M.-H. Grondin
A5020529042- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Neutrino Physics Research
- Astronomy and Astrophysical Research
- Cosmology and Gravitation Theories
- Particle Detector Development and Performance
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Particle physics theoretical and experimental studies
- Particle Accelerators and Free-Electron Lasers
- Astrophysics and Star Formation Studies
- Solar and Space Plasma Dynamics
- Noncommutative and Quantum Gravity Theories
- Calibration and Measurement Techniques
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Black Holes and Theoretical Physics
- Radiation Therapy and Dosimetry
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
Laboratoire de Physique des deux infinis Bordeaux
2015-2024
Centre National de la Recherche Scientifique
2014-2023
Institut National de Physique Nucléaire et de Physique des Particules
2011-2022
Université de Bordeaux
2009-2020
Friedrich-Alexander-Universität Erlangen-Nürnberg
2017
Laboratoire Univers et Particules de Montpellier
2015-2016
Université de Montpellier
2015-2016
Max Planck Institute for Nuclear Physics
2011-2015
Heidelberg University
2011-2015
Université Toulouse III - Paul Sabatier
2013
(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...
We present the third Fermi Large Area Telescope (LAT) source catalog (3FGL) of sources in 100 MeV–300 GeV range. Based on first 4 yr science data from Gamma-ray Space mission, it is deepest yet this energy Relative to Second LAT catalog, 3FGL incorporates twice as much data, well a number analysis improvements, including improved calibrations at event reconstruction level, an updated model for Galactic diffuse γ-ray emission, refined procedure detection, and methods associating with...
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,...
We present the second catalog of high-energy gamma-ray sources detected by Large Area Telescope (LAT), primary science instrument on Fermi Gamma-ray Space (Fermi), derived from data taken during first 24 months phase mission, which began 2008 August 4. Source detection is based average flux over 24-month period. The Second Fermi-LAT (2FGL) includes source location regions, defined in terms elliptical fits to 95% confidence regions and spectral power-law, exponentially cutoff or log-normal...
We present the fourth Fermi Large Area Telescope catalog (4FGL) of gamma-ray sources. Based on first eight years science data from Gamma-ray Space mission in energy range 50 MeV to 1 TeV, it is deepest yet this range. Relative 3FGL catalog, 4FGL has twice as much exposure well a number analysis improvements, including an updated model for Galactic diffuse emission, and two sets light curves (1-year 2-month intervals). The includes 5064 sources above 4 sigma significance, which we provide...
This catalog summarizes 117 high-confidence ⩾0.1 GeV gamma-ray pulsar detections using three years of data acquired by the Large Area Telescope (LAT) on Fermi satellite. Half are neutron stars discovered LAT through periodicity searches in and radio around unassociated source positions. The pulsars evenly divided into groups: millisecond pulsars, young radio-loud radio-quiet pulsars. We characterize pulse profiles energy spectra derive luminosities when distance information exists. Spectral...
Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Burst Monitor and Large Area Telescope onboard Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades gammaray energy. In September 2008, observed exceptionally luminous GRB 080916C, with largest apparent release yet measured. high-energy gamma rays to start later persist longer than lower photons. A simple spectral form fits entire...
We report on the first Fermi Large Area Telescope (LAT) measurements of so-called "extragalactic" diffuse gamma-ray emission (EGB). This component is generally considered to have an isotropic or nearly distribution sky with diverse contributions discussed in literature. The derivation EGB based detailed modeling bright foreground Galactic emission, detected LAT sources, and solar emission. find spectrum consistent a power law differential spectral index gamma = 2.41 +/- 0.05 intensity I(>100...
We present the first catalog of active galactic nuclei (AGNs) detected by Large Area Telescope (LAT), corresponding to 11 months data collected in scientific operation mode. The First LAT AGN Catalog (1LAC) includes 671 γ-ray sources located at high Galactic latitudes (|b|>10°) that are with a test statistic greater than 25 and associated statistically AGNs. Some multiple AGNs, consequently, 709 comprising 300 BL Lacertae objects, 296 flat-spectrum radio quasars, 41 AGNs other types, 72...
The dramatic increase in the number of known gamma-ray pulsars since launch Fermi Gamma-ray Space Telescope (formerly GLAST) offers first opportunity to study a sizable population these high-energy objects. This catalog summarizes 46 high-confidence pulsed detections using six months data taken by Large Area (LAT), Fermi's main instrument. Sixteen previously unknown were discovered searching for signals at positions bright sources seen with LAT, or objects suspected be neutron stars based on...
ABSTRACT Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope ( ) began a sky survey August. The Large Area (LAT) on three months produced deeper and better resolved map of γ-ray than any previous space mission. We present here initial results for energies above 100 MeV 205 most significant (statistical significance greater ∼10σ) sources these data. These are best characterized localized point-like (i.e., spatially unresolved) early mission
We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog gamma-ray sources. Based on first twelve years science data in energy range from 50 MeV to 1 TeV, it contains 6658 The analysis improves that used 4FGL over eight data: more sources are fit with curved spectra, we introduce a robust spectral parameterization pulsars, and extend points TeV. parameters, distributions, associations updated all Light curves rebuilt yr intervals (not 2 month...
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...
The first three months of sky-survey operation with the Fermi Gamma Ray Space Telescope (Fermi) Large Area (LAT) reveals 132 bright sources at |b|>10 deg test statistic greater than 100 (corresponding to about 10 sigma). Two methods, based on CGRaBS, CRATES and BZCat catalogs, indicate high-confidence associations 106 these known AGNs. This sample is referred as LAT Bright AGN Sample (LBAS). It contains two radio galaxies, namely Centaurus A NGC 1275, 104 blazars consisting 57 flat...
A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by Large Area Telescope on board Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 lasted approximately 16 days. second was September 2010 4 During these outbursts, flux nebula increased factors of four six, respectively. brevity implies that gamma rays were emitted via...
This paper presents light curves as well the first systematic characterization of variability 106 objects in high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly this sample, obtained during 11 months survey (2008 August 4–2009 July 4), are tested for and their properties quantified through autocorrelation function structure analysis. For brightest sources, 3 or 4 day binned extracted order to determine power density spectra (PDSs) fit temporal major flares. More than...
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...
Pulsars are rapidly-rotating, highly-magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there more than 1800 known radio pulsars, until recently, only seven were observed to pulse in gamma rays and these all discovered at other wavelengths. The Fermi Large Area Telescope makes it possible pinpoint through their gamma-ray pulsations. We report detection of 16 pulsars blind frequency searches using LAT. Most coincident with previously unidentified...
The inner region of the Milky Way halo harbors a large amount dark matter (DM). Given its proximity, it is one most promising targets to look for DM. We report on search annihilations DM particles using γ-ray observations towards 300 pc Way, with H.E.S.S. array ground-based Cherenkov telescopes. analysis based 2D maximum likelihood method Galactic Center (GC) data accumulated by over last 10 years (2004-2014), and does not show any significant signal above background. Assuming Einasto...
We present a catalog of sources detected above 50 GeV by the {\it Fermi}-Large Area Telescope (LAT) in 80 months data. The newly delivered Pass 8 event-level analysis allows detection and characterization GeV--2 TeV energy range. In this band, Fermi}-LAT has 360 sources, which constitute second hard (2FHL). improved angular resolution enables precise localization point ($\sim$1.7$'$ radius at 68 % C.~L.) spatially extended sources. find that 86 can be associated with counterparts other...
Gamma-ray line signatures can be expected in the very-high-energy (${E}_{\ensuremath{\gamma}}>100\text{ }\text{ }\mathrm{GeV}$) domain due to self-annihilation or decay of dark matter (DM) particles space. Such a signal would readily distinguishable from astrophysical $\ensuremath{\gamma}$-ray sources that most cases produce continuous spectra span over several orders magnitude energy. Using data collected with H.E.S.S. instrument, upper limits on linelike emission are obtained energy range...
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...
Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, associated with stellar core collapse events. We report the detection very-high-energy (VHE) GRB 190829A, between 4 and 56 hours after trigger, using High Energy Stereoscopic System (H.E.S.S.). The low luminosity redshift 190829A reduce both internal external absorption, allowing determination its intrinsic energy spectrum. Between energies 0.18 3.3 tera-electron...
We report on gamma-ray observations of the Crab Pulsar and Nebula using 8 months survey data with Fermi Large Area Telescope (LAT). The high quality light curve obtained ephemeris provided by Nancay Jodrell Bank radio telescopes shows two main peaks stable in phase energy. first peak leads pulse (281 \pm 12 21) mus, giving new constraints production site non-thermal emission pulsar magnetospheres. improved sensitivity unprecedented statistics afforded LAT enable precise measurement spectral...