Progetti di ricerca

We are on the verge of the next big breakthrough in gravitational wave (GW) astronomy: namely the detection of a nano-Hz GW signal with Pulsar Timing Arrays (PTAs). Within the next few years nano-Hz GWs will be established as a completely… Leggi tutto new window on our Universe, unlocking an unprecedented opportunity to unveil its secrets. The signal is anticipated to come from a cosmic population of supermassive black hole binaries (SMBHBs), which are a fundamental, yet observationally missing, piece in the process of structure formation and galaxy evolution. However, alternative Early Universe origins, including backgrounds arising from inflation or phase transitions, cannot be dismissed a priori. To exploit the scientific breakthrough potential of this new window we need an innovative, robust framework to build our way forward in uncharted territory. A framework that allows us to establish the nature of the nano-Hz GW signal and understand its implications for astrophysics and cosmology. PINGU is this framework; it is a concerted multimessenger project for connecting the GW and electromagnetic (EM) Universe in a novel way. On the one hand, it will leverage on the 15-year long expertise of the PI in PTA observations, data analysis and signal characterization to pin down the properties of the nano-Hz GW signal and characterize its features. On the other hand, it will exploit the most powerful all sky survey and state of the art galaxy formation models to construct a live nano-Hz GW map of our Universe and match it with the upcoming results of PTA observations. This will allow us to exploit the full potential of the nano-Hz GW sky, including: i) establishing the origin of the GW signal and probe its astrophysical nature, ii) gain unprecedented insights into the formation and evolution of SMBHBs and their role in galaxy formation, iii) identify SMBHBs and map their distribution in the Universe, iv) enable, for the first time, multimessenger astronomy in the nano-Hz GW band

Massive black hole binaries (MBHBs) are the most extreme, fascinating yet elusive astrophysical objects in the Universe. Establishing observationally their existence will be a milestone for contemporary astronomy, providing a fundamental missing piece in the puzzle of galaxy formation, piercing through the… Leggi tutto (hydro)dynamical physical processes shaping dense galactic nuclei from parsec scales down to the event horizon, and probing gravity in extreme conditions. We can both see and listen to MBHBs. Remarkably, besides arguably being among the brightest variable objects shining in the Cosmos, MBHBs are also the loudest gravitational wave (GW) sources in the Universe. As such, we shall take advantage of both the type of messengers – photons and gravitons – they are sending to us, which can now be probed by all-sky time-domain surveys and radio pulsar timing arrays (PTAs) respectively. B MASSIVE leverages on a unique comprehensive approach combining theoretical astrophysics, radio and gravitationalwave astronomy and time-domain surveys, with state of the art data analysis techniques to: i) observationally prove the existence of MBHBs, ii) understand and constrain their astrophysics and dynamics, iii) enable and bring closer in time the direct detection of GWs with PTA. As European PTA (EPTA) executive committee member and former I International PTA (IPTA) chair, I am a driving force in the development of pulsar timing science world-wide, and the project will build on the profound knowledge, broad vision and wide collaboration network that established me as a world leader in the field of MBHB and GW astrophysics. B MASSIVE is extremely timely; a pulsar timing data set of unprecedented quality is being assembled by EPTA/IPTA, and Time-Domain astronomy surveys are at their dawn. In the long term, B MASSIVE will be a fundamental milestone establishing European leadership in the cutting-edge field of MBHB astrophysics in the era of LSST, SKA and LISA.