A. Belfiore
A5083460968- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- High-pressure geophysics and materials
- Particle Detector Development and Performance
- Radio Astronomy Observations and Technology
- Geophysics and Gravity Measurements
- Astrophysics and Star Formation Studies
- Particle Accelerators and Free-Electron Lasers
- Scientific Computing and Data Management
- Superconducting Materials and Applications
- Particle physics theoretical and experimental studies
- Time Series Analysis and Forecasting
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Atomic and Molecular Physics
- Nuclear physics research studies
- Mechanics and Biomechanics Studies
- Seismology and Earthquake Studies
Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
2015-2024
UK Astronomy Technology Centre
2020-2022
National Institute for Astrophysics
2011-2020
Sto (Germany)
2020
University of California, Santa Cruz
2010-2017
University of Manchester
2017
Istituto Universitario di Studi Superiori di Pavia
2008-2017
University of Hong Kong
2017
Universidad Complutense de Madrid
2017
Leibniz University Hannover
2017
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...
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...
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...
The Cherenkov Telescope Array, CTA, will be the major global observatory for very high energy gamma-ray astronomy over next decade and beyond. scientific potential of CTA is extremely broad: from understanding role relativistic cosmic particles to search dark matter. an explorer extreme universe, probing environments immediate neighbourhood black holes voids on largest scales. Covering a huge range in photon 20 GeV 300 TeV, improve all aspects performance with respect current instruments....
Spinning up an extragalactic neutron star Ultraluminous x-ray sources (ULXs) are strange objects in other galaxies that cannot be explained by conventional accretion onto stellar-mass objects. This has led to exotic interpretations, such as the long-sought intermediate-mass black holes. Israel et al. observed a ULX nearby galaxy NGC 5907 and found it is instead star. The spinning accreting material so fast its spin period quickly accelerating. only way can consume enough explain these...
NGC 7793 P13 is a variable (luminosity range ~100) ultraluminous X-ray source (ULX) proposed to host stellar-mass black hole of less than 15 M$_{\odot}$ in binary system with orbital period 64 d and 18-23 B9Ia companion. Within the EXTraS project we discovered pulsations at ~0.42 s two XMM-Newton observations P13, during which was detected $L_{\mathrm{X}}\sim2.1\times10^{39}$ $5\times10^{39}$ erg s$^{-1}$ (0.3-10 keV band). These findings unambiguously demonstrate that compact object neutron...
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...
We present a catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during first three years Fermi Gamma-ray Space mission. The Fermi-LAT >10GeV (1FHL) has 514 sources. For each source we location, spectrum, measure variability, and associations with cataloged other wavelengths. found that 449 (87%) could be associated known sources, which 393 (76% 1FHL sources) are active galactic nuclei. Of 27 pulsars, find 20 (12) to have...
Abstract We discovered 2.8 s pulsations in the X-ray emission of ultraluminous source (ULX) M51 ULX-7 within UNSEeN project, which was designed to hunt for new pulsating ULXs (PULXs) with XMM-Newton. The pulse shape is sinusoidal, and large variations its amplitude were observed even single exposures (pulsed fraction from less than 5% 20%). Source variable, generally at an luminosity between 10 39 40 erg −1 , located outskirts spiral galaxy M51a a distance 8.6 Mpc. According our analysis,...
The Large Area Telescope on board the Fermi satellite observed a gamma-ray flare in Crab Nebula lasting for approximately nine days April of 2011. source, which at optical wavelengths has size ≈11 lt-yr across, doubled its flux within eight hours. peak photon was (186 ± 6) × 10−7 cm−2 s−1 above 100 MeV, corresponds to 30-fold increase compared average value. During flare, new component emerged spectral energy distribution, peaked an (375 26) MeV maximum. observations imply that emission...
We report the discovery of eight gamma-ray pulsars in blind frequency searches using LAT, onboard Fermi Gamma-ray Space Telescope. Five are young (tau_c<100 kyr), energetic (Edot>10^36 erg/s), and located within Galactic plane (|b|<3 deg). The remaining three older, less energetic, off plane. associated with sources included LAT bright source list, but only one, PSR J1413-6205, is clearly an EGRET source. J1023-5746 has smallest characteristic age (tau_c=4.6 kyr) most (Edot=1.1E37 erg/s) all...
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)...
Using the Parkes Radio Telescope, we have carried out deep observations of 11 unassociated gamma-ray sources. Periodicity searches these data discovered two millisecond pulsars, PSR J1103−5403 (1FGL J1103.9−5355) and J2241−5236 J2241.9−5236), a long-period pulsar, J1604−44 J1604.7−4443). In addition, searched for but did not detect any radio pulsations from six pulsars by Fermi satellite to level ∼0.04 mJy (for with 10 per cent duty cycle). The timing pulsar has shown that its position is 9...
Gamma-ray binaries are stellar systems containing a neutron star or black hole with gamma-ray emission produced by an interaction between the components. These rare, even though binary evolution models predict dozens in our Galaxy. A search for Fermi Large Area Telescope (LAT) shows that 1FGL J1018.6-5856 exhibits intensity and spectral modulation 16.6 day period. We identified variable X-ray counterpart, which sharp maximum coinciding emission, as well O6V((f)) optical counterpart radio is...
[Abridged] We report on a multiwavelength observation of the blazar 3C 454.3 (which we dubbed "crazy diamond") carried out November 2007 by means astrophysical satellites AGILE, INTEGRAL, Swift, WEBT Consortium, and optical-NIR telescope REM. is detected at $\sim 19-σ$ level during 3-week observing period, with an average flux above 100 MeV $F_{\rm E>100MeV} = (170 \pm 13) \times 10^{-8}$ \phcmsec. The gamma-ray spectrum can be fit single power-law photon index $Γ_{\rm GRID} 1.73 0.16$...
Context. The Cygnus region hosts a giant molecular-cloud complex that actively forms massive stars. Interactions of cosmic rays with interstellar gas and radiation fields make it shine at γ-ray energies. Several pulsars other energetic sources are seen in this direction.
Using a new XMM-Newton observation, we have characterized the X-ray properties of middle-aged radio-quiet gamma-ray pulsar J0357+3205 (named Morla) and its tail. The emission from is consistent with magnetospheric non-thermal origin plus thermal hot spot (or spots). lack component whole surface makes Morla coldest neutron star in age range. We found marginal evidence for double-peaked modulation emission. study 9'-long tail confirmed extended near itself. shows very asymmetric brightness...
We present multi-wavelength observations of the unassociated γ-ray source 3FGL J2039.6−5618 detected by Fermi Large Area Telescope. The properties suggest that it is a pulsar, most likely millisecond for which neither radio nor pulsations have been detected. observed with XMM-Newton and discovered several candidate X-ray counterparts within/close to error box. brightest these sources variable period 0.2245 ± 0.0081 days. Its spectrum can be described power law photon index ΓX = 1.36 0.09,...
Abstract We report on the orbit of binary system powering most extreme ultraluminous X-ray pulsar known to date: NGC 5907 ULX-1 (hereafter ULX1). ULX1 has been target a substantial multi-instrument campaign, mainly in band, but no clear counterparts are other bands. Although is highly variable and pulsations can be transient (regardless source flux), timing data collected so far allow us investigate this system. find an orbital period <?CDATA...
The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space opened a new era for pulsar astronomy, detecting γ-ray pulsations from more than 60 pulsars, ∼40% of which are not seen at radio wavelengths. One most interesting sources discovered by LAT is PSR J0357+3205, radio-quiet, middle-aged (τC ∼ 0.5 Myr) standing out its very low spin-down luminosity ( erg s−1), indeed lowest among non-recycled pulsars. A deep X-ray observation with Chandra (0.5–10 keV), coupled sensitive...
The discovery of the gamma-ray pulsar PSR J1836+5925, powering formerly unidentified EGRET source 3EG J1835+5918, was one early accomplishments Fermi Large Area Telescope (LAT). Sitting 25 degrees off Galactic plane, J1836+5925 is a 173 ms with characteristic age 1.8 million years, spindown luminosity 1.1$\times10^{34}$ erg s$^{-1}$, and large off-peak emission component, making it quite unusual among known population. We present an analysis year LAT data, including updated timing solution,...
We present the first detection of an X-ray flare from ultracool dwarf spectral class L. The event was identified in EXTraS database XMM-Newton variable sources, and its optical counterpart, J0331−27, found through a cross-match with Dark Energy Survey Year 3 release. Next to earlier four-photon Kelu-1, J0331−27 is only second L detected X-rays, much more distant than other dwarfs detections (photometric distance 240 pc). From spectrum VIMOS instrument at VLT, we determine type be L1. has...
Temporal variability in flux and spectral shape is ubiquitous the X-ray sky carries crucial information about nature emission physics of sources. The EPIC instrument on board XMM-Newton observatory most powerful tool for studying even faint Each day, it collects a large amount hundreds new serendipitous sources, but resulting huge (and growing) dataset largely unexplored time domain. project called Exploring transient variable (EXTraS) systematically extracted all temporal domain archive....
The ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) Mini-Array will be composed of nine imaging atmospheric Cherenkov telescopes at the Observatorio del Teide site. array best suited for astrophysical observations in 0.3–200 TeV range with an angular resolution few arc-minutes and energy 10-15%. A core-science programme first four years devoted to limited number key targets, addressing most important open scientific questions very-high domain. At same time, thanks wide field...
The middle-aged PSR J0357+3205 is a nearby, radio-quiet, bright γ-ray pulsar discovered by the Fermi mission. Our previous Chandra observation revealed huge, very peculiar structure of diffuse X-ray emission originating at position and extending for >9' on plane sky. To better understand nature such nebula, we have studied proper motion parent pulsar. We performed relative astrometry images field spanning time baseline 2.2 yr, unveiling significant angular displacement counterpart,...