English
Related papers

Related papers: A Stacking Survey of Gamma-ray Pulsars

200 papers

We present a method for the detection and characterization of random changes in the flux from $\gamma$-ray pulsars on sub-hour timescales, much shorter than variations that can be accessed using direct flux measurements. Flux variations are…

High Energy Astrophysical Phenomena · Physics 2025-08-26 Matthew Kerr

We report a 5.4\sigma\ detection of pulsed gamma rays from PSR B1821-24 in the globular cluster M28 using ~44 months of Fermi Large Area Telescope (LAT) data that have been reprocessed with improved instrument calibration constants. We…

Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ~ 10 GeV - 1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Spencer Chang , Lisa Goodenough

In this study, we systematically studied the X-ray to GeV gamma-ray spectra of 61 {\it Fermi} Large Area Telescope (LAT) detected radio galaxies. We found an anticorrelation between peak frequency and peak luminosity in the high-energy…

High Energy Astrophysical Phenomena · Physics 2022-06-15 Yasushi Fukazawa , Hiroto Matake , Taishu Kayanoki , Yoshiyuki Inoue , Justin Finke

Employing Fermi-LAT gamma ray observations, several independent groups have found excess extended gamma ray emission at the Galactic center (GC). Both, annihilating dark matter (DM) or a population of $\sim 10^3$ unresolved millisecond…

High Energy Astrophysical Phenomena · Physics 2013-12-12 Chris Gordon , Oscar Macias

We study a sample of 30 high-redshift blazars ($z>2.5$) by means of spectra and the radiation mechanism with Fermi Large Area Telescope $\gamma$-ray observations spanning 15 years. Three models -- the power law, power law with an…

High Energy Astrophysical Phenomena · Physics 2025-01-27 Fan Wu , Benzhong Dai

In this letter, we introduce a new method of image stacking to directly study the undetected but possible gamma-ray point sources. Applying the method to the Australia Telescope 20 GHz Survey (AT20G) sources which have not been detected by…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Ming Zhou , Jiancheng Wang , Xiaoyan Gao

High-redshift blazars are valuable tools to study the early Universe. So far only a handful of $\gamma$-ray blazars have been found at redshifts above 3. $\gamma$-ray signals are detected in the direction of PMN J2219-2719 ($z=3.63$) and…

High Energy Astrophysical Phenomena · Physics 2020-09-09 Shang Li , Lu-Ming Sun , Neng-Hui Liao , Yi-Zhong Fan

Millisecond pulsars (MSPs) have been established as a class of high-energy ($\geq$0.1 GeV) emitters with the Large Area Telescope (LAT) aboard the \emph{Fermi Gamma-ray Space Telescope}. Most MSP gamma-ray light curves display sharp peaks…

High Energy Astrophysical Phenomena · Physics 2012-09-19 T. J. Johnson

We conduct X-ray spectral fits on 184 likely counterparts to Fermi-LAT 3FGL unassociated sources. Characterization and classification of these sources allows for more complete population studies of the high-energy sky. Most of these X-ray…

High Energy Astrophysical Phenomena · Physics 2021-03-02 Stephen Kerby , Amanpreet Kaur , Abraham D. Falcone , Michael C. Stroh , Elizabeth C. Ferrara , Jamie A. Kennea , Joseph Colosimo

The pulsar glitches are generally assumed to be an apparent manifestation of the superfluid interior of the neutron stars. Most of them were discovered and extensively studied by continuous monitoring in the radio wavelengths. The Fermi-LAT…

Instrumentation and Methods for Astrophysics · Physics 2022-04-20 E. V. Sokolova , A. G. Panin

High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The six or more pulsars seen by CGRO/EGRET show that: the light curves usually have double-peak…

Astrophysics · Physics 2009-11-06 David J. Thompson

We present results of Compton Gamma-Ray Observatory EGRET observations of the unidentified high-energy gamma-ray sources 2EG J1049-5847 (GEV J1047-5840, 3EG J1048-5840) and 2EG J1103-6106 (3EG J1102-6103). These sources are spatially…

Astrophysics · Physics 2009-10-31 V. M. Kaspi , J. R. Lackey , J. Mattox , R. N. Manchester , M. Bailes , R. Pace

We address four unique signatures in pulsar gamma-ray radiation as predicted by polar-cap models. These signatures are expected to be present nearby the spectral high-energy cutoff at around several GeV. Their magnitude and, therefore,…

Astrophysics · Physics 2009-11-07 J. Dyks , B. Rudak

The Fermi Large Area Telescope (LAT) has revealed a mysterious extended excess of GeV gamma-ray emission around the Galactic Center, which can potentially be explained by unresolved emission from a population of pulsars, particularly…

The Fermi Large Area Telescope (LAT) has revolutionized high-energy (HE) astronomy, and is making enormous contributions particularly to gamma-ray pulsar science. As a result of the many new pulsar discoveries, the gamma-ray pulsar…

High Energy Astrophysical Phenomena · Physics 2011-12-15 C. Venter , T. J. Johnson , A. K. Harding

The Fermi All-sky Variability Analysis (FAVA) provides a photometric alternative for identifying week-long gamma-ray flares across the entire sky while being independent of any diffuse Galactic or isotropic emission model. We reviewed 779…

High Energy Astrophysical Phenomena · Physics 2024-02-29 Scott D. Joffre , Núria Torres-Albà , Marco Ajello , Daniel Kocevski , Rolf Buehler

We report the discovery of four gamma-ray pulsars, detected in computing-intensive blind searches of data from the Fermi Large Area Telescope (LAT). The pulsars were found using a novel search approach, combining volunteer distributed…

We report an evidence for the first time that merging clusters of galaxies are a promising candidate for the origin of high galactic-latitude, steady unidentified EGRET gamma-ray sources. Instead of using past optical catalogs of…

Astrophysics · Physics 2008-11-26 Wataru Kawasaki , Tomonori Totani

Approximately one-third of the gamma-ray sources in the third Fermi-LAT catalog are unidentified or unassociated with objects at other wavelengths. Observations with Swift-XRT have yielded possible counterparts in $\sim$30% of these source…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Amanpreet Kaur , Abraham D Falcone , Michael D Stroh , Jamie A Kennea , Elizabeth C Ferrara
‹ Prev 1 8 9 10 Next ›