334 citations · 1.6k across the 24 of their papers we have counts for
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X-ray and multiwavelength polarization of Mrk 501 from 2022 to 2023
Chien-Ting J. Chen, Ioannis Liodakis, Riccardo Middei +143
We present multiwavelength polarization measurements of the luminous blazar Mrk~501 over a 14-month period. The 2--8 keV X-ray polarization was measured with the Imaging X-ray Pola…
Evidence of jet activity from the secondary black hole in the OJ287 binary system
Mauri J. Valtonen, Staszek Zola, Alok C. Gupta +29
We report the study of a huge optical intraday flare on November 12, 2021, at 2 am UT, in the blazar OJ287. In the binary black hole model it is associated with an impact of the se…
Observations of Low and Intermediate Spectral Peak Blazars with the Imaging X-ray Polarimetry Explorer
Herman L. Marshall, Ioannis Liodakis, Alan P. Marscher +145
We present X-ray polarimetry observations from the Imaging X-ray Polarimetry Explorer (IXPE) of three low spectral peak and one intermediate spectral peak blazars, namely 3C 273, 3…
X-ray Polarization Observations of BL Lacertae
Riccardo Middei, Ioannis Liodakis, Matteo Perri +143
Blazars are a class of jet-dominated active galactic nuclei with a typical double-humped spectral energy distribution. It is of common consensus the Synchrotron emission to be resp…
Polarized Blazar X-rays imply particle acceleration in shocks
Ioannis Liodakis, Alan P. Marscher, Iván Agudo +125
Most of the light from blazars, active galactic nuclei with jets of magnetized plasma that point nearly along the line of sight, is produced by high-energy particles, up to $\sim 1…
Polarized x-rays constrain the disk-jet geometry in the black hole x-ray binary Cygnus X-1
Henric Krawczynski, Fabio Muleri, Michal Dovčiak +111
A black hole x-ray binary (XRB) system forms when gas is stripped from a normal star and accretes onto a black hole, which heats the gas sufficiently to emit x-rays. We report a po…
Black hole spin-orbit misalignment in the X-ray binary MAXI J1820+070
Juri Poutanen, Alexandra Veledina, Andrei V. Berdyugin +10
The observational signatures of black holes in x-ray binary systems depend on their masses, spins, accretion rate and the misalignment angle between the black hole spin and the orb…
A luminous and isolated gamma-ray flare from the blazar B2 1215+30
VERITAS Collaboration, A. U. Abeysekara, S. Archambault +84
B2 1215+30 is a BL Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes, and subsequently confirmed by the VERITAS observatory with…
Optical and Radio variability of the Northern VHE gamma-ray emitting BL Lac objects
E. J. Lindfors, T. Hovatta, K. Nilsson +9
We compare the variability properties of very high energy gamma-ray emitting BL Lac objects in the optical and radio bands. We use the variability information to distinguish multip…
Primary black hole spin in OJ287 as determined by the General Relativity centenary flare
M. J. Valtonen, S. Zola, S. Ciprini +87
OJ287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts which are predictable in a binary black hole model. The model predicted a majo…
Precursor flares in OJ 287
P. Pihajoki, M. Valtonen, S. Zola +19
We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain th…
The structure and emission model of the relativistic jet in the quasar 3C 279 inferred from radio to high-energy gamma-ray observations in 2008-2010
M. Hayashida, G. M. Madejski, K. Nalewajko +90
We present time-resolved broad-band observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during the first two years of the Fermi Gamma-ray Space Tel…
The brightest gamma-ray flaring blazar in the sky: AGILE and multi-wavelength observations of 3C 454.3 during November 2010
S. Vercellone, E. Striani, V. Vittorini +84
Since 2005, the blazar 3C 454.3 has shown remarkable flaring activity at all frequencies, and during the last four years it has exhibited more than one gamma-ray flare per year, be…
The first Fermi multifrequency campaign on BL Lacertae: characterizing the low-activity state of the eponymous blazar
A. A. Abdo
We report on observations of BL Lacertae during the first 18 months of Fermi-LAT science operations and present results from a 48-day multifrequency coordinated campaign from 2008…
WEBT multiwavelength monitoring and XMM-Newton observations of BL Lacertae in 2007-2008. Unveiling different emission components
C. M. Raiteri, M. Villata, A. Capetti +8
In 2007-2008 we carried out a new multiwavelength campaign of the Whole Earth Blazar Telescope (WEBT) on BL Lacertae, involving three pointings by the XMM-Newton satellite, to stud…