Astrophysical Phenomena · Physics 2016-03-23 LAT Collaboration

At energies above a few TeV, no measurements of the cosmic-ray electron spectrum exist yet. By considering the similarity of air showers induced by electrons and gamma rays as seen by ground-based arrays, we use published limits on…

High Energy Astrophysical Phenomena · Physics 2009-12-03 Matthew D. Kistler , Hasan Yuksel

The Fermi-LAT telescope has measured the extragalactic gamma-ray background (EGB) generated by the ensemble of all extragalactic sources. The energy distribution of the EGB is well described as a power-law with a spectral index…

High Energy Astrophysical Phenomena · Physics 2020-09-09 Paolo Lipari

We have analysed the Fermi LAT data on the SNR G73.9+0.9. We have confirmed a previous detection of high-energy gamma-rays from this source at a high significance of $\simeq 12\sigma$. The observed spectrum shows a significant curvature,…

In this study, we report the likely GeV {\gamma}-ray emissions originating from the pulsar PSR J1849-0001's pulsar wind nebula (PWN) G32.64+0.53. Our analysis covers approximately 14.7 years of data from the Fermi Large Area Telescope…

High Energy Astrophysical Phenomena · Physics 2024-08-14 Yifan Xiao , Keyao Wu , Jun Fang

The cosmic-ray fluxes of electrons and positrons ($e^{\pm}$) are measured with high precision by the space-borne particle spectrometer AMS-02. To infer a precise interpretation of the production processes for $e^{\pm}$ in our Galaxy, it is…

High Energy Astrophysical Phenomena · Physics 2022-07-05 Luca Orusa , Mattia Di Mauro , Fiorenza Donato , Michael Korsmeier

Axion-like particles (ALPs) may be abundantly produced in core-collapse (CC) supernovae (SNe), hence the cumulative signal from all past SN events can create a diffuse flux peaked at energies of about 25~MeV. We improve upon the modeling of…

Observations of high energy gamma rays recently revealed a persistent source in spatial coincidence with the binary system Eta Carinae. Since modulation of the observed gamma-ray flux on orbital time scales has not been reported so far, an…

High Energy Astrophysical Phenomena · Physics 2012-08-14 K. Reitberger , O. Reimer , A. Reimer , M. Werner , K. Egberts , H. Takahashi

We report the discovery of a $\sim$ $3.4\degr$-wide region of high-energy emission in data from the \emph{Fermi} LAT satellite. The centroid of the emission is located in the Southern Hemisphere sky, a few degrees away from the plane of the…

High Energy Astrophysical Phenomena · Physics 2018-01-26 Miguel Araya