Results 31 to 40 of about 220,311 (341)

Second AGILE catalogue of gamma-ray sources [PDF]

Astronomy & Astrophysics, 2019
Aims. We present the second AGILE–GRID catalogue (2AGL) ofγ-ray sources in the energy range 100 MeV–10 GeV.Methods. With respect to previous AGILE–GRID catalogues, the current 2AGL catalogue is based on the first 2.3 years of science data from the AGILE mission (the so-called pointing mode) and incorporates more data and several analysis improvements ...
A. Pellizzoni, L. Baroncelli, Francesco Longo, A. Giuliani, Alessio Aboudan, Fulvio Gianotti, Maura Pilia, A. Rappoldi, M. Trifoglio, M. Tavani, Fabrizio Lucarelli, Fabrizio Lucarelli, G. Piano, N. Parmiggiani, A. Argan, M. Giusti, S. Vercellone, A. W. Chen, C. Pittori, C. Pittori, Louis Antonelli, Andrea Bulgarelli, Paolo Giommi, P. W. Cattaneo, M. Cardillo, I. Donnarumma, I. Donnarumma, Alessio Trois, F. Verrecchia, F. Verrecchia, Valentina Fioretti, Andrea Zoli   +31 more
openaire   +5 more sources

A Search for Blazar-Like Radio-Loud Narrow-Line Seyfert 1 Galaxies

Galaxies, 2017
We report the results of an observational program to investigate the gamma-ray and optical variability properties of the vRL NLSY1 galaxies listed in the Yuan et al. sample. We have identified 17 members of the Yuan et al. sample possibly associated with
Hugh R. Miller, Jeremy D. Maune, Joseph R. Eggen, Clay S. Turner, Elizabeth C. Ferrara, Diana O. Gudkova, Amy M. Battles   +6 more
doaj   +1 more source

Near-infrared and gamma-ray monitoring of TANAMI gamma-ray bright sources [PDF]

Astronomy & Astrophysics, 2013
Spectral energy distribution and its variability are basic tools for understanding the physical processes operating in active galactic nuclei (AGN). In this paper we report the results of a one-year near infra red (NIR) and optical monitoring of a sample of 22 AGN known to be gamma-ray emitters, aimed at discovering correlations between optical and ...
Roberto Nesci, Roberto Nesci, Gino Tosti, Tapio Pursimo, Roopesh Ojha, Roopesh Ojha, Matthias Kadler   +6 more
openaire   +5 more sources

New stage in high-energy gamma-ray studies with GAMMA-400 after Fermi-LAT

EPJ Web of Conferences, 2017
Fermi-LAT has made a significant contribution to the study of high-energy gamma-ray diffuse emission and the observations of 3000 discrete sources. However, one third of all gamma-ray sources (both galactic and extragalactic) are unidentified, the data ...
Topchiev N.P., Galper A.M., Bonvicini V., Adriani O., Arkhangelskaja I.V., Arkhangelskiy A.I., Bakaldin A.V., Bobkov S.G., Boezio M., Dalkarov O.D., Egorov A.E., Gorbunov M.S., Gusakov Yu.V., Hnatyk B.I., Kadilin V.V., Kaplin V.A., Kheymits M.D., Korepanov V.E., Leonov A.A., Longo F., Mikhailov V.V., Mocchiutti E., Moiseev A.A., Moskalenko I.V., Naumov P.Yu., Picozza P., Runtso M.F., Serdin O.V., Sparvoli R., Spillantini P., Stozhkov Yu.I., Suchkov S.I., Taraskin A.A., Tavani M., Yurkin Yu.T., Zverev V.G.   +35 more
doaj   +2 more sources

Radioactive Ion Sources [PDF]

CERN Yellow Report CERN-2013-007, pp.331-349, 2014
This chapter provides an overview of the basic requirements for ion sources designed and operated in radioactive ion beam facilities. The facilities where these sources are operated exploit the isotope separation online (ISOL) technique, in which a target is combined with an ion source to maximize the secondary beam intensity and chemical element ...
arxiv   +1 more source

Do gamma-ray burst sources repeat? [PDF]

Monthly Notices of the Royal Astronomical Society, 1993
Following the discovery by Quashnock and Lamb (1993) of an apparent excess of $ $-ray burst pairs with small angular separations, we reanalyze the angular distribution of the bursts in the BATSE catalogue. We find that in addition to an excess of close pairs, there is also a comparable excess of antipodal bursts, i.e pairs of bursts separated by about
Ramesh Narayan, Tsvi Piran
openaire   +5 more sources

Chandra Observations of "The Antennae" Galaxies (NGC 4038/39): II. Detection and Analysis of Galaxian X-ray source [PDF]

Astrophys.J.Suppl. 142 (2002) 239-260, 2002
We report the detailed analysis of the X-ray properties of the discrete sources detected in a long (72 ks) \chandra ACIS-S observation of the Antennae galaxies. We detect 49 sources, down to a detection limit of ~ 10^{38} erg\s; 18 sources have Lx >10^{39} erg\s (Ultra Luminous X-ray sources; ULXs). Six of the 49 sources have an extended component. Two
arxiv   +1 more source

The genesis of morphologies in extended radio sources: X-shapes, off-axis distortions and giant radio sources [PDF]

Astrophys.J.695:156-170,2009, 2008
We examine relationships between the morphology in double radio sources and the radio-optical position angle offset--the relative orientation of the radio axis with respect to the major axis of the host galaxy. The study was done for a representative sample of radio sources: the nearby (redshift z < 0.5) 3CRR sources, and separately for samples of ...
arxiv   +1 more source

Precessing microblazars and unidentified gamma-ray sources [PDF]

Astronomy & Astrophysics, 2002
The recent discovery by Paredes et al. (2000) of a persistent microquasar that is positionally coincident with an unidentified gamma-ray source has open the possibility that other sources in the Third EGRET Catalog could be interpreted as microquasars as well.
Kaufman Bernadó, María Marina, Romero, Gustavo Esteban, Mirabel Miquele, Igor Felix   +2 more
openaire   +5 more sources

External Inverse-compton and Proton Synchrotron Emission from the Reverse Shock as the Origin of VHE Gamma Rays from the Hyper-bright GRB 221009A

The Astrophysical Journal Letters, 2023
The detection of the hyper-bright gamma-ray burst (GRB) 221009A enables us to explore the nature of the GRB emission and the origin of very high-energy gamma rays.
B. Theodore Zhang, Kohta Murase, Kunihito Ioka, Deheng Song, Chengchao Yuan, Péter Mészáros   +5 more
doaj   +1 more source