Zobrazeno 1 - 10
of 351
pro vyhledávání: '"Aldo Treves"'
Publikováno v:
The Astrophysical Journal, Vol 968, Iss 2, p 81 (2024)
Following the high activity of the γ -ray Fermi source 4FGL J0449.1+1121 (PKS 0446+112), possibly associated with a IceCube neutrino event IC-240105A, we obtained optical spectroscopy with the Gran Telescopio Canarias of the counterpart. We detect a
Externí odkaz:
https://doaj.org/article/c1c3d500ce024bba9ef901ac863b9349
Autor:
Riccardo Ottolina, Renato Falomo, Aldo Treves, Michela Uslenghi, Jari K. Kotilainen, Riccardo Scarpa, Emanuele Paolo Farina
Publikováno v:
Frontiers in Astronomy and Space Sciences, Vol 4 (2017)
The properties of circum-galactic gas in the halo of quasar host galaxies are investigated analyzing Mg II 2800 and C IV 1540 absorption-line systems along the line of sight close to quasars. We used optical spectroscopy of closely aligned pairs of q
Externí odkaz:
https://doaj.org/article/c1d0249507c84e2f89cc820c40e863aa
Publikováno v:
Frontiers in Astronomy and Space Sciences, Vol 4 (2017)
The Fermi Gamma-ray Observatory discovered about a thousand extragalactic sources emitting energy from 100 MeV to 100 GeV. The majority of these sources belong to the class of blazars characterized by a quasi-featureless optical spectrum (BL Lac Obje
Externí odkaz:
https://doaj.org/article/a1cc2eac41ad49c88a44818f148ad1d9
Autor:
Roberto Decarli, Renato Falomo, Jari K. Kotilainen, Tomi Hyvönen, Michela Uslenghi, Aldo Treves
Publikováno v:
Advances in Astronomy, Vol 2012 (2012)
The MBH-Mhost relation in quasars has been probed only in a limited parameter space, namely, at MBH∼109 M⊙ and Mhost∼1012 M⊙. Here we present a study of 26 quasars laying in the low-mass end of the relation, down to MBH∼107 M⊙. We selecte
Externí odkaz:
https://doaj.org/article/67ed9b14a72a4aa6bfc13babffc2fd88
Autor:
Simona Paiano, Renato Falomo, Aldo Treves, Paolo Padovani, Paolo Giommi, Riccardo Scarpa, Susanna Bisogni, Ester Marini
A correlation between astrophysical high-energy neutrinos and blazars has been suggested by various authors. In particular, a likely association between IceCube events and intermediate and high-energy peaked BL Lac objects has led to a sample of 47 o
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a492bd3590ffaa30155fdbee50f36117
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 510:2167-2172
The dynamics of isolated galaxy pairs represents an important tool to investigate the behavior of gravity in the low acceleration regime. Statistical analysis of a large sample of galaxy pairs led to the noticeable discovery of a region of preferred
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 508:6128-6141
We focus our analysis on 55 BL Lac objects with a hard Fermi gamma-ray spectrum, and for which a redshift or a lower limit to it has been determined by a previous study of ours. We extrapolate the spectral fits given by the 4FGL catalogue to the VHE
Examining a catalogue of isolated galaxy pairs, a preferred orbital intervelocity of ~150 km/s was recently reported. This discovery is difficult to reconcile with the expectations from Newtonian numerical simulations of cosmological structure format
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c074f7bdb961e80d3820958dc83c9227
http://arxiv.org/abs/2202.13766
http://arxiv.org/abs/2202.13766
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 497:94-108
We investigate the spectroscopic optical properties of gamma-ray sources detected with high significance above 50 GeV in the Third Catalog of Hard Fermi-LAT Sources (3FHL) and that are good candidates as TeV emitters. We focus on the 91 sources that
Based on a 20-year-long multiband observation of its light-curve, it was conjectured that the quasar SDSSJ025214.67-002813.7 has a periodicity of ~4.4 years. These observations were acquired at a highly irregular sampling rate and feature long interv
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::2bea5a450c24b0d93d9c11ff87c8f296