M. Razzano
A5037015298- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Particle Detector Development and Performance
- High-pressure geophysics and materials
- Seismic Waves and Analysis
- Astronomical Observations and Instrumentation
- Particle physics theoretical and experimental studies
- Geophysics and Sensor Technology
- Neutrino Physics Research
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Galaxies: Formation, Evolution, Phenomena
- Radiation Detection and Scintillator Technologies
- Astronomy and Astrophysical Research
- Statistical and numerical algorithms
- Seismology and Earthquake Studies
- Particle Accelerators and Free-Electron Lasers
- Astro and Planetary Science
- Superconducting Materials and Applications
Istituto Nazionale di Fisica Nucleare
2007-2024
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
2015-2024
University of Pisa
2015-2024
European Gravitational Observatory
2022
University of California, Santa Cruz
2008-2021
University of Hong Kong
2021
University of Zielona Góra
2021
Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
2021
Institut de Recherche sur les Lois Fondamentales de l'Univers
2019
Université Paris-Saclay
2019
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...
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...
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%),...
Dark matter particle annihilation or decay can produce monochromatic gamma-ray lines and contribute to the diffuse background. Flux upper limits are presented for spectral from 7 200 GeV background 4.8 264 obtained two years of Fermi Large Area Telescope data integrated over most sky. We give cross-section lifetime lower dark models that spectrum, including proposed as explanations PAMELA cosmic-ray data.
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...
We report on the search for spectral irregularities induced by oscillations between photons and axionlike-particles (ALPs) in γ-ray spectrum of NGC 1275, central galaxy Perseus cluster. Using 6 years Fermi Large Area Telescope data, we find no evidence ALPs exclude couplings above 5×10^{-12} GeV^{-1} ALP masses 0.5≲m_{a}≲5 neV at 95% confidence. The limits are competitive with sensitivity planned laboratory experiments, and, together other bounds, strongly constrain possibility that can...
Abstract The Large Area Telescope (LAT) aboard the Fermi spacecraft routinely observes high-energy emission from gamma-ray bursts (GRBs). Here we present second catalog of LAT-detected GRBs, covering first 10 yr operations, 2008 to 2018 August 4. A total 186 GRBs are found; these, 91 show in range 30–100 MeV (17 which seen only this band) and 169 detected above 100 MeV. Most these sources were discovered by other instruments ( /GBM, Swift /BAT, AGILE, INTEGRAL ) or reported Interplanetary...
We present a measurement of the cosmic-ray electron+positron spectrum between 7 GeV and 2 TeV performed with almost seven years data collected Fermi Large Area Telescope. find that is well fit by broken power law break energy at about 50 GeV. Above GeV, described single spectral index $3.07 \pm 0.02 \; (\text{stat+syst}) 0.04 (\text{energy measurement})$. An exponential cutoff lower than 1.8 excluded 95\% CL.
Machine learning has emerged as a popular and powerful approach for solving problems in astrophysics. We review applications of machine techniques the analysis ground-based gravitational-wave detector data. Examples include improving sensitivity Advanced LIGO Virgo searches, methods fast measurements astrophysical parameters sources, algorithms reduction characterization non-astrophysical noise. These demonstrate how may be harnessed to enhance science that is possible with current future detectors.
The Fermi Large Area Telescope (LAT) light curve repository (LCR) is a publicly available, continually updated library of gamma-ray curves variable Fermi-LAT sources generated over multiple timescales. LCR aims to provide publication-quality binned on timescales 3 days, 7 and 30 days for 1525 deemed in the source catalog first 10 years observations. consists through full likelihood analyses that model surrounding region, providing fluxes photon indices each time bin. intended as resource...
GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments Large Area (LAT) and Burst Monitor (GBM). The burst consisted of one major emission episode which lasted for ~24.5 seconds (in GBM) had a peak flux 5.7\pm0.2 x 10^{-5} erg/s/cm^2. time-resolved spectrum is best modeled with combination Band function blackbody spectrum. energy component initially 15\pm2 MeV, highest value ever detected in GRB. This measurement made possible combining GBM/BGO data LAT Low...
Current theories predict relativistic hadronic particle populations in clusters of galaxies addition to the already observed leptons. In these scenarios interactions give rise neutral pions which decay into γ rays that are potentially observable with Large Area Telescope (LAT) on board Fermi space telescope. We present a joint likelihood analysis searching for spatially extended γ-ray emission at locations 50 galaxy four years Fermi-LAT data under assumption universal cosmic-ray (CR) model...
ABSTRACT We present results from γ -ray observations of the Coma cluster incorporating six years Fermi -LAT data and newly released “Pass 8” event-level analysis. Our analysis region reveals low-significance residual structures within virial radius that are too faint for a detailed investigation with current data. Using likelihood approach is free assumptions on spectral shape we derive upper limits flux expected energetic particle interactions in cluster. also consider benchmark spatial...
We search for evidence of dark matter (DM) annihilation in the isotropic gamma-ray background (IGRB) measured with 50 months Fermi Large Area Telescope (LAT) observations. An improved theoretical description cosmological DM signal, based on two complementary techniques and assuming generic weakly interacting massive particle (WIMP) properties, renders more precise predictions compared to previous work. More specifically, we estimate cosmologically-induced intensity have an uncertainty a...
The detection of gravitational waves has inaugurated the era astronomy and opened new avenues for multimessenger study cosmic sources. Thanks to their sensitivity, Advanced LIGO Virgo interferometers will probe a much larger volume space expand capability discovering wave emitters. characterization these detectors is primary task in order recognize main sources noise optimize sensitivity interferometers. Glitches are transient events that can impact data quality classification an important...
An incremental version of the fourth catalog active galactic nuclei (AGNs) detected by Fermi-Large Area Telescope is presented. This (4LAC-DR3) derives from third data release 4FGL based on 12 years E>50 MeV gamma-ray data, where spectral parameters, energy distributions (SEDs), yearly light curves, and associations have been updated for all sources. The new reported AGNs include 587 blazar candidates four radio galaxies. We describe properties sample outline changes affecting previously...
We report the discovery of nine previously unknown gamma-ray pulsars in a blind search data from Fermi Large Area Telescope (LAT). The were found with novel hierarchical method originally developed for detecting continuous gravitational waves rapidly rotating neutron stars. Designed to find isolated spinning at up kHz frequencies, new is computationally efficient and incorporates several advances, including metric-based gridding parameter space (frequency, frequency derivative, sky location)...
Long-term monitoring of PSR J2021+4026 in the heart Cygnus region with Fermi Large Area Telescope unveiled a sudden decrease flux above 100 MeV over timescale shorter than week. The "jump" was near MJD 55850 (2011 October 16), decreasing from (8.33 ± 0.08) × 10−10 erg cm−2 s−1 to (6.86 0.13) s−1. Simultaneously, frequency spindown rate increased (7.8 0.1) 10−13 Hz (8.1 Significant (>5σ) changes pulse profile and marginal (<3σ) emission spectrum occurred at same time. There is also evidence...