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Multiwavelength study of quiescent states of MRK 421 with unprecedented hard x-ray coverage provided by NuSTAR in 2013
(IOP Publishing, 2016)
We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and ...
Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010
(EDP Sciences, 2015-05-27)
Context. Because of its proximity, Mrk 421 is one of the best sources on which to study the nature of BL Lac objects. Its proximity allows us to characterize its broadband spectral energy distribution (SED).
Aims. The ...
The Galway astronomical Stokes polarimeter: an all-Stokes optical polarimeter with ultra-high time resolution
(Springer Verlag, 2013-06-28)
Many astronomical objects emit polarised light, which can give information both about their source mechanisms, and about (scattering) geometry in their source regions. To date (mostly) only the linearly polarised components ...
The most powerful flaring activity from the NLSyl PMN J0948+0022
(Oxford University Press, 2015-01-21)
We report on multifrequency observations performed during 2012 December-2013 August of the first narrow-line Seyfert 1 galaxy detected in gamma-rays, PMN J0948+0022 (z = 0.5846). A y -ray flare was observed by the Large ...
Gamma-rays from the quasar PKS 1441+25: story of an escape
(2015-12-20)
Outbursts from gamma-ray quasars provide insights on the relativistic jets of active galactic nuclei and constraints on the diffuse radiation fields that fill the universe. The detection of significant emission above 100 ...
A search for pulsations from Geminga above 100 GeV with VERITAS
(American Astronomical Society, 2015-02-10)
We present the results of 71.6 hr of observations of the Geminga pulsar (PSR J0633+1746) with the VERITAS very-high-energy gamma-ray telescope array. Data taken with VERITAS between 2007 November and 2013 February were ...
VERITAS observations of the BL Lac object PG 1553+113
(American Astronomical Society, 2015-01-20)
We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560 GeV, is well described by a power law with a ...
VLT polarimetry observations of the middle-aged pulsar PSR B0656+14
(EDP Sciences, 2015-11-02)
Context. Optical polarisation measurements are key tests for different models of the pulsar magnetosphere. Furthermore, comparing the relative orientation of the phase-averaged linear polarisation direction and the pulsar ...
Circular polarization of synchrotron radiation in high magnetic fields
(Oxford University Press, 2015-04-17)
The general model for incoherent synchrotron radiation has long been known, with the first theory being published by Westfold in 1959 and continued by Westfold and Legg in 1968. When this model was first developed, it was ...
Understanding the changes of cone reflectance in adaptive optics flood illumination retinal images over three years
(Optical Society of America, 2016)
Although there is increasing interest in the investigation of cone reflectance variability, little is understood about its characteristics over long time scales. Cone detection and its automation is now becoming a fundamental ...