Related papers: Evidence for a second component in the high-energy…

Testing the Origin of High-Energy Cosmic Rays

Recent accurate measurements of cosmic-ray (CR) protons and nuclei by ATIC-2, CREAM, and PAMELA reveal: a) unexpected spectral hardening in the spectra of CR species above a few hundred GeV per nucleon, b) a harder spectrum of He compared…

High Energy Astrophysical Phenomena · Physics 2016-08-14 Andrey E. Vladimirov , Guðlaugur Jóhannesson , Igor V. Moskalenko , Troy A. Porter

Detection of Alpha Centauri at radio wavelengths: chromospheric emission and search for star-planet interaction

At radio wavelengths, solar-type stars emit thermal free-free and gyroresonance, gyrosynchrotron, and impulsive coherent emission. Thermal free-free emission originates at layers where the optical depth is close to unit, while high…

Solar and Stellar Astrophysics · Physics 2018-08-29 C. Trigilio , G. Umana , F. Cavallaro , C. Agliozzo , P. Leto , C. S. Buemi , A. Ingallinera , F. Bufano , S. Riggi

Resolving the innermost parsec of Centaurus A at mid-infrared wavelengths

We report the results of interferometric observations of Centaurus A with the MID-infrared Interferometer (MIDI) at ESO's VLTI telescope array. The interferometric measurements are spectrally resolved (R = 30) in the wavelength range 8 to…

Astrophysics · Physics 2009-11-13 K. Meisenheimer , K. R. W. Tristram , W. Jaffe , F. Israel , N. Neumayer , D. Raban , H. Röttgering , W. D. Cotton , U. Graser , Th. Henning , Ch. Leinert , B. Lopez , G. Perrin , A. Prieto

Observation of a spectral hardening in cosmic ray boron spectrum with the DAMPE space mission

Secondary cosmic ray fluxes are important probes of the propagation and interaction of high-energy particles in the Galaxy. Recent measurements of primary and secondary cosmic ray nuclei have revealed unexpected spectral features that…

High Energy Astrophysical Phenomena · Physics 2024-12-19 DAMPE Collaboration , F. Alemanno , C. Altomare , Q. An , P. Azzarello , F. C. T. Barbato , P. Bernardini , X. J. Bi , H. Boutin , I. Cagnoli , M. S. Cai , E. Casilli , E. Catanzani , J. Chang , D. Y. Chen , J. L. Chen , Z. F. Chen , Z. X. Chen , P. Coppin , M. Y. Cui , T. S. Cui , Y. X. Cui , I. De Mitri , F. de Palma , A. Di Giovanni , T. K. Dong , Z. X. Dong , G. Donvito , D. Droz , J. L. Duan , K. K. Duan , R. R. Fan , Y. Z. Fan , F. Fang , K. Fang , C. Q. Feng , L. Feng , J. M. Frieden , P. Fusco , M. Gao , F. Gargano , E. Ghose , K. Gong , Y. Z. Gong , D. Y. Guo , J. H. Guo , S. X. Han , Y. M. Hu , G. S. Huang , X. Y. Huang , Y. Y. Huang , M. Ionica , L. Y. Jiang , Y. Z. Jiang , W. Jiang , J. Kong , A. Kotenko , D. Kyratzis , S. J. Lei , W. H. Li , W. L. Li , X. Li , X. Q. Li , Y. M. Liang , C. M. Liu , H. Liu , J. Liu , S. B. Liu , Y. Liu , F. Loparco , M. Ma , P. X. Ma , T. Ma , X. Y. Ma , G. Marsella , M. N. Mazziotta , D. Mo , X. Y. Niu , A. Parenti , W. X. Peng , X. Y. Peng , C. Perrina , E. Putti-Garcia , R. Qiao , J. N. Rao , R. Sarkar , P. Savina , A. Serpolla , Z. Shangguan , W. H. Shen , Z. Q. Shen , Z. T. Shen , L. Silveri , J. X. Song , M. Stolpovskiy , H. Su , M. Su , H. R. Sun , Z. Y. Sun , A. Surdo , X. J. Teng , A. Tykhonov , J. Z. Wang , L. G. Wang , S. Wang , X. L. Wang , Y. F. Wang , Y. Wang , D. M. Wei , J. J. Wei , Y. F. Wei , D. Wu , J. Wu , S. S. Wu , X. Wu , Z. Q. Xia , E. H. Xu , H. T. Xu , J. Xu , Z. H. Xu , Z. L. Xu , Z. Z. Xu , G. F. Xue , H. B. Yang , P. Yang , Y. Q. Yang , H. J. Yao , Y. H. Yu , Q. Yuan , C. Yue , J. J. Zang , S. X. Zhang , W. Z. Zhang , Yan Zhang , Yi Zhang , Y. J. Zhang , Y. L. Zhang , Y. P. Zhang , Y. Q. Zhang , Z. Zhang , Z. Y. Zhang , C. Zhao , H. Y. Zhao , X. F. Zhao , C. Y. Zhou , Y. Zhu

Correlation of $\gamma$-ray and high-energy cosmic ray fluxes from the giant lobes of Centaurus A

The spectral energy distribution of giant lobes shows one main peak detected by the Wilkinson Microwave Anisotropy Probe at low energy of $10^{-5}$ eV and a faint $\gamma$-ray flux imaged by Fermi Large Area Telescope at energy $\geq$ 100…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Nissim Fraija

Limits on X-ray Polarization at the Core of Centaurus A as Observed with the Imaging X-ray Polarimetry Explorer

We present measurements of the polarization of X-rays in the $2-8 \thinspace \mathrm{keV}$ band from the nucleus of the radio galaxy Centaurus A (Cen A), using a 100ks observation from the Imaging X-ray Polarimetry Explorer (IXPE). Nearly…

High Energy Astrophysical Phenomena · Physics 2022-08-31 Steven R. Ehlert , Riccardo Ferrazzoli , Andrea Marinucci , Herman L. Marshall , Riccardo Middei , Luigi Pacciani , Matteo Perri , Pierre-Olivier Petrucci , Simonetta Puccetti , Thibault Barnouin , Stefano Bianchi , Ioannis Liodakis , Grzegorz Madejski , Fréderic Marin , Alan P. Marscher , Giorgio Matt , Juri Poutanen , Kinwah Wu , Iván Agudo , Lucio A. Antonelli , Matteo Bachetti , Luca Baldini , Wayne H. Baumgartner , Ronaldo Bellazzini , Stephen D. Bongiorno , Raffaella Bonino , Alessandro Brez , Niccolò Bucciantini , Fiamma Capitanio , Simone Castellano , Elisabetta Cavazzuti , Stefano Ciprini , Enrico Costa , Alessandra De Rosa , Ettore Del Monte , Laura Di Gesu , Niccolò Di Lalla , Alessandro Di Marco , Immacolata Donnarumma , Victor Doroshenko , Michal Dovčiak , Teruaki Enoto , Yuri Evangelista , Sergio Fabiani , Javier A. Garcia , Shuichi Gunji , Kiyoshi Hayashida , Jeremy Heyl , Wataru Iwakiri , Svetlana G. Jorstad , Vladimir Karas , Takao Kitaguchi , Jeffery J. Kolodziejczak , Henric Krawczynski , Fabio La Monaca , Luca Latronico , Simone Maldera , Alberto Manfreda , Francesco Massaro , Ikuyuki Mitsuishi , Tsunefumi Mizuno , Fabio Muleri , Michela Negro , C. -Y. Ng , Stephen L. O'Dell , Nicola Omodei , Chiara Oppedisano , Alessandro Papitto , George G. Pavlov , Abel L. Peirson , Melissa Pesce-Rollins , Maura Pilia , Andrea Possenti , Brian D. Ramsey , John Rankin , Ajay Ratheesh , Roger W. Romani , Carmelo Sgrò , Patrick Slane , Paolo Soffitta , Gloria Spandre , Toru Tamagawa , Fabrizio Tavecchio , Roberto Taverna , Yuzuru Tawara , Allyn F. Tennant , Nicholas E. Thomas , Francesco Tombesi , Alessio Trois , Sergey Tsygankov , Roberto Turolla , Jacco Vink , Martin C. Weisskopf , Fei Xie , Silvia Zane , James Rodi , Elisabeth Jourdain , Jean-Pierre Roques

Radio Synchrotron Emission from Secondary Leptons in the Vicinity of Sgr A*

A point-like source of ~TeV gamma-rays has recently been seen towards the Galactic center by HESS and other air Cerenkov telescopes. In recent work (Ballantyne et al. 2007), we demonstrated that these gamma-rays can be attributed to…

Astrophysics · Physics 2009-11-13 Roland M. Crocker , David Jones , David R. Ballantyne , Fulvio Melia

The spectral energy distribution of Centaurus A (NGC 5128) - A summary of all observations including all GCRO results -

Due to its proximity and its importance for the understanding of active galaxies and their active nuclei (AGN), Centaurus A has been observed frequently within the last 150 years in all accessible wavelength bands. Thus a wealth of data…

Astrophysics · Physics 2009-11-06 Helmut Steinle

Excess Hard X-ray Emission from the Obscured Low Luminosity AGN In the Nearby Galaxy M 51 (NGC 5194)

We observed the nearby galaxy M~51 (NGC 5194) with BeppoSAX. The X-ray properties of the nucleus below 10 keV are almost the same as the ASCA results regarding the hard component and the neutral Fe K$\alpha$ line, but the intensity is about…

Astrophysics · Physics 2009-11-06 Yasushi Fukazawa , Naoko Iyomoto , Aya Kubota , Yukari Matsumoto , Kazuo Makishima

Multi-epoch X-ray spectral analysis of Centaurus A: revealing new constraints on iron emission line origins

We conduct X-ray reverberation mapping and spectral analysis of the radio galaxy Centaurus A to uncover its central structure. We compare the light curve of the hard X-ray continuum from Swift Burst Alert Telescope observations with that of…

High Energy Astrophysical Phenomena · Physics 2025-02-12 Toshiya Iwata , Atsushi Tanimoto , Hirokazu Odaka , Aya Bamba , Yoshiyuki Inoue , Kouichi Hagino

Analysis of Fermi-LAT observations, UHECRs and neutrinos from the radio galaxy Centaurus B

Centaurus B (Cen B) is one of the closest and brightest radio-loud galaxy in the southern sky. This radio galaxy, proposed as a plausible candidate for accelerating ultra-high-energy cosmic rays (UHECRs), is near the highest-energy neutrino…

High Energy Astrophysical Phenomena · Physics 2019-09-04 N. Fraija , M. Araya , A. Galvan-Gamez , J. A. de Diego

Gamma-Ray Spectral Variability of Cygnus X-1

We have used observations from CGRO to study the variation in the MeV emission of Cygnus X-1 between its low and high X-ray states. These data provide a measurement of the spectral variability above 1 MeV. The high state MeV spectrum is…

Astrophysics · Physics 2009-11-06 M. L. McConnell , K. Bennett , H. Bloemen , W. Collmar , W. Hermsen , L. Kuiper , W. Paciesas , B. Phlips , J. Poutanen , J. M. Ryan , V. Schoenfelder , H. Steinle , A. W. Strong , A. A. Zdziarski

Anomalous Galactic Cosmic Rays in the Framework of AMS-02

The cosmic ray energy spectra of protons and helium nuclei, which are the most abundant components of cosmic radiation, exhibit a remarkable hardening at energies above one hundred GeV/nucleon. Recent data from AMS-02 confirms this feature…

High Energy Astrophysical Phenomena · Physics 2017-02-08 Behrouz Khiali , Sadakazu Haino , Jie Feng

Giant lobes of Centaurus A as seen in radio and gamma-ray images obtained with the Fermi-LAT and Planck satellites

The {\gamma}-ray data of Fermi-LAT on the giant lobes of Centaurus A are analysed together with the high frequency radio data obtained with the Planck satellite. The large {\gamma}-ray photon statistics, accumulated during seven years of…

High Energy Astrophysical Phenomena · Physics 2017-08-09 Xiao-na Sun , Rui-zhi Yang , Benjamin Mckinley , Felix Aharonian

Cygnus X-3: A variable petaelectronvolt gamma-ray source

We report the discovery of variable $\gamma$-rays up to petaelectronvolt from Cygnus X-3, an iconic X-ray binary. The $\gamma$-ray signal was detected with a statistical significance of approximately 10 $\sigma$ by the Large High Altitude…

High Energy Astrophysical Phenomena · Physics 2026-04-14 The LHAASO Collaboration , Zhen Cao , F. Aharonian , Y. X. Bai , Y. W. Bao , D. Bastieri , X. J. Bi , Y. J. Bi , W. Bian , J. Blunier , A. V. Bukevich , C. M. Cai , Y. Y. Cai , W. Y. Cao , Zhe Cao , J. Chang , J. F. Chang , E. S. Chen , G. H. Chen , H. K. Chen , L. F. Chen , Liang Chen , Long Chen , M. J. Chen , M. L. Chen , Q. H. Chen , S. Chen , S. H. Chen , S. Z. Chen , T. L. Chen , X. B. Chen , X. J. Chen , X. P. Chen , Y. Chen , N. Cheng , Q. Y. Cheng , Y. D. Cheng , M. Y. Cui , S. W. Cui , X. H. Cui , Y. D. Cui , B. Z. Dai , H. L. Dai , Z. G. Dai , Danzengluobu , Y. X. Diao , A. J. Dong , X. Q. Dong , K. K. Duan , J. H. Fan , Y. Z. Fan , J. Fang , J. H. Fang , K. Fang , C. F. Feng , H. Feng , L. Feng , S. H. Feng , X. T. Feng , Y. Feng , Y. L. Feng , S. Gabici , B. Gao , Q. Gao , W. Gao , W. K. Gao , M. M. Ge , T. T. Ge , L. S. Geng , G. Giacinti , G. H. Gong , Q. B. Gou , M. H. Gu , F. L. Guo , J. Guo , K. J. Guo , X. L. Guo , Y. Q. Guo , Y. Y. Guo , R. P. Han , O. A. Hannuksela , M. Hasan , H. H. He , H. N. He , J. Y. He , X. Y. He , Y. He , S. Hernández-Cadena , B. W. Hou , C. Hou , X. Hou , H. B. Hu , S. C. Hu , C. Huang , D. H. Huang , J. J. Huang , X. L. Huang , X. T. Huang , X. Y. Huang , Y. Huang , Y. Y. Huang , A. Inventar , X. L. Ji , H. Y. Jia , K. Jia , H. B. Jiang , K. Jiang , X. W. Jiang , Z. J. Jiang , M. Jin , S. Kaci , M. M. Kang , I. Karpikov , D. Khangulyan , D. Kuleshov , K. Kurinov , Cheng Li , Cong Li , D. Li , F. Li , H. B. Li , H. C. Li , Jian Li , Jie Li , K. Li , L. Li , R. L. Li , S. D. Li , T. Y. Li , W. L. Li , X. R. Li , Xin Li , Y. Li , Zhe Li , Zhuo Li , E. W. Liang , Y. F. Liang , S. J. Lin , B. Liu , C. Liu , D. Liu , D. B. Liu , H. Liu , J. Liu , J. L. Liu , J. R. Liu , M. Y. Liu , R. Y. Liu , S. M. Liu , W. Liu , X. Liu , Y. Liu , Y. Liu , Y. N. Liu , Y. Q. Lou , Q. Luo , Y. Luo , H. K. Lv , B. Q. Ma , L. L. Ma , X. H. Ma , I. O. Maliy , J. R. Mao , Z. Min , W. Mitthumsiri , Y. Mizuno , G. B. Mou , A. Neronov , K. C. Y. Ng , M. Y. Ni , L. Nie , L. J. Ou , Z. W. Ou , P. Pattarakijwanich , Z. Y. Pei , D. Y. Peng , J. C. Qi , M. Y. Qi , J. J. Qin , D. Qu , A. Raza , C. Y. Ren , D. Ruffolo , A. Sáiz , D. Savchenko , D. Semikoz , L. Shao , O. Shchegolev , Y. Z. Shen , X. D. Sheng , Z. D. Shi , F. W. Shu , H. C. Song , Yu. V. Stenkin , V. Stepanov , Y. Su , D. X. Sun , H. Sun , J. X. Sun , Q. N. Sun , X. N. Sun , Z. B. Sun , N. H. Tabasam , J. Takata , P. H. T. Tam , H. B. Tan , Q. W. Tang , R. Tang , Z. B. Tang , W. W. Tian , C. N. Tong , L. H. Wan , C. Wang , D. H. Wang , G. W. Wang , H. G. Wang , J. C. Wang , K. Wang , Kai Wang , Kai Wang , L. P. Wang , L. Y. Wang , L. Y. Wang , R. Wang , W. Wang , X. G. Wang , X. J. Wang , X. Y. Wang , Y. Wang , Y. D. Wang , Z. H. Wang , Z. X. Wang , Zheng Wang , D. M. Wei , J. J. Wei , Y. J. Wei , T. Wen , S. S. Weng , C. Y. Wu , H. R. Wu , Q. W. Wu , S. Wu , X. F. Wu , Y. S. Wu , S. Q. Xi , J. Xia , J. J. Xia , G. M. Xiang , D. X. Xiao , G. Xiao , Y. F. Xiao , Y. L. Xin , H. D. Xing , Y. Xing , D. R. Xiong , B. N. Xu , C. Y. Xu , D. L. Xu , R. F. Xu , R. X. Xu , S. S. Xu , W. L. Xu , L. Xue , D. H. Yan , T. Yan , C. W. Yang , C. Y. Yang , F. F. Yang , L. L. Yang , M. J. Yang , R. Z. Yang , W. X. Yang , Z. H. Yang , Z. G. Yao , X. A. Ye , L. Q. Yin , N. Yin , X. H. You , Z. Y. You , Q. Yuan , H. Yue , H. D. Zeng , T. X. Zeng , W. Zeng , X. T. Zeng , M. Zha , B. B. Zhang , B. T. Zhang , C. Zhang , H. Zhang , H. M. Zhang , H. Y. Zhang , J. L. Zhang , J. Y. Zhang , Li Zhang , P. F. Zhang , R. Zhang , S. R. Zhang , S. S. Zhang , S. Y. Zhang , W. Zhang , W. Y. Zhang , X. Zhang , X. P. Zhang , Yi Zhang , Yong Zhang , Z. P. Zhang , J. Zhao , L. Zhao , L. Z. Zhao , S. P. Zhao , X. H. Zhao , Z. H. Zhao , F. Zheng , T. C. Zheng , B. Zhou , H. Zhou , J. N. Zhou , M. Zhou , P. Zhou , R. Zhou , X. X. Zhou , X. X. Zhou , B. Y. Zhu , C. G. Zhu , F. R. Zhu , H. Zhu , K. J. Zhu , Y. C. Zou , X. Zuo , J. S. Wang

Discovery of an extra hard spectral component in the high-energy afterglow emission of GRB 130427A

The extended high-energy gamma-ray (>100 MeV) emission occurred after the prompt gamma-ray bursts (GRBs) is usually characterized by a single power-law spectrum, which has been explained as the afterglow synchrotron radiation. The afterglow…

High Energy Astrophysical Phenomena · Physics 2013-06-21 Pak-Hin Thomas Tam , Qing-Wen Tang , Shujing Hou , Ruo-Yu Liu , Xiang-Yu Wang

Ultrahigh-energy neutrinos as a probe of espresso-shear acceleration in jets of Centaurus A

It has been suggested that Centaurus A (Cen A) could make a contribution to the observed ultrahigh-energy cosmic-ray (UHECR) flux. We calculate the flux of astrophysical neutrinos produced by UHECRs accelerated in the jet of Cen A, a…

High Energy Astrophysical Phenomena · Physics 2025-06-30 Rostom Mbarek , Damiano Caprioli , Kohta Murase

Spectral Variability and iron line emission in the ASCA Observations of the Seyfert 1 Galaxy NGC4051

We present the results of an extensive analysis of the ``ASCA'' AO2 observation of the Seyfert 1 galaxy NGC4051. The target exhibits broadband [0.5--10 keV] variability by a factor $\sim 8$ on time scales $\sim 10^4 s$, with a typical…

Astrophysics · Physics 2015-06-24 Matteo Guainazzi , Tatehiro Mihara , Chiko Otani , Masaru Matsuoka

Hard-X-ray-selected Active Galactic Nuclei -- II. Spectral Energy Distributions in the 5-45 GHz domain

A wide-frequency radio study of Active Galactic Nuclei (AGN) is crucial to evaluate the intervening radiative mechanisms responsible for the observed emission and relate them with the underlying accretion physics. We present wide frequency…

High Energy Astrophysical Phenomena · Physics 2022-07-06 Francesca Panessa , Elia Chiaraluce , Gabriele Bruni , Daniele Dallacasa , Ari Laor , Ranieri D. Baldi , Ehud Behar , Ian McHardy , Francesco Tombesi , Fausto Vagnetti

High Energy Gamma-Ray Emission From PKS 1441+25

We present the $\gamma$-ray observations of the flat-spectrum radio quasar PKS 1441+25 (z=0.939), using the {\it Fermi} large Area Telescope data accumulated during January - December 2015. A $\gamma$-ray flare was observed in January 24,…

High Energy Astrophysical Phenomena · Physics 2017-07-26 N. Sahakyan , S. Gasparyan