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Pulsed gamma rays have been detected with the Fermi Large Area Telescope (LAT) from more than 20 millisecond pulsars (MSPs), some of which were discovered in radio observations of bright, unassociated LAT sources. We have fit the radio and…

High Energy Astrophysical Phenomena · Physics 2011-11-04 Tyrel J. Johnson , Alice K. Harding , Christo Venter

We present a stacking method that makes use of co-added maps of gamma-ray counts produced from data taken with the Fermi Large Area Telescope. Sources with low integrated gamma-ray fluxes that are not detected individually may become…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 B. Huber , C. Farnier , A. Manalaysay , U. Straumann , R. Walter

During its first four years of scientific observations, the Fermi Large Area Telescope (Fermi-LAT) detected 3033 $\gamma$-ray sources above a 4$\sigma$ significance level. Although most of the extra-Galactic sources are active galactic…

High Energy Astrophysical Phenomena · Physics 2019-08-15 G. La Mura , G. Chiaro , S. Ciroi , P. Rafanelli , D. Salvetti , M. Berton , V. Cracco

Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good…

High Energy Astrophysical Phenomena · Physics 2017-06-01 Thomas Armstrong , Anthony M. Brown , Paula M. Chadwick

We report on the analysis of 13 gamma-ray pulsars discovered in the Einstein@Home blind search survey using Fermi Large Area Telescope (LAT) Pass 8 data. The 13 new gamma-ray pulsars were discovered by searching 118 unassociated LAT sources…

Classifying catalog objects as stars, galaxies, or AGN is a crucial part of any statistical study of galaxies. We describe our pipeline for binary (star/galaxy) and multiclass (star/galaxy/Type I AGN/Type II AGN) classification developed…

Astrophysics of Galaxies · Physics 2021-04-14 Anneya Golob , Marcin Sawicki , Andy D. Goulding , Jean Coupon

We search for the presence of double gamma-ray line from unassociated Fermi-LAT sources including detailed Monte Carlo simulations to study its global statistical significance. Applying the Su & Finkbeiner selection criteria for high-energy…

High Energy Astrophysical Phenomena · Physics 2012-08-10 Andi Hektor , Martti Raidal , Elmo Tempel

Context. Serendipitous X-ray surveys have proven to be an efficient way to find rare objects, for example tidal disruption events, changing-look active galactic nuclei (AGN), binary quasars, ultraluminous X-ray sources (ULXs), and…

High Energy Astrophysical Phenomena · Physics 2022-01-26 Hugo Tranin , Olivier Godet , Natalie Webb , Daria Primorac

The Fermi Large Area Telescope (LAT) provides advantages for radio pulsar searches by enabling efficient target selection. We can confidently point radio telescopes to the positions of Fermi unidentified gamma-ray sources that have a high…

Identifying stars belonging to different classes is vital in order to build up statistical samples of different phases and pathways of stellar evolution. In the era of surveys covering billions of stars, an automated method of identifying…

Instrumentation and Methods for Astrophysics · Physics 2024-10-31 Sean Enis Cody , Sebastian Scher , Iain McDonald , Albert Zijlstra , Emma Alexander , Nick L. J. Cox

Radio-loud sources with blazar-like properties, but having a jet that does not directly point in the direction of the observer are among the most interesting classes of gamma-ray emitters. These sources are known as Misaligned Active…

Astrophysics of Galaxies · Physics 2020-07-30 G. Chiaro , G. La Mura , A. Dominguez , S. Bisogni

In the era of large photometric surveys, the importance of automated and accurate classification is rapidly increasing. Specifically, the separation of resolved and unresolved sources in astronomical imaging is a critical initial step for a…

Instrumentation and Methods for Astrophysics · Physics 2019-02-07 Yutaro Tachibana , A. A. Miller

New-generation radio telescopes like LOFAR are conducting extensive sky surveys, detecting millions of sources. To maximise the scientific value of these surveys, radio source components must be properly associated into physical sources…

This study introduces the Misclassification Likelihood Matrix (MLM) as a novel tool for quantifying the reliability of neural network predictions under distribution shifts. The MLM is obtained by leveraging softmax outputs and clustering…

We present the results of our follow-up observation program of gamma-ray sources detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. 26 blazars and 39 sources unidentified at other wavelengths were…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Mai Fujiwara , Yoshiki Matsuoka , Nobuyuki Ienaka

We used 3.1 million spectroscopically labelled sources from the Sloan Digital Sky Survey (SDSS) to train an optimised random forest classifier using photometry from the SDSS and the Widefield Infrared Survey Explorer (WISE). We applied this…

Astrophysics of Galaxies · Physics 2020-07-15 A. O. Clarke , A. M. M. Scaife , R. Greenhalgh , V. Griguta

A significant fraction ($\sim 30$ %) of the high-energy gamma-ray sources listed in the second $\textit{Fermi}$ LAT (2FGL) catalog are still of unknown origin, being not yet associated with counterparts at lower energies. In order to…

High Energy Astrophysical Phenomena · Physics 2015-06-19 A. Paggi , F. Massaro , R. D'Abrusco , H. A. Smith , N. Masetti , M. Giroletti , G. Tosti , S. Funk

Fermi-LAT unidentified sources (unIDs) have proven to be compelling targets for performing indirect dark matter (DM) searches. In a previous work, we found that among the 1235 unIDs in Fermi-LAT catalogs (3FGL, 2FHL and 3FHL) only 44 of…

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…

High Energy Astrophysical Phenomena · Physics 2015-05-30 LAT Collaboration

We searched for radio pulsars in 25 of the non-variable, unassociated sources in the Fermi LAT Bright Source List with the Green Bank Telescope at 820 MHz. We report the discovery of three radio and gamma-ray millisecond pulsars (MSPs) from…