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Related papers: Multiwavelength Study of High-Redshift Blazars

200 papers

We investigate the $\gamma$-ray and X-ray properties of the flat spectrum radio quasar (FSRQ) \4c50 at redshift $z= 1.517$. The {\it Fermi} Large Area Telescope (LAT) data indicate that this source was in an active state since 2013 July.…

High Energy Astrophysical Phenomena · Physics 2021-06-03 Jianeng Zhou , V. Jithesh , Chen Liang , Zhongxiang Wang

Context. Blazars are among the most energetic objects in the Universe. In 2008 August, Fermi/LAT detected the blazar PKS 1502+106 showing a rapid and strong gamma-ray outburst followed by high and variable flux over the next months. This…

High Energy Astrophysical Phenomena · Physics 2016-01-27 V. Karamanavis , L. Fuhrmann , T. P. Krichbaum , E. Angelakis , J. Hodgson , I. Nestoras , I. Myserlis , J. A. Zensus , A. Sievers , S. Ciprini

The uncharted territory of the high-redshift ($z\gtrsim3$) Universe holds the key to understand the evolution of quasars. In an attempt to identify the most extreme members of the quasar population, i.e., blazars, we have carried out a…

High Energy Astrophysical Phenomena · Physics 2020-07-22 Vaidehi S. Paliya , M. Ajello , H. -M. Cao , M. Giroletti , Amanpreet Kaur , Greg Madejski , Benoit Lott , D. Hartmann

Blazars are the brightest and most abundant persistent sources in the extragalactic gamma-ray sky. Due to their significance, they are often observed across various energy bands to explore potential correlations between emissions at…

High Energy Astrophysical Phenomena · Physics 2024-01-22 P. Giommi , N. Sahakyan , D. Israyelyan , M. Manvelyan

We present the results of our analysis devoted to the research of sources emitting in the energy bands surveyed by both the Swift-BAT and the Fermi-LAT telescopes. We cross-correlate the Fermi-LAT 1-year point source catalogue (1FGL) of…

High Energy Astrophysical Phenomena · Physics 2015-05-27 A. Maselli , G. Cusumano , E. Massaro , A. Segreto , V. La Parola , A. Tramacere , I. Donnarumma

We investigate the spectral properties of the brightest gamma-ray flares of blazars detected by the Fermi Large Area Telescope. We search for the presence of spectral breaks and measure the spectral curvature on typical time scales of a few…

High Energy Astrophysical Phenomena · Physics 2015-06-24 Susanna Kohler , Krzysztof Nalewajko

Blazars are the most violent steady/recurrent sources of high-energy gamma-ray emission in the known Universe. They are prominent emitters of electromagnetic radiation throughout the entire electromagnetic spectrum. The observable radiation…

Astrophysics · Physics 2008-11-26 Markus Boettcher

Blazars are highly variable, radio-loud active galactic nuclei with jets oriented at a small angle to the line of sight. The observed emission of these sources covers the whole electromagnetic spectrum from radio frequencies up to the high…

High Energy Astrophysical Phenomena · Physics 2016-04-20 Alicja Wierzcholska

Blazars are a subclass of active galactic nuclei (AGN) that emit non-thermal radiation through relativistic jets, characterized by rapid flux and polarization variability. High synchrotron-peaked blazars (HSPs) and extreme high…

High Energy Astrophysical Phenomena · Physics 2025-11-26 Adithiya Dinesh , Alberto Dominguez , V. Paliya , J. L. Contreras , S. Buson , M. Ajello

The highest-energy blazars exhibit non-thermal radiation extending beyond 1 TeV with high luminosities and strong variabilities, indicating extreme particle acceleration in their relativistic jets. The gamma-ray spectra of blazars contain…

High Energy Astrophysical Phenomena · Physics 2022-09-21 Qi Feng

The most powerful sources among the blazar family are MeV blazars. Often detected at $z>2$, they usually display high X- and \gm-ray luminosities, larger-than-average jet powers and black hole masses $\gtrsim 10^9 M_{\odot}$. In the present…

High Energy Astrophysical Phenomena · Physics 2017-04-26 L. Marcotulli , V. S. Paliya , M. Ajello , A. Kaur , D. H. Hartmann , D. Gasparrini , J. Greiner , A. Rau , P. Schady , M. Balokovic , D. Stern , G. Madejski

We carried a detailed spectral and temporal study of blazar, \mbox{PKS\,0903-57} using the \emph{Fermi}-LAT and \emph{Swift}-XRT/UVOT observations, during its brightest flaring period MJD\,58931--58970. During this period, the maximum daily…

High Energy Astrophysical Phenomena · Physics 2021-06-03 Zahir Shah , V. Jithesh , S. Sahayanathan , Naseer Iqbal

Blazars are jet-dominated extragalactic objects characterized by the emission of strongly variable non-thermal radiation across the entire electromagnetic spectrum. Therefore, the study of blazars (and in general of radio loud AGN) through…

High Energy Astrophysical Phenomena · Physics 2019-08-15 C. Monte , S. Raino , F. Gargano , S. Cutini , D. Gasparrini , J. Leon Tavares , G. Polenta

Using public \fermi LAT and \swift BAT observations, we constructed the first sample of blazars selected at both hard X-rays and gamma-rays. Studying its spectral properties, we find a luminosity dependence of the spectral slopes at both…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-22 R. M. Sambruna , D. Donato , M. Ajello , L. Maraschi , the GSFC BAT Team

Blazars exhibit flux and spectral variations of largest amplitude at the highest frequencies. Therefore, monitoring their variability at X- and gamma-rays is the most effective tool to peer into the mighty powerhouse of these sources. High…

Astrophysics · Physics 2007-05-23 Elena Pian

We have presented a multiwavelength temporal and spectral study of the Blazar PKS 0346-27 for the period 2019 January-2021 December (MJD 58484-59575) using data from Fermi-LAT (gamma-rays), Swift-XRT (X-rays) and Swift-UVOT (ultra-violet…

High Energy Astrophysical Phenomena · Physics 2023-01-25 Sushanth Reddy Kamaram , Raj Prince , Suman Pramanick , Debanjan Bose

Violent multi-wavelength variabilities are observed in gamma-ray-selected blazars. We present an analysis of long-term light curves for eight bright blazars to explore the co-variation pattern in the gamma-ray and radio bands. We extract…

High Energy Astrophysical Phenomena · Physics 2020-05-27 Hai-Ming Zhang , Zhen-Jie Wang , Jin Zhang , Ting-Feng Yi , Liang Chen , Rui-Jing Lu , En-Wei Liang

We present an in-depth and systematic variability study of a sample of 20 powerful blazars, including 12 BL Lacs and 8 flat spectrum radio quasars, applying various analysis tools such as flux distribution, symmetry analysis, and time…

High Energy Astrophysical Phenomena · Physics 2020-03-18 Gopal Bhatta , Niraj Dhital

We search through $\gamma$-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope and find 24 blazars (or candidates) that have a single clear flare event in their 9.5 year long-term light curves.…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Gege Wang , Zhongxiang Wang , Liang Chen , Jianeng Zhou , Yi Xing

Blazars are a small fraction of all extragalactic sources but, unlike other objects, they are strong emitters across the entire electromagnetic spectrum. In this study we have conducted a detailed investigation of the broad-band spectral…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 S. Cutini , D. Gasparrini , P. Giommi , M. N. Mazziotta , C. Monte