Conveners
Parallel - Transients, Pulsars, GW
- Andrea Possenti (INAF)
- Marcello Giroletti (Istituto Nazionale di Astrofisica (INAF))
Parallel - Transients, Pulsars, GW
- Marcello Giroletti (Istituto Nazionale di Astrofisica (INAF))
- Andrea Possenti (INAF)
Parallel - Transients, Pulsars, GW
- Marcello Giroletti (Istituto Nazionale di Astrofisica (INAF))
- Andrea Possenti (INAF)
Parallel - Transients, Pulsars, GW
- Andrea Possenti (INAF)
- Marcello Giroletti (Istituto Nazionale di Astrofisica (INAF))
The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a very-low frequency (~ nano-Hertz) common signal with correlation properties compatible with a gravitational wave (GW) signal. In this talk, I will first describe the methodology and outcome of the pulsar timing and noise analysis applied to the EPTA and InPTA combined data. Then I will...
I will present the astrophysical interpretations of the recently published evidence for a nanohertz gravitational wave background, as detected by pulsar timing arrays. I will discuss the future of low-frequency gravitational wave astronomy with PTAs and the upcoming contribution of SKA precursors to those datasets.
Although the recent evidence presented by PTAs is that for a stochastic gravitational wave background (GWB) which was most likely produced by the superimposition of a number of GW signals, simulations of the merger history of supermassive black hole binaries (SMBHBs) suggest a narrow possibility of the detection of some of the most massive or fortunately located individual continuous GW (CGW)...
Pulsar Timing Array (PTA) experiments use well-timed pulsars to probe the gravitational universe at frequencies down to a few nanohertz. This band is populated by gravitational waves emitted by binary systems of supermassive black holes (SMBHBs). The most common signal sought by PTA experiments is a stochastic gravitational wave background, generated by the superposition of hundreds of...
One of the top science goals for the SKA is the study of pulsars, and in particular the use of pulsar timing arrays (PTAs) for the detection of low-frequency gravitational waves (GWs). In 2023, PTA collaborations around the world have revealed evidence for a background of low-frequency GWs, possibly from supermassive black hole binaries or cosmological sources. A higher significance is however...
Pulsar observations have been an important target for MeerKAT having two Large Survey Projects (MeerTIME and TRAPUM) dedicated to them. This has led to the discovery of more than 200 new pulsars within globular clusters, unidentified Fermi sources, the Magellanic clouds and the Galactic disk. Furthermore, the timing of the known pulsars has led to numerous measurements of neutron star masses,...
It is believed that about $10^8-10^9$ old neutron stars and a comparable number of stellar mass black holes are present in the Milky Way. While isolated neutron stars can be detected as rotation-powered pulsars if young and energetic enough, or, less frequently, as thermal X-ray emitters, isolated black holes have up to now escaped firm detection. Our knowledge of stellar mass black holes...
The discovery of transitional millisecond pulsars demonstrated that slight variations in the mass accretion rate can induce swings between a rotation-powered radio pulsar state and an accretion-powered X-ray pulsar regime. However, ten years after the first transitions seen, these pulsars turned out to be relatively rare. Transiently accreting millisecond pulsars are expected to turn on as...
Some massive stars end their lives with a catastrophic explosion which leaves behind a spinning, stellar mass black hole or a highly magnetised neutron star. Regardless of the nature of the remnant, this central engine launches two jets of ionised matter which eventually interact with the circum-burst medium through external shocks, producing the so called Gamma-Ray Burst (GRB) afterglow,...
Next generation GRB space missions like The Transient High-Energy Sky and Early Universe Surveyor (THESEUS), led by INAF and under study by ESA, aim at exploiting Gamma-Ray Bursts for investigating the early Universe and at providing a substantial advancement of multi-messenger and time-domain astrophysics. THESEUS will address main open issues in cosmology such as, e.g., star formation rate...
We present the results of a campaign of observations, aimed at disclosing the origin of a persistent and extended radio emission embedding FRB 20201124A as found in Piro et al. 2021. New high resolution VLA observations show the presence on a flat-spectrum compact source coincident with the position of the FRB, that dominates the radio emission above 10 GHz. Spectral-imaging obtained with the...
One of the most intriguing problems in modern time-domain radio astronomy, which will be a key scientific question to address for the SKA observatory, is understanding the nature and origin of fast radio bursts (FRBs). FRBs are bright radio transients primarily originating from sources outside our galaxy, and, to date, they have only been observed in the radio band.
On April 28, 2020, the...
