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The Second Fermi LAT source catalog (Nolan et al. 2012) includes as many as 1,873 sources, but initial attempts to identify counterparts at other wavelengths resulted in 575 sources remaining unidentified. The 2FGL catalog is based on the…

高能天体物理现象 · 物理学 2015-06-18 Masaki Nishimichi , Takeshi Okuda , Masaki Mori , Philip G. Edwards , Jamie Stevens

In this paper we discuss an application of machine learning based methods to the identification of candidate AGN from optical survey data and to the automatic classification of AGNs in broad classes. We applied four different machine…

宇宙学与河外天体物理 · 物理学 2013-10-14 Stefano Cavuoti , Massimo Brescia , Raffaele D'Abrusco , Giuseppe Longo , Maurizio Paolillo

A significant fraction (~30%) of the high-energy gamma-ray sources listed in the second Fermi LAT catalog (2FGL) are still of unknown origin, being not yet associated with counterparts at low energies. We recently developed a new…

高能天体物理现象 · 物理学 2015-06-15 F. Massaro , R. D'Abrusco , A. Paggi , N. Masetti , M. Giroletti , G. Tosti , Howard A. Smith , S. Funk

We present a new and efficient algorithm for finding point sources in the photon event data stream from the Fermi Gamma-Ray Space Telescope, FermiFAST. The key advantage of FermiFAST is that it constructs a catalogue of potential sources…

天体物理仪器与方法 · 物理学 2017-01-25 Asha Asvathaman , Conor Omand , Alistair Barton , Jeremy S. Heyl

The latest source catalog of the Fermi-LAT telescope contains more than 7000 $\gamma$-ray sources at GeV energies, with the two dominant source classes thought to be blazars and rotation-powered pulsars. Our target is the identification of…

高能天体物理现象 · 物理学 2024-02-09 Martin G. F. Mayer , Werner Becker

The deepest all-sky survey available in the $\gamma$-ray band - the last release of the Fermi-LAT catalogue (4FGL-DR3) based on the data accumulated in 12 years, contains more than 6600 sources. The largest population among the sources is…

高能天体物理现象 · 物理学 2022-12-28 N. Sahakyan , V. Vardanyan , M. Khachatryan

Excess of gamma rays with a spherical morphology around the Galactic center (GC) observed in the Fermi large area telescope (LAT) data is one of the most intriguing features in the gamma-ray sky. The excess has been interpreted by…

高能天体物理现象 · 物理学 2024-06-07 Dmitry V. Malyshev

Building on our previous cross-correlation analysis (Xia et al. 2011) between the isotropic gamma-ray background (IGRB) and different tracers of the large-scale structure of the universe, we update our results using 60-months of data from…

宇宙学与河外天体物理 · 物理学 2015-06-24 Jun-Qing Xia , Alessandro Cuoco , Enzo Branchini , Matteo Viel

We report our detailed data analysis for 39 $\gamma$-ray sources selected from the 992 unassociated sources in the \textit{Fermi} Large Area Telescope (LAT) third source catalog. The selection criteria, which were set for finding candidate…

高能天体物理现象 · 物理学 2021-06-03 Xuejie Dai , Zhongxiang Wang , V. Jithesh , Yi Xing

The recently published fourth Fermi Large Area Telescope source catalog (4FGL) reports 5065 gamma-ray sources in terms of direct observational gamma-ray properties. Among the sources, the largest population is the Active Galactic Nuclei…

高能天体物理现象 · 物理学 2020-01-08 Shi-Ju Kang , Enze Li , Wujing Ou , Kerui Zhu , Jun-Hui Fan , Qingwen Wu , Yue Yin

The determination of distance is fundamental in astrophysics. Gamma-ray sources are poorly characterized in this sense, as the limited angular resolution and poor photon-count statistics in gamma-ray astronomy makes it difficult to…

高能天体物理现象 · 物理学 2023-04-03 Javier Coronado-Blázquez

We present the results of an all-sky radio survey between 5 and 9 GHz of the fields surrounding all unassociated gamma-ray objects listed in the Fermi Large Area Telescope Second Source Catalog (2FGL). The goal of these observations is to…

高能天体物理现象 · 物理学 2015-03-12 Frank K. Schinzel , Leonid Petrov , Gregory B. Taylor , Elizabeth K. Mahony , Philip G. Edwards , Yuri Y. Kovalev

Detection of point sources in images is a fundamental operation in astrophysics, and is crucial for constraining population models of the underlying point sources or characterizing the background emission. Standard techniques fall short in…

天体物理仪器与方法 · 物理学 2018-02-28 Tansu Daylan , Stephen K. N. Portillo , Douglas P. Finkbeiner

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…

高能天体物理现象 · 物理学 2015-05-27 A. Maselli , G. Cusumano , E. Massaro , A. Segreto , V. La Parola , A. Tramacere , I. Donnarumma

Astrophysical sources are now observed by many different instruments at different wavelengths, from radio to high-energy gamma-rays, with an unprecedented quality. Putting all these data together to form a coherent view, however, is a very…

We cross correlate the Fermi 11 months survey catalogue (1FGL) with the 20 GHz Australia Telescope Compact Array radio survey catalogue (AT20G) composed by 5890 sources at declination <0 deg. Among the 738 Fermi sources distributed in the…

高能天体物理现象 · 物理学 2015-05-18 G. Ghirlanda , G. Ghisellini , F. Tavecchio , L. Foschini

With a decade of gamma-ray data from the Fermi-LAT telescope, we can now hope to answer how well we know the local Universe at gamma-ray frequencies. On the other hand, with gamma-ray data alone it is not possible to directly access the…

宇宙学与河外天体物理 · 物理学 2018-11-27 Simone Ammazzalorso , Nicolao Fornengo , Shunsaku Horiuchi , Marco Regis

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

The study of machine learning (ML) techniques for the autonomous classification of astrophysical sources is of great interest, and we explore its applications in the context of a multifrequency data-frame. We test the use of supervised ML…

高能天体物理现象 · 物理学 2020-10-07 Bruno Arsioli , Pedro Dedin

Spatial extension is an important characteristic for correctly associating gamma-ray-emitting sources with their counterparts at other wavelengths and for obtaining an unbiased model of their spectra. We present a new method for quantifying…