Results 51 to 60 of about 20,672 (255)

Multiwavelength Variability Analysis of 3C 279

Frontiers in Astronomy and Space Sciences, 2017
We present a multifrequency analysis of the variability in the flat-spectrum radio quasar 3C 279 from 2008 to 2014. Our multiwavelength datasets range from 1 mm to gamma-rays, with additional optical polarimetry.
Víctor M. Patiño-Álvarez, Sunil Fernandes, Vahram Chavushyan, Erique López-Rodríguez, Jonathan León-Tavares, Eric M. Schlegel, Luis Carrasco, José R. Valdés, Alberto Carramiñana   +8 more
doaj   +1 more source

A Decade of Multiwavelength Observations of the TeV Blazar 1ES 1215+303: Extreme Shift of the Synchrotron Peak Frequency and Long-term Optical–Gamma-Ray Flux Increase [PDF]

Astrophysical Journal, 2020
Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares.
J. Valverde, D. Horan, D. Bernard, S. Fegan, A. Abeysekara, A. Archer, W. Benbow, R. Bird, A. Brill, R. Brose, M. Buchovecky, J. Buckley, J. Christiansen, W. Cui, W. Cui, A. Falcone, Q. Feng, J. Finley, L. Fortson, A. Furniss, A. Gent, G. Gillanders, C. Giuri, O. Gueta, D. Hanna, T. Hassan, O. Hervet, J. Holder, G. Hughes, T. Humensky, P. Kaaret, N. Kelley-Hoskins, M. Kertzman, D. Kieda, M. Krause, F. Krennrich, M. Lang, G. Maier, P. Moriarty, R. Mukherjee, D. Nieto, M. Nievas-Rosillo, S. O’Brien, R. Ong, A. Otte, N. Park, A. Petrashyk, K. Pfrang, A. Pichel, M. Pohl, R. Prado, E. Pueschel, J. Quinn, K. Ragan, P. Reynolds, D. Ribeiro, G. Richards, E. Roache, I. Sadeh, M. Santander, S. Scott, G. Sembroski, K. Shahinyan, R. Shang, I. Sushch, V. Vassiliev, A. Weinstein, R. Wells, P. Wilcox, A. Wilhelm, D. Williams, T. Williamson, Giuliana Noto, P. Edwards, B. Piner, B. Piner, V. Ramazani, T. Hovatta, T. Hovatta, J. Jormanainen, E. Lindfors, K. Nilsson, L. Takalo, Y. Kovalev, Y. Kovalev, M. Lister, A. Pushkarev, T. Savolainen, T. Savolainen, S. Kiehlmann, S. Kiehlmann, S. Kiehlmann, W. Max-Moerbeck, A. Readhead, A. Lähteenmäki, M. Tornikoski   +95 more
semanticscholar   +1 more source

Optical and Gamma-Ray Variability of the vRL NLSy1 Galaxy, 1H 0323+342

Galaxies, 2017
1H 0323+342 was one of the first vRLNLSy1 galaxies detected at gamma-rays with the Fermi-LAT and is one of the brightest of this class observed at optical wavelengths.
Hugh R. Miller, Clay. S. Turner, Jeremy D. Maune, Joseph R. Eggen   +3 more
doaj   +1 more source

Flare Duty Cycle of Gamma-Ray Blazars and Implications for High-energy Neutrino Emission

The Astrophysical Journal, 2023
Gamma-ray flares of blazars may be accompanied by high-energy neutrinos due to interactions of high-energy cosmic rays in the jet with photons, as suggested by the detection of the high-energy neutrino IceCube-170922A during a major gamma-ray flare from ...
Kenji Yoshida, Maria Petropoulou, Kohta Murase, Foteini Oikonomou   +3 more
doaj   +1 more source

Dissecting the region around IceCube-170922A: the blazar TXS 0506+056 as the first cosmic neutrino source [PDF]

Monthly notices of the Royal Astronomical Society, 2018
We present the dissection in space, time, and energy of the region around the IceCube-170922A neutrino alert. This study is motivated by: (1) the first association between a neutrino alert and a blazar in a flaring state, TXS 0506+056; (2) the evidence ...
P. Padovani, P. Giommi, P. Giommi, E. Resconi, T. Glauch, B. Arsioli, N. Sahakyan, M. Huber   +7 more
semanticscholar   +1 more source

The relativistic jet dichotomy and the end of the blazar sequence [PDF]

, 2020
Our understanding of the unification of jetted AGN has evolved greatly as jet samples have increased in size (e.g. 132 sources for the blazar sequence of Fossati et al., (1998), 257 for the blazar envelope of Meyer et al., (2011)).
M. Keenan, E. Meyer, M. Georganopoulos, Karthik Reddy, Omar French   +4 more
semanticscholar   +1 more source

Looking at Blazar Light-curve Periodicities with Gaussian Processes [PDF]

Astrophysical Journal, 2020
Temporal analysis of blazar flux is a powerful tool to draw inferences about the emission processes and physics of these sources. In the most general case, the available light curves are irregularly sampled and influenced by gaps, and in addition are ...
S. Covino, M. Landoni, A. Sandrinelli, A. Treves   +3 more
semanticscholar   +1 more source

Accretion discs in blazars [PDF]

Monthly Notices of the Royal Astronomical Society, 2009
Accepted for publication (17 August 2009) in ...
Jolley, E. J. D., Kuncic, Zdenka, Bicknell, Geoffrey, Wagner, Stefan J   +3 more
openaire   +3 more sources

Jet Physics of Accreting Super-Massive Black Holes in the Era of the Fermi Gamma-ray Space Telescope

Frontiers in Astronomy and Space Sciences, 2017
The Fermi Gamma-ray Space Telescope with its main instrument on-board, the Large Area Telescope (LAT), opened a new era in the study of high-energy emission from Active Galactic Nuclei (AGN).
Filippo D'Ammando, Filippo D'Ammando
doaj   +1 more source

A Two-zone Blazar Radiation Model for “Orphan” Neutrino Flares [PDF]

, 2020
In this work, we investigate the 2014–2015 neutrino flare associated with the blazar TXS 0506+056 and a recently discovered muon neutrino event IceCube-200107A in spatial coincidence with the blazar 4FGL J0955.1+3551, under the framework of a two-zone ...
R. Xue, Ruo-Yu Liu, Ze-Rui Wang, N. Ding, Xiang-Yu Wang   +4 more
semanticscholar   +1 more source