The talk will summarise main observational results obtained by the current network of gravitational wave detectors, including the ongoing O4 run which started May 2023. First half of O4 - O4a - ended January 2024, providing 81 new high-confidence gravitational wave candidates. I will also discuss challenges and outlook related to searches for transient signals emitted by tight binaries...
The direct detection of gravitational waves from highly energetic collisions of compact binary systems comprising black holes and/or neutron stars has inaugurated
an exciting new era in astrophysical science. In recent years, searches have been designed to look for other types of gravitational radiation, including the much fainter long-duration, persistent emission known as continuous waves....
The gravitational wave background (GWB) is a superposition of weak, independent and unresolved gravitational wave (GW) sources. It can be sourced by both astrophysical and cosmological sources, among which we find unresolved compact binary coalescences, supernovae, first order cosmological phase transitions and cosmic strings. Since the beginning of its observational runs, the LIGO-Virgo-KAGRA...
Pulsar Timing Arrays (PTAs) exploit the extreme rotational stability of pulsars to chase the direct detection of nanoHertz-frequency gravitational waves (GWs), hence expanding the accessible windows of the GW spectrum.
In 2023, the European together with the Indian PTA (EPTA, InPTA), the North American PTA and the Australian PTA presented three series of articles reporting the first...
Solving for exact and analytical solutions in general relativity to extract gravitational waves is a challenging task and for most of the known astrophysical systems it is not realised. In addition to this the understanding of gravitational waves transient universe is in early stages and hence searching for all possible transient events in all sky direction and with gravitational waveform of...
We present a case study on archival open GW data to test new methodological improvements in targeted searches for gravitational-wave transients associated with core-collapse supernovae.
The study involves core-collapse supernovae optically observed within 30 Mpc during the third observing run of Advanced LIGO and Advanced Virgo. We report the detection efficiency and the distance range for...
The LVK O4 observing run resumed in April. In this talk we will discuss the main public results so far, along with the perspectives for the upgrades of the detectors and the next observation periods.
The Einstein Telescope (ET) is the planned third-generation gravitational wave (GW) observatory in Europe, expected to start operating in the late 2030s. It will be an underground and cryogenic GW detector, aiming to push the observation horizon to the primordial high-redshift universe, with huge impact on multimessenger astronomy, cosmology, and fundamental physics.
In this talk I will give...
Quantum Noise (QN) represents one of the main limitations to the Gravitational Wave (GW) interferometersโ sensitivity in all the frequency bandwidth (10Hz - 10kHz) [1, 2, 3]. During the run O3, the implementation of frequency-independent squeezing (FIS) demonstrated powerful quantum shot noise reduction in the high-frequency region above 50 Hz in Virgo and LIGO [4, 5]. Nevertheless, FIS at...
The Laser Interferometer Space Antenna (LISA) will be a space-borne gravitational wave (GW) detector to be launched in the next decade. Central to LISA data analysis is time-delay interferometry (TDI), a numerical procedure which drastically reduces otherwise overwhelming laser frequency noise. LISA data analysis is usually performed on sets of TDI variables, e.g. Michelson variables (X, Y, Z)...
Gravitational waves have opened a new window on the cosmos and revolutionized our view of astrophysical phenomena. Current ground-based interferometers such as Advanced LIGO, Virgo and KAGRA are currently the most sensitive detectors and form a worldwide network capable of rapid detection and localization of gravitational wave signals of coalescence of compact binary systems. Nearly real-time...
The first half of LIGO-Virgo-KAGRA's (LVK) fourth observing run (O4) concluded earlier this year. During the eight-month observation period, the number of gravitational-wave candidates has almost doubled compared to the total number of events reported from the first three observing runs combined (O1, O2, and O3) and includes the gravitational-wave event GW230529; a gravitational-wave signal...
This study investigates the influence of a spectrum of gravitational wave signals from coalescing binaries on the search for continuous waves (CWs) in the Einstein Telescope and during Virgo O5.
With the forthcoming upgrades to current detectors and the advent of third-generation detectors, an increased number of inspiral compact object cycles in the frequency band will be detected, leading...
A biaxial or triaxial neutron star rotating about a non-principal axis of inertia emits a dual harmonic gravitational wave. i.e., gravitational wave at its rotational frequency and twice its rotational frequency. Those signals undergo modulations due to Earth's rotation and orbital motion, which create frequency shifts and side bands in the signal when they reach the gravitational wave...
This work discusses the implementation of LongFT: a procedure to enable the exact computation of very long Fourier transforms without the need of expensive supercomputers with TeraBytes of RAM.
Our software tool will let independent researchers and/or small research groups worldwide to perform uncompromised spectral analyses, even when low in budget or computing resources.
LongFT has its...
The impressive computational cost required to probe a vast parameter space forces blind searches for Continuous Gravitational Waves (CW) to undertake a semi-coherent approach. On top of that, the sensitivity to CW depends on the coherent segment's length and obviously on the total observation time. Hence, searches have to be supported by follow-up pipelines where this baseline is gradually...
Compact binary mergers mark the final stage of a complex journey that begins with massive star binaries. Within the isolated channel, binaries undergo intricate processes, including mass transfer and tidal interactions, ultimately giving rise to neutron stars or black holes. Notably, chemically-homogeneous evolution, prevalent in metal-poor binary systems, significantly influences this process...
Since the groundbreaking first detection of gravitational waves (GWs) from merging black holes and neutron stars in 2015, current ground-based GW detectors have identified around 100 such events. These discoveries have unveiled the mass and spin distributions of stellar-mass black holes, provided new insights into the behavior of superdense matter, and offered an independent measurement of the...
The first three observing runs of the Advanced LIGO-Virgo-KAGRA detector network have led to the detection of about 90 compact binary coalescences, mergers of binaries of black holes or neutron stars. These observations have given us access to an otherwise uncharted regime of dynamical strong-field gravity. In this talk we briefly review the many tests of general relativity performed with...
Gravitational wave signals from compact binary mergers are excellent cosmological probes due to their ability to act as standard sirens: objects with measured luminosity distance which is independent of the cosmic distance ladder. This opens up new ways of measuring cosmological parameters, which is particularly relevant in the era of the so-called "Hubble tension". However, in order for this...
Dark matter could compose ~80% of all matter in the universe, and yet it is completely invisible to us. Despite decades of experiments designed to detect dark matter, and numerous models for potential dark matter particles, no concrete evidence has been put forward to support the existence of beyond standard-model physics. Because of this, it is worth asking whether approaching the detection...
