M. N. Mazziotta
A5089675278- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Gamma-ray bursts and supernovae
- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Solar and Space Plasma Dynamics
- Radiation Therapy and Dosimetry
- Astronomical Observations and Instrumentation
- Particle Accelerators and Free-Electron Lasers
- Galaxies: Formation, Evolution, Phenomena
- Nuclear Physics and Applications
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Atomic and Subatomic Physics Research
- Muon and positron interactions and applications
- High-Energy Particle Collisions Research
- Cosmology and Gravitation Theories
- Atmospheric Ozone and Climate
- Planetary Science and Exploration
- CCD and CMOS Imaging Sensors
Istituto Nazionale di Fisica Nucleare, Sezione di Bari
2016-2025
Istituto Nazionale di Fisica Nucleare
2007-2024
University of Salerno
2024
Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Salerno
2024
Istituto Nazionale di Fisica Nucleare, Sezione di Cagliari
2024
Istituto Nazionale di Fisica Nucleare, Sezione di Pavia
2023
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
1995-2023
Istituto Nazionale di Fisica Nucleare, Sezione di Lecce
2023
University of Geneva
2023
University of Salento
2023
The dwarf spheroidal satellite galaxies (dSphs) of the Milky Way are some most dark matter (DM) dominated objects known. We report on gamma-ray observations dSphs based 6 years Fermi Large Area Telescope data processed with new Pass 8 event-level analysis. None significantly detected in gamma rays, and we present upper limits DM annihilation cross section from a combined analysis 15 dSphs. These constraints among strongest robust to date lie below canonical thermal relic for mass $\lesssim$...
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...
The γ-ray sky can be decomposed into individually detected sources, diffuse emission attributed to the interactions of Galactic cosmic rays with gas and radiation fields, a residual all-sky component commonly called isotropic background (IGRB). IGRB comprises all extragalactic emissions too faint or resolved in given survey, as well any foregrounds that are approximately isotropic. first measurement Large Area Telescope (LAT) on board Fermi Gamma-ray Space (Fermi) used 10 months sky-survey...
The gamma-ray sky >100 MeV is dominated by the diffuse emissions from interactions of cosmic rays with interstellar gas and radiation fields Milky Way. Observations these provide a tool to study cosmic-ray origin propagation, medium. We present measurements first 21 months Fermi-LAT mission compare models emission generated using GALPROP code. are fitted data incorporate astrophysical input for distribution sources, fields. To assess uncertainties associated input, grid created varying...
The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years scientific operation is presented. LAT AGN (2LAC) includes 1017 γ-ray sources located at high Galactic latitudes (|b| > 10°) that are with a test statistic (TS) greater than 25 and associated statistically AGNs. However, some these affected analysis issues multiple Consequently, we define Clean Sample which 886 AGNs, comprising 395 BL Lacertae objects (BL Lac objects), 310...
We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because instrument does not have an onboard magnet, we distinguish two species by exploiting Earth's shadow, which is offset in opposite directions for charges due to magnetic field. estimate subtract proton background using different methods that produce consistent results. report electron-only spectrum, positron-only fraction between 20 GeV 200 GeV. confirm rises energy 20-100 range. The...
The third catalog of active galactic nuclei (AGNs) detected by the Fermi-LAT (3LAC) is presented. It based on (3FGL) sources between 100 MeV and 300 GeV with a Test Statistic (TS) greater than 25, 2008 August 4 2012 July 31. 3LAC includes 1591 AGNs located at high Galactic latitudes (|b|>10{\deg}), 71% increase over second 2 years data. There are 28 duplicate associations, thus 1563 2192 high-latitude gamma-ray 3FGL AGNs. Most them (98%) blazars. About half newly blazars unknown type, i.e.,...
Satellite galaxies of the Milky Way are among most promising targets for dark matter searches in gamma rays. We present a search consisting weakly interacting massive particles, applying joint likelihood analysis to 10 satellite with 24 months data Fermi Large Area Telescope. No signal is detected. Including uncertainty distribution, robust upper limits placed on annihilation cross sections. The 95% confidence level range from about 10(-26) cm3 s(-1) at 5 GeV 5×10(-23) 1 TeV, depending final...
The dwarf spheroidal satellite galaxies of the Milky Way are some most dark-matter-dominated objects known. Due to their proximity, high dark matter content, and lack astrophysical backgrounds, widely considered be among promising targets for indirect detection via $\ensuremath{\gamma}$ rays. Here we report on $\ensuremath{\gamma}$-ray observations 25 based 4 years Fermi Large Area Telescope (LAT) data. None significantly detected in rays, present flux upper limits between 500 MeV GeV. We...
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 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...
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...
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 detailed observations of the bright short-hard gamma-ray burst GRB 090510 made with Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board Fermi observatory. is first detected by LAT that shows strong evidence for a deviation from Band spectral fitting function during prompt emission phase. The time-integrated spectrum fit sum $\Epeak = 3.9\pm 0.3$\,MeV, which highest yet measured, hard power-law component photon index $-1.62\pm 0.03$ dominates below...
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...
Dark matter in the Milky Way may annihilate directly into gamma rays, producing a monoenergetic spectral line. Therefore, detecting such signature would be strong evidence for dark annihilation or decay. We search lines Fermi Large Area Telescope observations of halo energy range 200 MeV to 500 GeV using analysis methods from our most recent line searches. The main improvements relative previous works are use 5.8 years data reprocessed with Pass 8 event-level and additional resulting...
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...
We report on the gamma-ray activity of high-synchrotron-peaked BL Lacertae object Mrk 421 during first 1.5 years Fermi operation, from 2008 August 5 to 2010 March 12. find that Large Area Telescope (LAT) spectrum above 0.3 GeV can be well-described by a power-law function with photon index Gamma=1.78 +/- 0.02 and average flux F(>0.3 GeV)=(7.23 0.16) x 10^{-8} ph cm^{-2} s^{-1}. Over this time period, Fermi-LAT was evaluated 7-day-long intervals, showing significant variations in (up factor...
The Fermi bubbles are two large structures in the gamma-ray sky extending to 55° above and below Galactic center. We analyze 50 months of Large Area Telescope data between 100 MeV 500 GeV 10° latitude derive spectrum morphology bubbles. thoroughly explore systematic uncertainties that arise when modeling diffuse emission through separate approaches. is well described by either a log parabola or power law with an exponential cutoff. exclude simple more than 7σ significance. cutoff has index...
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 fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area (4LAC) between 2008 August 4 and 2016 2 contains 2863 objects located at high Galactic latitudes (|b|>10{\deg}). It includes 85% more sources than previous 3LAC based on years data. AGNs represent least 79% high-latitude in Fermi-Large Source Catalog (4FGL), which covers energy range from 50 MeV to 1 TeV. In addition, 344 gamma-ray are found low latitudes. Most 4LAC blazars (98%),...
We report the discovery with Fermi/LAT of gamma-ray emission from three radio-loud narrow-line Seyfert 1 galaxies: PKS 1502+036 (z=0.409), 1H 0323+342 (z=0.061) and 2004-447 (z=0.24). In addition to PMN J0948+0022 (z=0.585), first source this type be detected in gamma rays, they may form an emerging new class active galactic nuclei (AGN). These findings can have strong implications on our knowledge about relativistic jets unified model AGN.
The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little escape from the shock and evolution through turbulent medium surrounding massive stars. Gamma can probe spreading ambient gas radiation fields. Fermi Large Area Telescope (LAT) has observed star-forming region Cygnus X. 1- 100-gigaelectronvolt images reveal 50-parsec-wide cocoon freshly accelerated that flood cavities carved stellar winds...