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We present simultaneous Planck, Swift, Fermi, and ground-based data for 105 blazars belonging to three samples with flux limits in the soft X-ray, hard X-ray, and gamma-ray bands. Our unique data set has allowed us to demonstrate that the…

The radio properties of blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed contemporaneously by the Very Long Baseline Array (VLBA). In total, 232 sources were observed with…

Fermi-LAT LCR provide continuous and regularly-sampled gamma-ray light curves, spanning about 14 years, for a large sample of blazars. The log-normal flux distribution and linear RMS-Flux relation of the light curves for a few of Fermi…

高能天体物理现象 · 物理学 2023-07-21 Na Wang , Ting-Feng Yi , Liang Wang , Li-Sheng Mao , Zhi-Yuan Pu , Gong-Ming Ning , Wei-Tian Huang , He Lu , Shun Zhang , Yu-Tong Chen , Liang Dong

Machine learning has emerged as a powerful tool in the field of gamma-ray astrophysics. The algorithms can distinguish between different source types, such as blazars and pulsars, and help uncover new insights into the high-energy universe.…

高能天体物理现象 · 物理学 2024-01-05 Gopal Bhatta , Sarvesh Gharat , Abhimanyu Borthakur , Aman Kumar

The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The Second LAT AGN Catalog (2LAC) includes 1017 gamma-ray sources located at high…

高能天体物理现象 · 物理学 2015-05-30 LAT Collaboration

The LAT instrument, onboard the Fermi satellite, in its first three months of operation detected more than 100 blazars at more than the 10 sigma level. This is already a great improvement with respect to its predecessor, the instrument…

宇宙学与河外天体物理 · 物理学 2009-12-18 G. Ghisellini

We present long term optical and near infrared flux variability analysis of 37 blazars detected in the $\gamma$-ray band by the {\it Fermi Gamma-Ray Space Telescope}. Among them, 30 are flat spectrum radio quasars (FSRQs) and 7 are BL Lac…

高能天体物理现象 · 物理学 2020-08-28 P. Z. Safna , C. S. Stalin , Suvendu Rakshit , Blesson Mathew

In the recently published 3FGL catalogue, the Fermi/LAT collaboration reports the detection of $\gamma$-ray emission from 3034 sources obtained after four years of observations. The nature of 1010 of those sources is unknown, whereas 2023…

高能天体物理现象 · 物理学 2017-06-21 J. Lefaucheur , S. Pita

We revisit the blazar sequence exploiting the complete, flux limited sample of blazars with known redshift detected by the Fermi satellite after 4 years of operations (the 3LAC sample). We divide the sources into gamma-ray luminosity bins,…

高能天体物理现象 · 物理学 2017-05-31 G. Ghisellini , C. Righi , L. Costamante , F. Tavecchio

In this study, we analyze the $\sim 16$ yr Fermi-LAT data of 160 blazars consisting of 92 flat-spectrum radio quasars (FSRQs), 64 BL Lacertae type objects (BL Lacs), and 4 blazar candidates of unknown type objects (BCU), and exhibit their…

高能天体物理现象 · 物理学 2025-01-22 Junhao Deng , Yunguo Jiang

We study the relation between the mass accretion rate, the jet power, and the black hole mass of blazars. To this aim, we make use of the Sloan Digital Sky Survey (SDSS) and the 11 months catalog of blazars detected at energies larger than…

高能天体物理现象 · 物理学 2012-05-18 T. Sbarrato , G. Ghisellini , L. Maraschi , M. Colpi

The Large Area Telescope (LAT) aboard the Fermi Gamma-ray Space Telescope provides an unprecedented opportunity to study gamma-ray blazars. To capitalize on this opportunity, beginning in late 2007, about a year before the start of LAT…

During a decade of the $Fermi$-Large Area Telescope (LAT) operation, thousands of blazars have been detected in the $\gamma$-ray band. However, there are still numbers of blazars that have not been detected in the $\gamma$-ray band. In this…

高能天体物理现象 · 物理学 2021-08-18 Xue-Jiao Deng , Rui Xue , Ze-Rui Wang , Shao-Qiang Xi , Hu-Bing Xiao , Lei-Ming Du , Zhao-Hua Xie

Our knowledge of the blazar surface densities and luminosity functions, which are fundamental parameters, relies still on samples at relatively high flux limits. As a result, our understanding of this rare class of active galactic nuclei is…

天体物理学 · 物理学 2011-02-11 P. Padovani , P. Giommi , H. Landt , E. S. Perlman

Many blazars detected by the Fermi satellite, observed spectroscopically in the optical, are line-less, and have been classified as BL Lac objects. Optical-UV photometry of nearly one hundred of them allowed to determine the redshift for a…

宇宙学与河外天体物理 · 物理学 2015-06-05 G. Ghisellini , F. Tavecchio , L. Foschini , T. Sbarrato , G. Ghirlanda , L. Maraschi

Context. Blazars are a distinct subclass of active galactic nuclei (AGN), known for their fast variability, high polarization, and intense emission across the electromagnetic spectrum, from radio waves to gamma rays. Gamma-ray blazar…

高能天体物理现象 · 物理学 2025-01-08 N. Álvarez Crespo , A. Domínguez , V. S. Paliya , M. Chamorro Cazorla , P. Sánchez Blázquez , A. Gil de Paz

We present deep radio images at 1.4 GHz of a large and complete sample of BL Lacertae objects (BL Lacs) selected from the Deep X-ray Radio Blazar Survey (DXRBS). We have observed 24 northern sources with the Very Large Array (VLA) in both…

天体物理学 · 物理学 2009-11-13 Hermine Landt , Hayley E. Bignall

We used the data from the Fermi Gamma-ray Space Telescope to characterise the {\gamma}-ray flux variability of blazars on month-like time scales. Our sample consists of 1120 blazars of which 481 are flat spectrum radio quasars (FSRQs) and…

高能天体物理现象 · 物理学 2020-02-12 Bhoomika Rajput , C. S. Stalin , Suvendu Rakshit

We utilize machine learning methods to distinguish BL Lacertae objects (BL Lac) from Flat Spectrum Radio Quasars (FSRQ) within a sample of likely X-ray blazar counterparts to Fermi 3FGL unassociated gamma-ray sources. From our previous…

高能天体物理现象 · 物理学 2021-03-03 Amanpreet Kaur , Abraham D. Falcone , Michael C. Stroh

BL Lac objects are an extreme type of active galactic nuclei (AGNs) that belong to the largest population of $\gamma$-ray sources: blazars. This class of AGNs shows a double-bumped spectral energy distribution that is commonly described in…

高能天体物理现象 · 物理学 2020-04-08 E. J. Marchesini , A. Paggi , F. Massaro , N. Masetti , R. D'Abrusco , I. Andruchow , R. de Menezes