Results 61 to 70 of about 38,287 (310)

Source-count Distribution of Gamma-Ray Blazars [PDF]

Astrophysical Journal, 2020
With 10 years of operation and an exceptional data set, the Fermi-Large Area Telescope allows us to unveil the detailed composition of the extragalactic γ-ray sky above 100 MeV. In this paper, we derive the intrinsic source-count distribution (logN–logS)
L. Marcotulli, M. D. Mauro, M. Ajello
semanticscholar   +1 more source

Chasing the heaviest black holes of jetted Active Galactic Nuclei [PDF]

, 2010
We investigate the physical properties of the 10 blazars at redshift greater than 2 detected in the 3-years all sky survey performed by the Burst Alert Telescope (BAT) onboard the Swift satellite. We find that the jets of these blazars are among the most
Abdo, Abramowicz, Ajello, Baes, Bandara, Bassani, Bianchin, Bottacini, Brunthaler, Bryan, Cardelli, Cusumano, Donato, F. Haardt, F. Tavecchio, Ferrarese, Foschini, Fossati, Frank, G. Ghirlanda, G. Ghisellini, G. Pareschi, G. Tagliaferri, Ghisellini, Ghisellini, Ghisellini, Ghisellini, Ghisellini, Ghisellini, Gültekin, Haiman, Hook, J. Grindlay, Kalberla, L. Foschini, Li, M. Volonteri, Madau, Madau, Maraschi, Nandikotkur, Pizzella, Poole, Prochaska, R. Della Ceca, Romani, Roming, Sambruna, Sambruna, Schlegel, Shakura, Shapiro, Shen, Sheth, Stickel, Szuszkiewicz, Tavecchio, Thompson, Tueller, Volonteri, Volonteri, Watanabe, Worsley, Worsley, Yuan, Yuan   +65 more
core   +1 more source

Analysis of ∼106 Spiral Galaxies from Four Telescopes Shows Large‐Scale Patterns of Asymmetry in Galaxy Spin Directions

Advances in Astronomy, Volume 2022, Issue 1, 2022., 2022
The ability to collect unprecedented amounts of astronomical data has enabled the nomical data has enabled the stu scientific questions that were impractical to study in the pre‐information era. This study uses large datasets collected by four different robotic telescopes to profile the large‐scale distribution of the spin directions of spiral galaxies.
Lior Shamir, Sándor Frey
wiley   +1 more source

Identifying the 3FHL Catalog. VI. Results of the 2019 Gemini Optical Spectroscopy

The Astronomical Journal, 2023
Active galactic nuclei with their relativistic jets pointed toward the observer are a class of luminous gamma-ray sources commonly known as blazars. The study of this source class is essential to unveil the physical processes powering these extreme jets,
M. Rajagopal, L. Marcotulli, K. Labrie, S. Marchesi, M. Ajello   +4 more
doaj   +1 more source

Gaussian Process Modeling Fermi-LAT γ-Ray Blazar Variability: A Sample of Blazars with γ-Ray Quasi-periodicities [PDF]

, 2020
Blazar variability may be driven by stochastic processes. On the other hand, quasi-periodic oscillation (QPO) behaviors were recently reported to be detected in the Fermi-LAT data of blazars.
Shenbang Yang, D. Yan, Peng-fei Zhang, B. Dai, Li Zhang   +4 more
semanticscholar   +1 more source

Proton Synchrotron Gamma-Rays and the Energy Crisis in Blazars [PDF]

Astrophysical Journal, 2020
The origin of high-energy emission in blazars jets (i.e., leptonic versus hadronic) has been a longstanding matter of debate. Here, we focus on one variant of hadronic models where proton synchrotron radiation accounts for the observed steady γ-ray ...
I. Liodakis, M. Petropoulou
semanticscholar   +1 more source

Angular power spectrum of gamma-ray sources for GLAST: blazars and clusters of galaxies [PDF]

, 2006
Blazars, a beamed population of active galactic nuclei, radiate high-energy gamma-rays, and thus are a good target for the Gamma Ray Large Area Space Telescope (GLAST).
Ando, Shin'ichiro, Komatsu, Eiichiro, Narumoto, Takuro, Totani, Tomonori   +3 more
core   +2 more sources

The 3HSP catalogue of extreme and high-synchrotron peaked blazars [PDF]

Astronomy & Astrophysics, 2019
Aims. High-synchrotron peaked blazars (HSPs or HBLs) play a central role in very high-energy (VHE) γ-ray astronomy, and likely in neutrino astronomy. Currently, the largest compilation of HSP blazars, the 2WHSP sample, includes 1691 sources, but it is ...
Yu-Ling Chang, B. Arsioli, P. Giommi, P. Padovani, C. Brandt   +4 more
semanticscholar   +1 more source

Optical spectroscopy of blazars for the Cherenkov Telescope Array [PDF]

Astronomy & Astrophysics, 2020
Context. Blazars are the most numerous class of High Energy (HE; E about 50 MeV - few 100 GeV) and Very High Energy (VHE; E about 100 GeV - 10 TeV) gamma-ray emitters.
P. Goldoni, S. Pita, C. Boisson, W. Max-Moerbeck, E. Kasai, D. Williams, F. D’Ammando, V. Navarro-Aranguiz, M. Backes, U. D. Almeida, J. Becerra-González, G. Cotter, O. Hervet, J. Lenain, E. Lindfors, H. Sol, S. Wagner   +16 more
semanticscholar   +1 more source

Variability of Soft X-ray Spectral Shape in Blazars Observed by ROSAT [PDF]

, 2001
In paper 1 (Cheng et al. 2001) we have shown that the soft X-ray spectra of two types of Seyfert 1 galaxies statistically vary differently with increasing intensity.
Cappi M., Catanese M., Cheng L. P., Chiappeiti L., Fan J. H., Georganopoulos M., Ghisellini G., Giommi P., Jian-Yan Wei, Konigl A., Lin-Peng Cheng,Yong-Heng Zhao, Madejeski G. M., Mukherjee R., Padovani P., Perlman E. S., Romerto G. E., Scarpa R., Villata M., Wagner S. J., Xie G. Z., Xie G. Z.   +20 more
core   +2 more sources