J. D. Magill
A5083308427- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Particle Detector Development and Performance
- Scientific Research and Discoveries
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Solar and Space Plasma Dynamics
- Particle Accelerators and Free-Electron Lasers
- Particle physics theoretical and experimental studies
- Stellar, planetary, and galactic studies
- Particle accelerators and beam dynamics
- Atomic and Subatomic Physics Research
- Cosmology and Gravitation Theories
- Neutrino Physics Research
- Space Science and Extraterrestrial Life
University of Maryland, College Park
2016-2018
Max Planck Society
2018
Kavli Institute for Particle Astrophysics and Cosmology
2017
SLAC National Accelerator Laboratory
2017
The Fermi Large Area Telescope (LAT) has provided the most detailed view to date of emission towards Galactic centre (GC) in high-energy gamma-rays. This paper describes analysis data taken during first 62 months mission energy range 1-100 GeV from a $15^\circ \times 15^\circ$ region about direction GC, and implications for interstellar emissions produced by cosmic ray (CR) particles interacting with gas radiation fields inner Galaxy point sources detected. Specialised models (IEMs) are...
Abstract The region around the Galactic Center (GC) is now well established to be brighter at energies of a few GeV than what expected from conventional models diffuse gamma-ray emission and catalogs known sources. We study excess using 6.5 yr data Fermi Large Area Telescope. characterize uncertainty GC spectrum morphology due uncertainties in cosmic-ray source distributions propagation, distribution interstellar gas Milky Way, potential contribution bubbles. also evaluate properties...
We present a catalog of sources detected above 10 GeV by the Fermi Large Area Telescope (LAT) in first 7 years data using Pass 8 event-level analysis. This is Third Catalog Hard Fermi-LAT Sources (3FHL), containing 1556 objects characterized - 2 TeV energy range. The sensitivity and angular resolution are improved factors 3 relative to previous LAT at same energies (1FHL). vast majority (79%) associated with extragalactic counterparts other wavelengths, including 16 located very high...
On 2015 June 16, Fermi-LAT observed a giant outburst from the flat spectrum radio quasar 3C 279 with peak $>100$ MeV flux of $\sim3.6\times10^{-5}\;{\rm photons}\;{\rm cm}^{-2}\;{\rm s}^{-1}$ averaged over orbital period intervals. It is historically highest $\gamma$-ray source including past EGRET observations, isotropic luminosity reaching $\sim10^{49}\;{\rm erg}\;{\rm s}^{-1}$. During outburst, Fermi spacecraft, which has an 95.4 min, was operated in special pointing mode to optimize...
Fermipy is an open-source python framework that facilitates analysis of data collected by the Fermi Large Area Telescope (LAT). built on Science Tools, publicly available software suite provided NASA for LAT mission. provides a high-level interface analyzing in simple and reproducible way. The current feature set includes methods extracting spectral energy distributions lightcurves, generating test statistic maps, finding new source candidates, fitting position extension. leverages...
Abstract We present a search for spatial extension in high-latitude ( ) sources recent Fermi point source catalogs. The result is the High-Latitude Extended Sources Catalog, which provides extensions (or upper limits thereof) and likelihood profiles suite of tested morphologies. find 24 extended sources, 19 were not previously characterized as extended. These include that are potentially associated with supernova remnants star-forming regions. also found γ -ray emission vicinity Cen A radio...
The Fermi Large Area Telescope (LAT) Collaboration has recently released a catalog of 360 sources detected above 50 GeV (2FHL). This was obtained using 80 months data re-processed with Pass 8, the newest event-level analysis, which significantly improves acceptance and angular resolution instrument. Most 2FHL at high Galactic latitude are blazars. Using detailed Monte Carlo simulations, we measure, for first time, source count distribution, dN/dS, extragalactic γ-ray E>50 find that it is...
ABSTRACT To uniformly determine the properties of supernova remnants (SNRs) at high energies, we have developed first systematic survey energies from 1 to 100 GeV using data Fermi Large Area Telescope (LAT). Based on spatial overlap sources detected with SNRs known radio surveys, classify 30 as likely SNRs. We also report 14 marginal associations and 245 flux upper limits. A mock catalog in which positions are scrambled Galactic longitude allows us an limit 22% number candidates falsely...
Gamma rays reveal the Universe's history How many stars have formed in Universe, and when did they do so? These fundamental questions are difficult to answer because there systematic uncertainties converting light we observe into total mass of galaxies. The Fermi-LAT Collaboration addressed these by exploiting way that gamma from distant blazars propagate through intergalactic space, which depends on amount emitted all collaboration found star formation peaked about 3 billion years after Big...
ABSTRACT We report the Fermi Large Area Telescope detection of extended γ -ray emission from lobes radio galaxy Fornax A using 6.1 years Pass 8 data. After Centaurus A, this is now second example an source attributed to a galaxy. Both flat disk morphology and following were preferred over point-source description, core contribution was constrained be <?CDATA $\lt 14$?> % total flux. alignment elongation with demonstrated by rotating template. found no significant evidence for variability on...
The detection of high-redshift ($z>$3) blazars enables the study evolution most luminous relativistic jets over cosmic time. More importantly, tend to host massive black holes and can be used constrain space density heavy in early Universe. Here, we report first with \fermi-Large Area Telescope five \gm-ray emitting beyond $z=3.1$, more distant than any previously detected $\gamma$-rays. Among these objects, NVSS J151002+570243 is now known blazar at $z=4.31$. These objects have steeply...
Abstract We report on the Fermi -LAT detection of high-energy emission from behind-the-limb (BTL) solar flares that occurred 2013 October 11, and 2014 January 6 September 1. The observations are associated with active regions originating behind both eastern western limbs, as determined by STEREO . All three very fast coronal mass ejections (CMEs) strong energetic particle events. present updated localizations >100 MeV photon emission, hard X-ray (HXR) EUV images, broadband spectra 10 keV...
The Large Area Telescope on board the Fermi Gamma-ray Space has collected largest ever sample of high-energy cosmic-ray electron and positron events since beginning its operation. Potential anisotropies in arrival directions electrons or positrons could be a signature presence nearby sources. We use almost seven years data with energies above 42 GeV processed Pass 8 reconstruction. present can probe dipole down to level 10^{-3}. take into account systematic effects that mimic true at this...
The spatial extension of a gamma-ray source is an essential ingredient to determine its spectral properties as well potential multi-wavelength counterpart. capability spatially resolve sources greatly improved by the newly delivered Fermi-Large Area Telescope (LAT) Pass 8 event-level analysis which provides greater acceptance and point spread function, two crucial factors for detection extended sources. Here, we present complete search located within 7 degrees from Galactic plane, using 6...
A citizen science project discovers a new type of gamma-ray millisecond pulsar with no detectable radio pulsations.
Fermipy is an open-source python framework that facilitates analysis of data collected by the Fermi Large Area Telescope (LAT). built on Science Tools, publicly available software suite provided NASA for LAT mission. provides a high-level interface analyzing in simple and reproducible way. The current feature set includes methods extracting spectral energy distributions lightcurves, generating test statistic maps, finding new source candidates, fitting position extension. leverages...
We present the second catalog of flaring gamma-ray sources (2FAV) detected with Fermi All-sky Variability Analysis (FAVA), a tool that blindly searches for transients over entire sky observed by Large Area Telescope (LAT) on board \textit{Fermi} Gamma-ray Space Telescope. With respect to first FAVA catalog, this benefits from larger data set, latest LAT release (Pass 8), as well an improved analysis includes likelihood techniques more precise localization transients. Applying 7.4 years...
Abstract We present the Fermi Large Area Telescope (LAT) observations of binary neutron star merger event GW170817 and associated short gamma-ray burst (SGRB) GRB 170817A detected by Gamma-ray Burst Monitor. The LAT was entering South Atlantic Anomaly at time LIGO/Virgo trigger ( t GW ) therefore cannot place constraints on existence high-energy E > 100 MeV) emission with moment coalescence. focus instead constraining longer timescales. No candidate electromagnetic counterpart timescales...
We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of LIGO binary black hole merger event GW151226 candi- date LVT151012. No candidate electromagnetic counterparts were detected by either GBM or LAT. a detailed analysis LAT data over range timescales from seconds to years, using automated pipelines new techniques for char- acterizing upper limits across large area sky. Due partial coverage localization regions at trigger times both events, dif-...
Black holes with masses below approximately $10^{15}$ g are expected to emit gamma rays energies above a few tens of MeV, which can be detected by the Fermi Large Area Telescope (LAT). Although black these cannot formed as result stellar evolution, they may have in early Universe and therefore called Primordial Holes (PBHs). Previous searches for PBHs focused on either short timescale bursts or contribution isotropic gamma-ray emission. We show that, case individual PBHs, LAT is most...
We have measured the gamma-ray emission spectrum of Moon using data collected by Large Area Telescope onboard Fermi satellite during its first seven years operation, in energy range from 30 MeV up to a few GeV. also studied time evolution flux, finding correlation with solar activity. developed full Monte Carlo simulation describing interactions cosmic rays lunar surface. The results present analysis can be explained framework this model, where production gamma is due cosmic-ray proton and...
The gamma-ray sky has been observed with unprecedented accuracy in the last decade by Fermi -large area telescope (LAT), allowing us to resolve and understand high-energy Universe. nature of remaining unresolved emission [unresolved background (UGRB)] below LAT source detection threshold can be uncovered characterizing amplitude angular scale UGRB fluctuation field. This Letter presents a measurement autocorrelation power spectrum based on eight years Fermi-LAT Pass 8 data products. analysis...
RCW 86 is a young supernova remnant (SNR) showing shell-type structure at several wavelengths and thought to be an efficient cosmic-ray (CR) accelerator. Earlier \textit{Fermi} Large Area Telescope results reported the detection of $\gamma$-ray emission coincident with position but its origin (leptonic or hadronic) remained unclear due poor statistics. Thanks 6.5 years data acquired by \textit{Fermi}-LAT new event reconstruction Pass 8, we report significant spatially extended coming from...
We use joint observations by the Neil Gehrels Swift X-ray Telescope (XRT) and Fermi Large Area (LAT) of gamma-ray burst (GRB) afterglows to investigate nature long-lived high-energy emission observed LAT. Joint broadband spectral modeling XRT LAT data reveal that non-detections bright are consistent with a cooling break in inferred electron synchrotron spectrum below and/or energy ranges. Such is sufficient suppress so as be detection threshold. By contrast, LAT-detected bursts best fit lies...