A. Moretti
A5038024447- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- SAS software applications and methods
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Laser Design and Applications
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Particle Detector Development and Performance
- Laser-Matter Interactions and Applications
- Advanced Fiber Laser Technologies
- Photonic and Optical Devices
- Advanced X-ray Imaging Techniques
- Atomic and Subatomic Physics Research
- Calibration and Measurement Techniques
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- Solid State Laser Technologies
- Semiconductor Lasers and Optical Devices
- Atmospheric Ozone and Climate
- CCD and CMOS Imaging Sensors
Brera Astronomical Observatory
2014-2024
National Institute for Astrophysics
2008-2024
Cosine (Netherlands)
2024
European Space Research and Technology Centre
2024
University of Leicester
2005-2023
Osservatorio astronomico di Bologna
2010-2015
University of Maryland, Baltimore County
2015
University of Bologna
2015
Sapienza University of Rome
2015
Galaxies, Etoiles, Physique et Instrumentation
2015
We present new observations of the early X-ray afterglows first 27 gamma-ray bursts (GRBs) well observed by Swift X-Ray Telescope (XRT). The show a canonical behavior, where light curve broadly consists three distinct power-law segments: (1) an initial very steep decay (∝t-α with 3 ≲ α1 5), followed (2) shallow (0.5 α2 1.0), and finally (3) somewhat steeper (1 α3 1.5). These segments are separated two corresponding break times, tbreak,1 500 s 103 tbreak,2 104 s. On top this many events have...
Gamma-ray burst (GRB) afterglows have provided important clues to the nature of these massive explosive events, providing direct information on nearby environment and indirect central engine that powers burst. We report discovery two bright x-ray flares in GRB afterglows, including a giant flare comparable total energy itself, each peaking minutes after These strong, rapid imply engines bursts long periods activity, with strong internal shocks continuing for hundreds seconds gamma-ray...
The High Energy X-ray Probe (HEX-P) is a proposed NASA probe-class mission that combines the power of high angular resolution with broad bandpass to provide necessary leap in capabilities address important astrophysical questions next decade. HEX-P achieves breakthrough performance by combining technologies developed experienced international partners. To meet science goals, payload consists suite co-aligned telescopes designed cover 0.2–80 keV bandpass. Telescope (HET) has an effective 2–80...
We present observations of the early X-ray emission for a sample 40 gamma-ray bursts (GRBs) obtained using Swift satellite which narrow-field instruments were pointed at burst within 10 minutes trigger. Using data from Burst Alert and X-Ray Telescopes, we show that light curve can be well described by an exponential relaxes into power law, often with flares superimposed. The transition time between law provides physically defined timescale duration. In most breaks to shallower decay first...
We present the X-ray source number counts in two energy bands (0.5-2 and 2-10 keV) from a very large sample: we combine data of six different surveys, both shallow wide-field deep pencil-beam, performed with three satellites (ROSAT, Chandra, XMM-Newton). The sample covers good statistics largest possible flux range so far: 2.4 × 10-17 to 10-11 ergs s-1 cm-2 soft band 2.1 10-16 8 10-12 hard band. Integrating distributions over this taking into account (small) contribution brightest sources,...
We systematically analyze the prompt emission and early afterglow data of a sample 31 GRBs detected by {\em Swift} before September 2005, estimate GRB radiative efficiency. BAT's narrow band inhibits precise determination spectral parameters, we have developed method to these parameters with hardness ratio information. The shallow decay component commonly existing in X-ray afterglows, if interpreted as continuous energy injection external shock, suggests that efficiency previously derived...
We present the catalog of sources detected in first 22 months data from hard X-ray survey (14--195 keV) conducted with BAT coded mask imager on \swift satellite. The contains 461 above 4.8 sigma level BAT. High angular resolution for every source Swift XRT or archival have allowed associations to be made known counterparts other wavelength bands over 97% detections, including discovery ~30 galaxies previously unknown as AGN and several new Galactic sources. A total 266 are associated Seyfert...
We present the first systematic investigation of morphological and timing properties flares in GRBs observed by Swift XRT. consider a large sample drawn from all detected Swift, INTEGRAL, HETE-2 prior to 2006 January 31, which had an XRT follow-up showed significant flaring. Our 33 includes long short, at low high redshift, total 69 flares. The strongest occur early phases, with clear anticorrelation between flare peak intensity time occurrence. Fitting each X-ray Gaussian model, we find...
We present observations of GRB 060124, the first event for which both prompt and afterglow emission could be observed simultaneously in their entirety by three Swift instruments. Indeed, Swift-BAT triggered on a precursor ~570s before main burst peak, this allowed to repoint narrow field instruments position ~350s occurred. 060124 also Konus-Wind, harder gamma-ray band (up 2MeV). Thanks these exceptional circumstances, temporal spectral properties can studied optical, X-ray ranges. While...
We present a detailed analysis of Swift multi-wavelength observations GRB 070110 and its remarkable afterglow. The early X-ray light curve, interpreted as the tail prompt emission, displays spectral evolution already seen in other gamma-ray bursts. optical afterglow shows shallow decay up to ~2 d after burst, which is not consistent with standard models. most intriguing feature very steep flux at ~20 ks ending an apparent plateau. abrupt drop curve rules out external shock origin plateau...
The <i>Swift</i> X-ray Telescope (XRT) is designed to make astrometric, spectroscopic, and photometric observations of emission from Gamma-ray Bursts their afterglows in the energy band 0.2-10 keV. In order provide rapid-response, automated these randomly occurring objects without ground intervention, XRT must be able observe covering some seven orders magnitude flux, extracting maximum possible science each one. This requires a variety readout modes optimise information collected response...
We present a comprehensive statistical analysis of Swift X-ray light curves gamma-ray bursts (GRBs) collecting data from more than 650 GRBs discovered by and other facilities. The unprecedented sample size allows us to constrain the rest-frame properties perspective, with particular reference intrinsic time-scales energetics different light-curve phases in common 0.3–30 keV energy band. Temporal variability episodes are also studied their constrained. Two fundamental questions drive this...
Aims. We present the Second Palermo Swift-BAT hard X-ray catalogue obtained by analysing data acquired in first 54 months of Swift mission.
We present the Second Palermo Swift-BAT hard X-ray catalogue obtained by analysing data acquired in first 54 months of Swift mission. Using our software dedicated to analysis from coded mask telescopes, we analysed BAT survey three energy bands (15-30 keV, 15-70 15-150 keV), obtaining a list 1256 detections above significance threshold 4.8 standard deviations. The identification source counterparts is pursued using two strategies: field observations soft instruments and cross-correlation...
Aims. We present a new measurement of the cosmic X-ray background (CXRB) in 1.5-7 keV energy band, performed by exploiting Swift telescope (XRT) data archive. also CXRB spectral model wider band (1.5-200 keV), obtained combining these with recently published Swift-BAT measurement.
We present the discovery of PSO J030947.49+271757.31, radio brightest (23.7 mJy at 1.4 GHz) active galactic nucleus (AGN) z>6.0. It was selected by cross-matching NRAO VLA Sky Survey and Panoramic Telescope Rapid Response System PS1 databases its high-z nature confirmed a dedicated spectroscopic observation Large Binocular Telescope. A pointed Neil Gehrels $Swift$ Observatory XRT allowed us to measure flux $\sim$3.4$\times$10$^{-14}$ erg s$^{-1}$ cm$^{-2}$ in [0.5-10] keV energy band, which...
GRB observations with Swift produced the initially surprising result that many bursts have large, late-time X-ray flares. The flares were sometimes intense, had rapid rise and decay phases, occurred late relative to prompt phase. Many GRBs several flares, which overlapping. origin of can be investigated by comparing spectra during those afterglow initial emission. In this work we analyzed all significant from first 110 observed Swift. Significant (>3 σ ) found in 33 these GRBs, 77 detected....
This paper discusses Swift observations of the gamma-ray burst GRB 050315 (z=1.949) from 80 s to 10 days after onset burst. The X-ray light curve displayed a steep early decay (t^-5) for ~200 and several breaks. However, both prompt hard X-ray/gamma-ray emission (observed by BAT) first ~ 300 XRT) can be explained exponential decays, with similar constants. Extrapolating BAT into XRT band suggests rapidly decaying, was simply continuation fading emission; this strong similarity between may...