R. Salvaterra
A5070191867- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Cosmology and Gravitation Theories
- Astrophysics and Star Formation Studies
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- SAS software applications and methods
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Mechanics and Biomechanics Studies
- Particle Accelerators and Free-Electron Lasers
- Scientific Computing and Data Management
- Advanced X-ray Imaging Techniques
- Adaptive optics and wavefront sensing
- Nuclear Physics and Applications
- Time Series Analysis and Forecasting
- Statistical and numerical algorithms
Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
2015-2024
National Institute for Astrophysics
2015-2024
Pontificia Universidad Católica de Chile
2021
Centrum Badań Kosmicznych
2018
Polish Academy of Sciences
2018
Astronomical Observatory of Capodimonte
2018
Trieste Astronomical Observatory
2017
Consejo Superior de Investigaciones Científicas
2016
China Academy of Space Technology
2016
University of Insubria
2005-2015
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...
We report our observation of the short gamma-ray burst (GRB) GRB 170817A, associated to binary neutron star merger gravitational wave (GW) event GW 170817, performed in X-ray band with XMM-Newton 135 d after (on 29 December, 2017). find evidence for a flattening light curve respect previously observed brightening. This is also supported by nearly simultaneous optical Hubble Space Telescope and successive Chandra low-frequency radio observations recently reported literature. Since...
The binary neutron star merger event GW170817 was detected through both electromagnetic radiation and gravitational waves. Its afterglow emission may have been produced by either a narrow relativistic jet or an isotropic outflow. High-spatial-resolution measurements of the source size displacement can discriminate between these scenarios. We present very-long-baseline interferometry observations, performed 207.4 days after using global network 32 radio telescopes. apparent is constrained to...
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 mergers of binary compact objects such as neutron stars and black holes are central interest to several areas astrophysics, including the progenitors gamma-ray bursts (GRBs), sources high-frequency gravitational waves likely production sites for heavy element nucleosynthesis via rapid capture (the r-process). These elements include some great geophysical, biological cultural importance, thorium, iodine gold. Here we present observations exceptionally bright burst GRB 230307A. We show...
Abstract Gamma-ray bursts (GRBs) are classified into long and short events. Long GRBs (LGRBs) associated with the end states of very massive stars, while (SGRBs) linked to merger compact objects. GRB 200826A was a peculiar event, because by definition it an SGRB, rest-frame duration ∼0.5 s. However, this event energetic soft, which is consistent LGRBs. The relatively low redshift ( z = 0.7486) motivated comprehensive, multiwavelength follow-up campaign characterize its host, search for...
We investigate the metallicity properties of host galaxies long gamma-ray bursts (GRBs) in light fundamental relation (FMR), tight dependence on mass and star formation rate (SFR) recently discovered for Sloan Digital Sky Survey with stellar masses above 109.2 M⊙. As most GRB hosts have below this limit, FMR can only be used after an extension towards lower masses. With aim, we study down to ∼108.3 M⊙, finding that does extend smoothly at masses, albeit a much larger scatter. then compare...
We present a carefully selected sub-sample of Swift long gamma-ray bursts (GRBs) that is complete in redshift. The sample constructed by considering only with favorable observing conditions for ground-based follow-up searches, which are bright the 15–150 keV Swift/BAT band, i.e., 1-s peak photon fluxes excess to 2.6 photons s−1 cm−2. composed 58 bursts, 52 them redshift completeness level 90%, while another two have constraint, reaching 95%. For three we no constraint on high allows us first...
We use a nearly complete sample of gamma-ray bursts (GRBs) detected by the Swift satellite to study correlations between spectral peak energy Epeak prompt emission, isotropic energetics Eiso and luminosity Liso. This GRB is characterized high level completeness in redshift (90 per cent). allows us probe an unbiased way issue related physical origin these against selection effects. find that one burst, 061021, outlier Epeak–Eiso correlation. Despite this case, we strong Epeak–Liso for sample....
Recent observations have gathered a considerable sample of high redshift galaxy candidates and determined the evolution their luminosity function (LF). To interpret these findings, we use cosmological SPH simulations including, in addition to standard physical processes, detailed treatment Pop III-Pop II transition early objects. The simulated high-z galaxies match remarkably well amplitude slope observed LF range 5<z<10. shifts towards fainter luminosities with increasing redshift, while...
Long-duration Gamma-Ray Bursts (GRBs) are an extremely rare outcome of the collapse massive stars, and typically found in distant Universe. Because its intrinsic luminosity ($L\sim 3 \times 10^{53}$ erg s$^{-1}$) relative proximity ($z=0.34$), GRB 130427A was a unique event that reached highest fluence observed gamma-ray band. Here we present comprehensive multiwavelength view with Swift, 2-m Liverpool Faulkes telescopes by other ground-based facilities, highlighting evolution burst emission...
We present a carefully selected sample of short gamma-ray bursts (SGRBs) observed by the Swift satellite up to June 2013. Inspired criteria we used build similar bright long GRBs (the BAT6 sample), SGRBs with favorable observing conditions for redshift determination on ground, ending 36 events, almost half which measure. The completeness increases about 70% (with an average value z = 0.85) restricting those events that are in 15-150 keV Burst Alert Telescope energy band. Such flux-limited...
We derive the luminosity function φ(L) and redshift distribution Ψ(z) of short gamma-ray bursts (SGRBs) using all available observer-frame constraints (i.e. peak flux, fluence, energy duration distributions) large population Fermi SGRBs rest-frame properties a complete sample detected by Swift. show that steep ∝ L− α with ≥ 2.0 is excluded if full set considered. implement Markov chain Monte Carlo method to functions assuming intrinsic Ep−Liso Ep−Eiso correlations hold or, alternatively,...
Knowledge of the bulk Lorentz factor $\Gamma_{0}$ GRBs allows us to compute their comoving frame properties shedding light on physics. Upon collisions with circumburst matter, fireball a GRB starts decelerate, producing peak or break (depending density profile) in curve afterglow. Considering all bursts known redshift and an early coverage emission, we find 67 optical GeV curves at time $t_{\rm p}$. For another 106 set upper limit p}^{\rm UL}$. We show that p}$ is due dynamics deceleration...
In this paper, we compute rest-frame extinctions for the afterglows of a sample Swift gamma-ray bursts (GRBs) complete in redshift. The selection criteria are based on observational high-energy parameters prompt emission and therefore our should not be biased against dusty sight-lines. It is expected that inferences hold general population GRBs. Our main result optical/near-infrared extinction GRB does follow single distribution. 87 per cent events absorbed by less than 2 mag, 50 suffer from...
Multi-messenger astronomy received a great boost following the discovery of kilonova AT2017gfo, optical counterpart gravitational wave source GW170817 associated with short gamma-ray burst GRB 170817A. AT2017gfo was first that could be extensively monitored in time both photometrically and spectroscopically. Previously, only few candidates have been observed against glare afterglows. In this work, we aim to search fingerprints AT2017gfo-like emissions optical/NIR light curves 39 GRBs known...
THESEUS, one of the two space mission concepts being studied by ESA as candidates for next M5 within its Comsic Vision programme, aims at fully exploiting Gamma-Ray Bursts (GRB) to solve key questions about early Universe, well becoming a cornerstone multi-messenger and time-domain astrophysics. By investigating first billion years Universe through high-redshift GRBs, THESEUS will shed light on main open issues in modern cosmology, such population primordial low mass luminosity galaxies,...
Abstract We present James Webb Space Telescope (JWST) and Hubble (HST) observations of the afterglow GRB 221009A, brightest gamma-ray burst (GRB) ever observed. This includes first mid-IR spectra any GRB, obtained with JWST/Near Infrared Spectrograph (0.6–5.5 micron) Mid-Infrared Instrument (5–12 micron), 12 days after burst. Assuming that intrinsic spectral slope is a single power law, F ν ∝ − β , we obtain ≈ 0.35, modified by substantial dust extinction A V = 4.9. suggests above notional...