A5063715324- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Calibration and Measurement Techniques
- Astronomy and Astrophysical Research
- CCD and CMOS Imaging Sensors
- Infrared Target Detection Methodologies
- Galaxies: Formation, Evolution, Phenomena
- Particle Accelerators and Free-Electron Lasers
- Particle physics theoretical and experimental studies
- Superconducting and THz Device Technology
- Stellar, planetary, and galactic studies
- Advanced Semiconductor Detectors and Materials
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Cosmology and Gravitation Theories
- Radio Wave Propagation Studies
- Photocathodes and Microchannel Plates
- Precipitation Measurement and Analysis
- Neutrino Physics Research
Goddard Space Flight Center
2008-2024
University of Maryland, College Park
2023
University of Maryland, Baltimore County
2008-2022
University of Maryland, Baltimore
2021-2022
University of Mary
2016-2018
Institute of Astronomy and Space Physics
2010-2016
University of Buenos Aires
1996-2013
University of Oxford
2008
Deleted Institution
2008
Florida Institute of Technology
2008
(Abridged) The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on Fermi Gamma-ray Space (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering energy range from below 20 MeV to more than 300 GeV. This paper describes LAT, its pre-flight expected performance, and summarizes key science objectives that will be addressed. On-orbit performance presented in detail a subsequent paper. LAT pair-conversion telescope with precision...
ABSTRACT We present a catalog of high-energy gamma-ray sources detected by the Large Area Telescope (LAT), primary science instrument on Fermi Gamma-ray Space (Fermi) , during first 11 months phase mission, which began 2008 August 4. The First -LAT (1FGL) contains 1451 and characterized in 100 MeV to GeV range. Source detection was based average flux over month period, threshold likelihood Test Statistic is 25, corresponding significance just 4σ. 1FGL includes source location regions,...
Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) the sources of galactic cosmic rays, unequivocal evidence for acceleration protons in these objects is still lacking. When encounter interstellar material, they produce neutral pions, which turn decay into gamma rays. This offers a compelling way detect sites protons. The identification pion-decay has been difficult because high-energy electrons also via...
We present the results of our analysis cosmic-ray electrons using about $8\ifmmode\times\else\texttimes\fi{}{10}^{6}$ electron candidates detected in first 12 months on-orbit by Fermi Large Area Telescope. This work extends previously published spectrum down to 7 GeV, giving a spectral range approximately 2.5 decades up 1 TeV. describe detail and its validation beam-test data. In addition, we measured via subset events selected for best energy resolution as cross-check on measurement full...
Recent detections of the starburst galaxies M82 and NGC 253 by gamma-ray telescopes suggest that rapidly forming massive stars are more luminous at energies compared to their quiescent relatives. Building upon those results, we examine a sample 69 dwarf, spiral, ultraluminous infrared photon 0.1–100 GeV using 3 years data collected Large Area Telescope (LAT) on Fermi Gamma-ray Space (Fermi). Measured fluxes from significantly detected sources flux upper limits for remaining used explore...
We present observations of the young supernova remnant (SNR) RX J1713.7−3946 with Fermi Large Area Telescope (LAT). clearly detect a source positionally coincident SNR. The is extended best-fit extension 055 ± 004 matching size non-thermal X-ray and TeV gamma-ray emission from remnant. positional coincidence allow us to identify LAT SNR J1713.7−3946. spectrum can be described by very hard power law photon index Γ = 1.5 0.1 that coincides in normalization steeper H.E.S.S.-detected at higher...
We report observation of the supernova remnant IC443 (G189.1+3.0) with Fermi Gamma-ray Space Telescope Large Area (LAT) in energy band between 200MeV and 50GeV. is a shell-type mixed morphology located off outer Galactic plane where high-energy emission has been detected X-ray, GeV TeV gamma-ray bands. Past observations suggest interacting surrounding interstellar matter. Proximity dense shocked molecular clouds GeV-TeV regions by EGRET, MAGIC VERITAS suggests an interpretation that...
We report on the first detection of GeV high-energy gamma-ray emission from a young supernova remnant with Large Area Telescope aboard Fermi Gamma-ray Space Telescope. These observations reveal source no discernible spatial extension detected at significance level 12.2$\sigma$ above 500 MeV location that is consistent position explosion occurred around 1680 in Cassiopeia constellation - A. The flux and spectral shape are scenario which originates relativistic particles accelerated shell this...
The Large Area Telescope (LAT) on the Fermi Gamma-ray Space is a pair-conversion telescope designed to detect photons with energies from 20 MeV > 300 GeV. pre-launch response functions of LAT were determined through extensive Monte Carlo simulations and beam tests. point-spread function (PSF) characterizing angular distribution reconstructed as energy geometry in detector here two years on-orbit data by examining distributions γrays pulsars active galactic nuclei (AGN). Above 3 GeV, PSF...
The Nancy Grace Roman Space Telescope (Roman) formerly known as the Wide-Field Infrared Survey will answer fundamental questions about evolution of dark energy over time and expand catalog exoplanets into new regions parameter space. Using a Hubble-sized mirror 18 newly developed HgCdTe 4K × photodiode arrays (H4RG-10), measure positions shapes hundreds millions galaxies, light curves thousands supernovae, microlensing signals thousand toward bulge Galaxy. These measurements require...
The Nancy Grace Roman Space Telescope will study the dark matter content of universe, expansion history and diversity exoplanets in Galaxy using unprecedented wide-field infrared surveys. accomplish this a focal plane 18 newly developed HgCdTe detectors. Roman's detectors, H4RG-10, are 4 K×4 K format 10-micron pixel pitch devices manufactured by Teledyne Imaging Sensors. After acceptance testing at Goddard Detector Characterization Lab, flight detectors were selected for plane. Histograms...
We present a time-dependent spectral model of the nebula 3C 58 and compare it with available data. The is for leptonic in which particles are subject to synchrotron, inverse Compton, self-synchrotron adiabatic, bremsstrahlung processes. find that compatible being particle-dominated nebula, magnetic field 35 μG. A broken power-law injection fits well multi-frequency data, break energy at about 40 GeV. not expected appear VERITAS or MAGIC II, unless local IR background factor ∼20 off Galactic...
We investigate the time-dependent behavior of Crab-like pulsar wind nebulae (PWNe) generating a set models using 4 different initial spin-down luminosities ($L_0 =\{1,0.1,0.01,0.001\} \times L_{0, {\rm Crab}}$), 8 values magnetic fraction ($\eta =$ 0.001, 0.01, 0.03, 0.1, 0.5, 0.9, 0.99, and 0.999, i.e., from fully particle dominated to magnetically nebulae), 3 distinctive ages: 940, 3000, 9000 years. find that self-synchrotron Compton (SSC) contribution is irrelevant for $L_{SD}$=0.1, 1,...
We describe a new method for measuring the extragalactic background light (EBL) through detection of γ-ray inverse Compton (IC) emission due to scattering EBL photons off relativistic electrons in lobes radio galaxies. Our has no free physical parameters and is powerful tool when are characterized by high-energy sharp break or cutoff their electron energy distribution (EED). show that such feature will produce IC "imprint" spectrum which embedded how this imprint can be used derive EBL....
An analysis of the influence Landau-Migdal-Pomeranchuk (LPM) effect on development air showers initiated by astroparticles is presented. The theory Migdal studied and compared with other theoretical methods, particularly Blankenbecler-Drell approach. By means realistic computer simulations using algorithms that emulate Migdal's theory, including also so-called dielectric suppression, we study behavior relevant observables in case ultrahigh energy primaries. We find LPM can significantly...
The common approach to compute the cosmic ray distribution in a starburst galaxy or region is equivalent assuming that at any point within environment, there an accelerator inputting rays reduced rate.This rate should be compatible with overall volumeaverage injection, given by total number of accelerators were active during age.These assumptions seem reasonable, especially under supposition homogeneous and isotropic accelerators.However, this temporal evolution superposed spectrum not...
We make a time-dependent characterization of pulsar wind nebulae (PWNe) surrounding some the highest spin-down pulsars that have not yet been detected at TeV. Our aim is assessing their possible level magnetization. analyze driven by J2022+3842 in G76.9+1.0, J0540-6919 N158A (the Crab twin), J1400--6325 G310.6--1.6, and J1124--5916 G292.0+0.18, none which found TeV energies. For comparison we refer to published models G54.1+0.3, nebula, develop model for N157B Large Magellanic Cloud (LMC)....
Weak gravitational lensing has emerged as a leading probe of the growth cosmic structure. However, shear signal is very small and accurate measurement depends critically on our ability to understand how non-ideal instrumental effects affect astronomical images. WFIRST will fly focal plane containing 18 Teledyne H4RG-10 near infrared detector arrays, which present different instrument calibration challenges from previous weak observations. Previous work shown that correlation functions flat...
The influence of the geomagnetic field on development air showers is studied. well known International Geomagnetic Reference Field was included in AIRES shower simulation program as an auxiliary tool to allow calculation very accurate estimations given geographic coordinates, altitude above sea level and date a event. Our simulations indicate that deflections significantly alter some observables such as, for example, lateral distribution muons case events with large zenith angles (larger...
We reconsider the effects of photon-graviton conversion in a primordial magnetic field upon cosmic microwave background radiation. argue that plasma make process negligible.
We present a stacking analysis of EGRET $γ$-ray observations at the positions luminous and ultraluminous infrared galaxies. The latter were selected from recently presented HCN survey, which is thought to contain most active star forming regions universe. Different sorting criteria are used and, whereas no positive collective detection emission these objects we determined both individual upper limits. excess find appears in case ULIRGs ordered by redshift, value 1.8$σ$.