In this talk we will review the main observational and theoretical evidences that point toward a magnetars as FRB progenitors.
The galactic magnetar SGR 1935+2154 provided on April 28, 2020 the first observational evidence for a connection between magnetars and FRBs. Since then this magnetar has attracted much interest and several observational campaigns and detailed studies of its behavior have been performed.
This has also been facilitated by the fact that SGR 1935+2154 has been the most active magnetars in the...
During this presentation I will present recent advancements on the study of fast radio bursts (FRBs) – short, energetic radio flashes of extragalactic origin, with typical durations of a millisecond – through low frequency observations conducted with the Northern Cross radio telescope. In particular, I will show how long-term radio monitoring of a sample of nearby galaxies can help investigate...
he radio emission from magnetars is poorly understood and characterized observationally, in particular for what concerns single pulses and sporadic events.
The interest in it was boosted by the recent detection of an extremely bright ms radio signal from the Galactic magnetar SGR 1935+2154, which occurred almost simultaneously with a typical magnetar short burst of X-rays.
As of now, this...
The first observational evidence linking magnetars and Fast Radio Bursts (FRBs) was the detection of simultaneous radio and X-ray bursts from the Galactic magnetar SGR 1935+2154 in 2020.
We analysed over 25 hours of observations from the Large-Sized Telescope prototype (LST-1) of the Cherenkov Telescope Array Observatory (CTAO) during periods of high-energy activity in 2021 and 2022,...
Over 15 years after their discovery, the nature of fast radio burst (FRB) sources still eludes our understanding. To date their bright, coherent radio emission has no detected counterparts outside of the radio band, with the exception of the FRB-like flares emitted by the galactic magnetar SGR 1935+215. These lended support, among the countless proposed interpretations, to the idea that FRB...
Fast Radio Bursts (FRBs) have, since their first detection, ranked among the most puzzling events in the sky owing to the extreme energies involved and the presence of both repeating and non-repeating sources: 15 years and thousands of bursts later, their emission mechanism still eludes us. I will present a new unified model for FRBs as magnetospheric events from neutron stars which naturally...
INAF has always been involved in the development of activities for astronomy outreach and education. The purpose is to exploit innovative teaching approaches to foster the development of scientific and critical thinking, which are fundamental skills in our society.
“Hunting for FRBs” is one of the activities developed so far that represents these aspects. This educational workshop aims to...
The first Italian workshop on FRBs aims to bring together the national scientific community interested in these enigmatic phenomena, fostering collaborations and new research projects. An essential aspect of the initiative’s success is effective communication, which helps engage both the scientific community and the broader public. This contribution will explore targeted communication...
Emission outside the radio band is predicted for most models trying to explain the FRB phenomenon. Its nature, however, is still to be determined, with the exception of the possible example provided by the Galactic FRB20200428A, where X-ray emission was observed simultaneously with the radio emission, with an energy ratio E_X/E_radio = 10^5.
I will review the targeted attempts to search for...
The first Chinese X-ray mission, Insight Hard X-ray Modulation Telescope (Insight-HXMT), carries on board three collimator-based instruments, which altogether cover the range 1-250 keV. In addition, the High-Energy (HE) instrument works as an open-sky monitor in the 0.2-3 MeV. In this talk I report two main contributions of Insight-HXMT: a) thanks to the unique combination of large effective...
Up to date, there is only one FRB counterpart observed in hard X-rays. Bursts from a peculiar magnetar SGR 1935+2154 associated with FRB 200428, detected by INTEGRAL. In this work, an extensive search for hard X-ray bursts below the automatic INTEGRAL ISGRI-IBIS detection threshold that would be spatially and temporally coincident with the activity of recently active FRB repeaters has been...
Repeating FRBs are ideal targets for multi-wavelength observational campaigns aiming at potential counterparts. We are monitoring FRB 20220912A, one of the most active repeaters, using the fast optical photon counters Aqueye+ and Iqueye at the Asiago Observatory. We are trying to characterize foreground/background events by analyzing archival Aqueye+ data taken on other fields. To this purpose...
High-time-resolution detectors are playing a crucial role in advancing our understanding of fast transient events enabling precise measurements of their properties. SiFAP2, a state-of-the-art high-speed optical photometer permanently mounted at the 3.6m INAF Telescopio Nazionale Galileo (TNG) paved the way for significant breakthroughs in optical observations, especially on neutron stars. This...
The AGILE space mission, with its unique features (two coaligned imaging X- and gamma-ray detectors, a non-imaging calorimeter, and
the observing capability to cover about 80% if the sky in 7 minutes), participated to all the recent campaign searches for electromagnetic
(e.m.) counterparts of multi messenger events (gravitational waves and neutrinos), but also to high-energy counterparts...
We report on a comprehensive search for X-ray and Gamma-ray counterparts to a selected sample of repeating FRBs using AGILE data. Focusing on events with an excess dispersion measure below 300 pc cm⁻³, our high-resolution analysis with the AGILE MiniCalorimiter (MCAL) did not reveal any significant X-ray emission, enabling us to set robust upper limits on the flux above 400 keV within a...
Giant pulses (GPs) are very energetic and impulsive phenomena, with flux densities up to few MJy and pulse widths from ~100 ns to ~100 µs, as observed from the Crab pulsar. The GPs observed from the Crab pulsar can be used to study the energy distribution and their dynamic spectra can address the emission mechanisms of neutron stars. Some fast radio bursts (FRBs) models involve neutron stars...
The physical origin of Fast Radio Bursts (FRBs) is still unknown. Many models consider magnetars as possible FRB sources, supported by the observational association of FRBs with the galactic magnetar SGR 1935+2154. Magnetars are also thought to be the source of the power of a fraction of Gamma Ray Bursts (GRBs), opening the possibility that the two extreme phenomena have a common...
Neutron star (NS) mergers, detected via gravitational wave (GW) signals by LIGO and Virgo, create extreme magnetized environments, providing optimal conditions for coherent radio emission observable as a fast radio burst (FRB). The temporal and spatial coincidences between GW events and FRBs offer a unique opportunity to directly identify FRB progenitors, test models of magnetar formation, and...
One of the most surprising Gamma Ray Burst (GRB) features discovered with the Swift X-ray telescope (XRT) is a plateau phase in the early X-ray afterglow lightcurves. These plateaus are observed in the majority of long GRBs, while their incidence in short GRBs is still uncertain due to their fainter X-ray afterglow luminosity with respect to long GRBs. An accurate estimate of the fraction of...
Fast Radio Bursts (FRBs) are a recently discovered class of GHz-band astrophysical transients with an unknown origin. Exploring their potential gamma-ray and gravitational wave (GW) counterparts is crucial for constraining their emission mechanisms. We present a search for GW signals from FRBs, focusing on the Galactic magnetar SGR 1935+2154, using the GEO600 detector, setting the strictest...
INAF manages three single-dish radio telescopes: SRT, Medicina, Noto. The science of pulsars and Fast Radio Bursts constitutes key projects in radio astronomy. SRT already plays a key role in various projects, such as the EPTA, which uses radio pulsar data to search for gravitational waves. Currently-available instrumentation at SRT severely limits its possible scientific return. At Medicina...
The discovery of fast radio bursts (FRBs) was a serendipitous process, much like the detection of the first pulsar by S. J. Bell. Since the first FRB was identified in 2007, both hardware and software technologies for detecting these enigmatic transients have advanced dramatically, enabling the discovery of increasingly exotic events. In this talk, I will review the current state of FRB...
A number of models predict the existence of multiwavelength (MWL) counterparts of Fast Radio Bursts (FRBs) in the form of an afterglow or an impulsive event. An optical detection would provide critical information on the nature of the progenitor and would greatly enhance our understanding of the FRB phenomenon. Suitable instrumentation and/or strategies are required for sensitive searches of...
The long unexplored fast optical sky is now accessible thanks to new large ground-based telescopes and new generation instruments. Studying it may lead to new discoveries, but it is also challenging due to optical pollution.
In this talk, I will present our preliminary results obtained from an automated search and characterisation of mysterious Fast (millisecond) Optical Bursts (FOBs) in over...
Magnetar giant flares (MGFs) are the most extreme transient events observed from these magnetically-powered neutron stars. They consist of an initial peak lasting fractions of a second during which the luminosity in the X and soft $\gamma$ band can reach up to 10$^{47}$ erg s$^{-1}$, followed by a decaying X-ray tail lasting hundreds of seconds and showing periodic modulation.
The periodic...
Deep investigation of the environment where the bursts occur is the most promising way to shed light on these mysterious phenomena. Observations of a handful of events indicated different progenitor channels, yielding to distinct location, local environment and host galaxy properties. The recent discovery of a persistent radio source associated with FRB 20201124A and 20240114A supports the...
A handful of repeating Fast Radio Bursts (FRBs) have been found to be spatially associated with a compact persistent radio source (PRS). Observational evidence suggests that the continuum emission of PRSs originates from a nebula embedding either a magnetar or a binary system of compact objects. Therefore, PRSs are crucial targets to investigate the progenitors of FRBs and their formation...
One key aspect required to understand the origin of FRBs is to know the type of environment they are emitted in. Thus, not only the host galaxy of an FRB is of importance, but also the precise location within that host need to be determined to solve the FRB-puzzle. Such accurate measurements are only possible with Very Long Baseline Interferometry. I will review the cases of FRBs localised...
Although FRBs are frequent events, the precise localization has only been achieved in a limited number of cases. However, this number has doubled in the past year. In this talk, we will present key properties of a sample of galaxies hosting these events, compiled from existing publications. Over 100 FRB host galaxies have been identified so far, with redshifts measured for most of them. The...
The number of FRB host galaxies is constantly increasing thanks to the precise localization of new interferometric facilities. With the aim of keeping track of and making the observed and derived FRB parameters accessible to the entire community, we are implementing a new catalogue. It will be fed by user data and made publicly accessible both programmatically and via a web interface.
The...
Because of their extragalactic origin, FRBs can serve as very unique probes to explore our Universe. With nearly 150 localised FRBs with redshifts up to z=1.35, by use of the Macquart relation alone it is possible to study different cosmological aspects and even address some open issues in cosmology such as the missing baryon problem or the Hubble tension.
In my talk I will give a general...
The Northern Cross is a T-shaped radio interferometer located at the Medicina station, near Bologna, operating at 408 MHz. It has been undergoing a significant refurbishment/restoration over the last few years, allowing observations of fast radio bursts (FRBs, a project named "Northern Cross FRB project"). In this talk I will review the status of the project (past and current observing...
A short report on the progress of the CHORD project (British Columbia - Canada).
