M. Marongiu
A5023312673- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Spacecraft Design and Technology
- Neutrino Physics Research
- High-pressure geophysics and materials
- GNSS positioning and interference
- Computational Physics and Python Applications
Osservatorio Astronomico di Cagliari
2017-2024
University of Ferrara
2017-2022
International Center for Relativistic Astrophysics
2018-2021
Abstract We report multicolor optical imaging and polarimetry observations of the afterglow first TeV-detected gamma-ray burst (GRB), GRB 190114C, using RINGO3 MASTER II polarimeters. Observations begin 31 s after onset continue until ∼7000 postburst. The light curves reveal a chromatic break at ∼400–500 s, with initial temporal decay α = 1.669 ± 0.013 flattening to ∼ 1 postbreak, which we model as combination reverse forward shock components magnetization parameter R B 70. observed...
We present radio and optical afterglow observations of the TeV-bright long Gamma Ray Burst (GRB) 190114C at a redshift $z=0.425$, which was detected by MAGIC telescope. Our with ALMA, ATCA, uGMRT were obtained our low frequency observing campaign range from $\sim1$ to $\sim140$ days after burst done three telescopes spanning up $\sim25$ burst. Long term radio/mm reveal complex nature afterglow, does not follow spectral temporal closure relations expected standard model. find that...
Context . Gamma-ray bursts (GRBs) are ideal probes of the Universe at high redshift (ɀ), pinpointing locations earliest star-forming galaxies and providing bright backlights with simple featureless power-law spectra that can be used to spectrally fingerprint intergalactic medium host galaxy during period reionization. Future missions such as Gamow Explorer (hereafter Gamow) being proposed unlock this potential by increasing rate identification high-ɀ (ɀ > 5) GRBs in order rapidly trigger...
No robust detection of prompt electromagnetic counterparts to fast radio bursts (FRBs) has yet been obtained, in spite several multi-wavelength searches carried out so far. Specifically, X/gamma-ray are predicted by some models. We planned on searching for gamma-ray the Insight-Hard X-ray Modulation Telescope (Insight-HXMT) data, taking advantage unique combination large effective area keV-MeV energy range and sub-ms time resolution. selected 39 FRBs that were promptly visible from...
In 2016 September, the microquasar Cygnus X-3 underwent a giant radio flare, which was monitored for 6 d with Medicina Radio Astronomical Station and Sardinia Telescope. Long observations were performed in order to follow evolution of flare on an hourly scale, covering six frequency ranges from 1.5 25.6 GHz. The emission reached maximum 13.2 ± 0.7 Jy at 7.2 GHz 10 1 18.6 Rapid flux variations observed high frequencies peak together rapid spectral index: α steepened 0.3 0.6 (with Sν ∝ ν−α)...
The contemporaneous detection of gravitational waves and gamma rays from the GW170817/GRB 170817A, followed by kilonova emission a day after, confirmed compact binary neutron-star mergers as progenitors short-duration gamma-ray bursts (GRBs), cosmic sources heavy r-process nuclei. However, nature (and lifespan) merger remnant energy reservoir powering these bright flashes remains debated, while first minutes after are unexplored at optical wavelengths. Here, we report earliest discovery...
Observations of supernova remnants (SNRs) are a powerful tool for investigating the later stages stellar evolution, properties ambient interstellar medium, and physics particle acceleration shocks. For fraction SNRs, multi-wavelength coverage from radio to ultra high-energies has been provided, constraining their contributions production Galactic cosmic rays. Although emission is most common identifier SNRs prime probe refining models, high-resolution images at frequencies above 5 GHz...
Context. Fast Radio Bursts (FRBs) are millisecond-long bursts uniquely detected at radio frequencies. FRB 131104 is the only case for which a $\gamma$-ray transient positionally and temporally consistent was claimed. This high-energy had duration of $\sim400$~s 15-150~keV fluence $S_{\gamma}\sim4\times10^{-6}$ erg $\mathrm{cm}^{-2}$. However, association with still debated. Aims. We aim testing systematic presence an associated counterpart throughout sample population. Methods. used approach...
Context. The Sun is an extraordinary workbench, on which several fundamental astronomical parameters can be measured with high precision. Among these parameters, the solar radius R ⊙ plays important role in aspects, for instance, evolutionary models. Moreover, it conveys information about structure of different layers that compose interior and its atmosphere. Despite efforts to obtain accurate measurements , subject still debated, are puzzling and/or lacking many frequency ranges. Aims. We...
The main characteristics in the radio continuum spectra of Supernova Remnants (SNRs) result from simple synchrotron emission. In addition, electron acceleration mechanisms can shape specific ways, especially at high frequencies. These features are connected to age and peculiar conditions local interstellar medium interacting with SNR. Whereas bulk emission is expected up 20–50 GHz, sensitive high-resolution images SNRs above 10 GHz lacking not easily achievable, confused regions Galactic...
No transient electromagnetic emission has yet been found in association to fast radio bursts (FRBs), the only possible exception (3sigma confidence) being putative gamma-ray signal detected Swift/BAT data energy band 15-150 keV at time and position of FRB131104. Systematic searches for hard X/gamma-ray counterparts other FRBs ended up with just lower limits on radio/gamma-ray fluence ratios. In 2001, earliest discovered FRBs, BeppoSAX Gamma-Ray Burst Monitor (GRBM) was one most sensitive...
Abstract The coming decades will establish the exploration of gravitational wave (GW) Universe over a broad frequency range by ground and space interferometers. Meanwhile, wide-field, high-cadence sensitive surveys span electromagnetic spectrum from radio all way up to TeV, as well high-energy neutrino window. Among numerous classes transients, γ –ray bursts (GRBs) have direct links with most hot topics that be addressed, such strong gravity regime, relativistic shocks, particle acceleration...
Supernova remnants (SNRs) represent a powerful laboratory to study the Cosmic-Ray acceleration processes at shocks, and their relation properties of circumstellar medium. With aim studying high-frequency radio emission investigating energy distribution accelerated electrons magnetic field conditions, we performed single-dish observations large complex Cygnus Loop SNR from 7.0 24.8 GHz with Medicina Sardinia Radio Telescope, focusing on northern filament (NGC 6992) southern shell. Both...
We report the earliest-ever detection of optical polarization from a GRB forward shock (GRB 141220A), measured $129.5-204.3\,$s after burst using multi-colour RINGO3 polarimeter on 2-m fully autonomous robotic Liverpool Telescope. The temporal decay gradient light curves $86\,$s to $\sim 2200\,$s post-burst is typical classical shocks with $\alpha = 1.091 \pm 0.008$. low $P_{BV} 2.8_{- 1.6} ^{+ 2.0} \, \%$ (2$\sigma$) at mean time 168\,$s compatible being induced by host galaxy dust ($A_{V,...
We present a new solar radio imaging system implemented through the upgrade of large single-dish telescopes Italian National Institute for Astrophysics (INAF), not originally conceived observations. During development and early science phase project (2018-2020), we obtained about 170 maps entire disk in 18-26 GHz band, filling observational gap field at these frequencies. These images have typical resolutions 0.7-2 arcmin range brightness temperature sensitivity <10 K. Accurate calibration...
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Context. Gamma-ray burst (GRB) afterglows originate from the interaction between relativistic ejecta and surrounding medium. Consequently, their properties depend on several aspects: radiation mechanisms, shock micro-physics, circumburst environment, structure geometry of jet. While standard afterglow model accounts for overall spectral temporal evolution a number GRBs, its validity limits emerge when data set is particularly rich constraining, especially in radio band. Aims. We aimed to...
The Sun is an extraordinary workbench, from which several fundamental astronomical parameters can be measured with high precision. Among these parameters, the solar radius $R_{\odot}$ plays important role in aspects, such as evolutionary models. Despite efforts obtaining accurate measurements of $R_{\odot}$, subject still debated and are puzzling and/or lacking many frequency ranges. We aimed to determine mean, equatorial, polar radii ($R_c$, $R_{eq}$, $R_{pol}$) range 18.1 - 26.1 GHz....
One of the most important objectives solar physics is physical understanding atmosphere, structure which also described in terms density (N) and temperature (T) distributions atmospheric matter. Several multi-frequency analyses show that characteristics these are still debated, especially for outer coronal emission. We aim to constrain T N atmosphere through observations centimetric radio domain. employ single-dish from two INAF telescopes at K-band frequencies (18 - 26 GHz). investigate...
Context. One of the most important objectives solar physics is to gain a physical understanding atmosphere, whose structure can also be described in terms density ( N ) and temperature T distributions atmospheric matter. Several multi-frequency analyses have shown that characteristics these are still under debate, especially for outer coronal emission. Aims. We aim constrain atmosphere through observations centimetric radio domain. employed single-dish from two INAF telescopes at K -band...
megameter).
Solaris is a scientific and technological project aimed at the development of smart Solar monitoring system high radio frequencies, based on single-dish imaging techniques. It combines implementation dedicated interchangeable high-frequency receivers existing small telescope systems (1.5/2.6m class) available in our laboratories Antarctica, to be adapted for observations. can perform observations nearly 20h/day during Antarctic summer with optimal sky opacity, it will only facility offering...
Abstract Broad-line type Ic Supernovae (BL-Ic SNe) are characterized by high ejecta velocity (≳10 4 km s −1 ) and sometimes associated with the relativistic jets typical of long duration (≳2 s) Gamma-Ray Bursts. The reason why a small fraction BL-Ic SNe harbor is not known. Here we present deep X-ray radio observations SN 2014ad extending from 13 to 930 days post explosion. was detected at either frequency has no observational evidence GRB counterpart. proximity ( d ∼ 26 Mpc) enables very...