593 citations · 28.6k across the 519 of their papers we have counts for
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Spectral Energy Distribution of Markarian 501: Quiescent State vs. Extreme Outburst
The VERITAS Collaboration, V. A. Acciari, T. Arlen +225
The very high energy (VHE; E > 100 GeV) blazar Markarian 501 has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical pro…
The transition between BL Lac objects and Flat Spectrum Radio Quasars
G. Ghisellini, F. Tavecchio, L. Foschini +1
We study the BL Lac objects detected in the one year all sky survey of the Fermi satellite, with a energy spectral slope alpha_gamma in the [0.1-100 GeV] band greater than 1.2. In…
Insights Into the High-Energy Gamma-ray Emission of Markarian 501 from Extensive Multifrequency Observations in the Fermi Era
LAT collaboration, A. A. Abdo et al., the MAGIC collaboration +6
We report on the gamma-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average LAT gamma-ray spectrum of Mrk 501 can be well descr…
INTEGRAL observations of the GeV blazar PKS1502+106 and of the hard X-ray bright Seyfert Galaxy Mkn841
E. Pian, P. Ubertini, A. Bazzano +15
Extragalactic nuclear activity is best explored with observations at high energies, where the most extreme flux and spectral variations are expected to occur, witnessing changes in…
The first gamma-ray outburst of a Narrow-Line Seyfert 1 Galaxy: the case of PMN J0948+0022 in July 2010
L. Foschini, G. Ghisellini, Y. Y. Kovalev +24
We report on a multiwavelength campaign on the radio-loud Narrow-Line Seyfert 1 (NLS1) Galaxy PMN J0948+0022 (z=0.5846) performed in 2010 July-September and triggered by a high-ene…
Observations of the Blazar 3C 66A with the MAGIC Telescopes in Stereoscopic Mode
The MAGIC Collaboration, J. Aleksić, L. A. Antonelli +153
We report new observations of the intermediate-frequency peaked BL Lacertae object 3C 66A with the MAGIC telescopes. The data sample we use were taken in 2009 December and 2010 Jan…
High redshift Fermi blazars
G. Ghisellini, G. Tagliaferri, L. Foschini +6
With the release of the first year Fermi catalogue, the number of blazars detected above 100 MeV lying at high redshift has been largely increased. There are 28 blazars at z>2 in t…
Compton rockets and the minimum power of relativistic jets
G. Ghisellini, F. Tavecchio
The power of a relativistic jet depends on the number of leptons and protons carried by the jet itself. We have reasons to believe that powerful gamma-ray flat spectrum radio sourc…
Detection of very high energy gamma-ray emission from the Perseus cluster head-tail galaxy IC 310 by the MAGIC telescopes
MAGIC Collaboration, J. Aleksić, L. A. Antonelli +151
We report on the detection with the MAGIC telescopes of very high energy gamma-rays from IC 310, a head-tail radio galaxy in the Perseus galaxy cluster, observed during the interva…
Relativistic jets in Narrow-Line Seyfert 1
L. Foschini, E. Angelakis, G. Bonnoli +20
Narrow-Line Seyfert 1 (NLS1) class of active galactic nuclei (AGNs) is generally radio-quiet, but a small percent of them are radio-loud. The recent discovery by Fermi/LAT of high-…
Extreme TeV blazars and the intergalactic magnetic field
F. Tavecchio, G. Ghisellini, G. Bonnoli +1
We study the four BL Lac objects (RGB J0152+017, 1ES 0229+200, 1ES 0347-121 and PKS 0548-322) detected in the TeV band but not present in the 1FGL catalogue of the Fermi/Large Area…
MAGIC Upper Limits for two Milagro-detected, Bright Fermi Sources in the Region of SNR G65.1+0.6
J. Aleksić, L. A. Antonelli, P. Antoranz +144
We report on the observation of the region around supernova remnant G65.1+0.6 with the stand-alone MAGIC-I telescope. This region hosts the two bright GeV gamma-ray sources 1FGL J1…
The radio/gamma-ray connection in Fermi-blazars
G. Ghirlanda, G. Ghisellini, F. Tavecchio +2
We study the correlation between the gamma-ray flux F_g, averaged over the first 11 months of Fermi survey and integrated above 100 MeV, and the radio flux density (F_r at 20 GHz)…
Magic constraints on Gamma-ray emission from Cygnus X-3
J. Aleksić, L. A. Antonelli, P. Antoranz +156
Cygnus X-3 is a microquasar consisting of an accreting compact object orbiting around a Wolf-Rayet star. It has been detected at radio frequencies and up to high-energy gamma rays…
MAGIC observation of the GRB080430 afterglow
MAGIC Collaboration, J. Aleksić, H. Anderhub +151
Context: Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of gam…
Suzaku Observations of Luminous Quasars: Revealing the Nature of High-Energy Blazar Emission in Quiescent States
LAT Collaboration, A. A. Abdo, F. Tavecchio +5
We present the results from the Suzaku X-ray observations of five flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243, PKS1127-145, PKS1510-089 and 3C 454.3. All the…
High-frequency-peaked BL Lacertae objects as spectral candles to measure the Extragalactic Background Light in the Fermi and air Cherenkov telescopes era
Nijil Mankuzhiyil, Massimo Persic, Fabrizio Tavecchio
The Extragalactic Background Light (EBL) is the integrated light from all the stars that have ever formed, and spans the IR-UV range. The interaction of very-high-energy (VHE: E>10…
Constraining the location of the emitting region in Fermi blazars through rapid gamma-ray variability
F. Tavecchio, G. Ghisellini, G. Bonnoli +1
We consider the 1.5 years Fermi Large Area Telescope light curves (E > 100 MeV) of the flat spectrum radio quasars 3C 454.3 and PKS 1510-089, which show high activity in this perio…
Does the gamma-ray flux of the blazar 3C 454.3 vary on sub-hour timescales?
L. Foschini, G. Tagliaferri, G. Ghisellini +3
In the early days of April 2010, the blazar 3C 454.3 (z=0.859) underwent a strong gamma-ray outburst, reaching fluxes (E > 100 MeV) in excess of 10^-5 ph cm^-2 s^-1. The Fermi Gamm…
The intergalactic magnetic field constrained by Fermi/LAT observations of the TeV blazar 1ES 0229+200
F. Tavecchio, G. Ghisellini, L. Foschini +3
TeV photons from blazars at relatively large distances, interacting with the optical-IR cosmic background, are efficiently converted into electron-positron pairs. The produced pair…
Search for an extended VHE gamma-ray emission from Mrk 421 and Mrk 501 with the MAGIC Telescope
MAGIC Collaboration, J. Aleksić, L. A. Antonelli +148
Context: Part of the very high energy -ray radiation coming from extragalactic sources is absorbed through the pair production process on the extragalactic background light phot…
Constraining blazar distances with combined Fermi and TeV data: an empirical approach
E. Prandini, G. Bonnoli, L. Maraschi +2
We discuss a method to constrain the distance of blazars with unknown redshift using combined observations in the GeV and TeV regimes. We assume that the VHE spectrum corrected for…
Correlation of Fermi-LAT sources with the AT20GHz radio survey
G. Ghirlanda, G. Ghisellini, F. Tavecchio +1
We cross correlate the Fermi 11 months survey catalogue (1FGL) with the 20 GHz Australia Telescope Compact Array radio survey catalogue (AT20G) composed by 5890 sources at declinat…
The gamma-ray brightest days of the blazar 3C 454.3
G. Bonnoli, G. Ghisellini, L. Foschini +2
In the first week of December 2009, the blazar 3C 454.3 became the brightest high energy source in the sky. Its photon flux reached and surpassed the level of 1e-5 ph/cm2/s above 1…