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Showing 1 to 14 of 14 for “"blazar"”.
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The optical polarization variability of the blazar PKS 2155 304
Blazars are some of the most energetic and variable objects in the universe. Blazar emission has been detected across the electromagnetic spectrum and exhibits variability on a wide range of timescales, from minutes to years. The observed emission is Doppler boosted and dominated by non-thermal …
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Physics from Time Variability of the VHE Blazar PKS 2155-304
Blazars are the principal extragalactic sources of very high energy gamma-ray emission in the Universe. These objects constitute a sub-class of Active Galactic Nuclei whose emission is dominated by Doppler boosted non-thermal radiation from plasma outflowing at relativistic speeds from the central …
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Analysis of variable VHE gamma-ray emission from the hard spectrum blazar 1ES 1218+304
… energy gamma-ray emission from the hard spectrum blazar 1ES 1218+304. The data were collected during the 2008/09 observing season by the VERITAS observatory, an array of four atmospheric Cherenkov telescopes in Southern Arizona. This work describes the development of a set of analysis tools …
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Observational Properties of Gigaelectronvolt-Teraelectronvolt Blazars and the Study of the Teraelectronvolt Blazar RBS 0413 with VERITAS
Blazars are active galactic nuclei with a relativistic jet directed towards the observer's line of sight. Characterization of the non-thermal continuum emission originating from the blazar jet is currently an essential question in high-energy astrophysics. A blazar spectral energy distribution …
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Multifrequency observations of blazars
Blazars are a class of active galactic nuclei (AGN). Active galaxies are those that host compact sources of non-thermal radiation in their nuclear regions and are usually classified as being radio-loud or radio-quiet. The nature of the central source is ullcertain, but arguments based on energy …
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Probabilistic methods for radio interferometry data analysis
… VLBI Network (EVN) observation of the flaring blazar CGRaBS J0809+5341, to ascertain the presence of a jet emanating from its core, taking into account the imperfections in the station gain calibration performed on the data, especially on the longest baselines, prior to our analysis. We find …
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Collecting heat during the day, observing the sky at night : the use of a heliostat field near Almeria to search for cosmic gamma rays
… sources, among them the Crab nebula, the blazar Markarian 421 and the gamma-ray burst GRB010222. Evidence for a gamma-ray flux from the direction of the Crab pulsar and Markarian 421 was found, proving the feasibility of solar arrays for the observation of gamma-ray sources.
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Robotic Polarimetry of Blazars
… photometry of a sample of 20 gamma-ray bright blazars were combined with Fermi gamma-ray space telescope data and were used to explore possible correlations and thus probe the emission sites in the jet. We found that optical and gamma-ray fluxes had strong, positive correlations. This suggests …
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Instructional Coaches' Perceptions of Principal Support in a K-12 Public School Division
… and Pak, 2017; Knight and Cornett, 2007; Kraft, Blazar, and Hogan, 2019; Showers and Joyce, 1996). The purpose of this study was to identify instructional coaches' perceptions of principal support and the factors that contribute to those perceptions. The study aimed to address the following …
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SEARCH FOR GAMMA-RAY COUNTERPARTS OF GRAVITATIONAL WAVE EVENTS AND OTHER TRANSIENT SIGNALS WITH HAWC
… detected by IceCube to be associated with the blazar TXS 0506+056. Both demonstrate the potential of using multiple types of probes to study an astrophysical source. The High-Altitude Water Cherenkov Observatory (HAWC), located in the state of Puebla, Mexico, is a wide field instrument (~2 sr) …
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The radio to x-ray spectral shape and variability of blazars
… of a sample of BL Lac objects and OVV quasars ("blazars"). These results have important implications for the unification of BL Lac objects, OVV quasars and low polarisation quasars into a single class of objects showing a smoothly continuous distribution of properties. The spectral shape of the …
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Differential effects of epidermal growth factor receptor inhibitors on glioblastoma multiforme
OBJECTIVE: Glioblastoma Multiforme (GBM), one of the most malignant forms of primary brain tumors, is characterized by its highly heterogenous genetic composition, aggressive infiltration of surrounding tissue, and resistance to current treatments. Gene expression analysis has characterized GBM …
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Observations of variability of TeV gamma-ray blazars
The boom in ground-based gamma-ray astronomy since the beginning of the 21st century has enabled a new probe of the universe using very-high-energy photons. The Very Energetic Radiation Imaging Telescope Array System (VERITAS) is an array of four 12-m imaging Cherenkov telescopes that is sensitive …
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Understanding the Nature of Blazars High Energy Emission with Time Dependent Multi-zone Modeling
… to study the multiwavelength emission of blazars. The multiwavelength variability of blazars is widely believed to be a direct manifestation of the formation and propagation of relativistic jets, and hence the related physics of the black hole - accretion disk - jet system. However, the …