Martedì 11 luglio alle 14.30 nell'Aula Maxwell del Plesso di Fisica, Michele Vallisneri (Jet Propulsion Laboratory) terrà un seminario sulla evidenza di un fondo stocastico di onde gravitazionali recentemente annunciata dalla collaborazione NANOGRAV.The North American Nanohertz Observatory for Gravitational Waves 15 Year Data Set: Evidence for a Stochastic Gravitational-Wave BackgroundMichele Vallisneri, Jet Propulsion LaboratoryFor the past 15 years the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has been constructing and monitoring a pulsar timing array to detect and study gravitational waves at nanohertz frequencies. By tracking the exact arrival times of radio pulses from 68 pulsars in the Milky Way over 15 years, NANOGrav has now found evidence for a stochastic background of gravitational waves, with the distinctive correlated timing deviations predicted by general relativity. The spectral characteristics of the background agree with expectations for a population of inspiraling (but not yet coalescing) supermassive black hole binaries, with masses of approximately 100 million to 10 billion Solar masses. However, alternative cosmological hypotheses cannot be ruled out. This talk presents the NANOGrav 15-year data set and the results of the search for gravitational waves, and discusses future prospects.Organizzatore: prof. Massimo Pietroni Links utili per chiarire il contesto e la rilevanza scientifica: An Enormous Gravity ‘Hum’ Moves Through the Universe TheNANOGrav15-yearDataSet:EvidenceforaGravitational-WaveBackground
