Description
Chair: Yousuke Itoh (NITEP, Osaka Metropolitan University)
Pulsar timing array is an experiment to detect gravitational waves with a frequency of nanohertz by accurate long-term observation of pulsars. The pulsar timing array has various systematic errors such as dispersion delays caused by interstellar plasma and uncertainty in the position and motion of solar system objects, which inhibit detection of gravitational wave signals. Recently, there have...
We explore the possibility that the new results from the pulsar timing array (PTA) observations could come from the secondary gravitational wave sourced by curvature perturbations generated by a first-order phase transition during the inflation. Based on the results of a field-theoretic lattice simulation of the phase transition process, we show that the gravitational wave signal generated...
Pulsar timing arrays (PTAs) provide a way to detect gravitational waves (GWs) at nanohertz frequencies. To ensure the detection of GWs, observational data must exhibit the Hellings-Downs angular correlation. It is also known that PTAs can probe ultralight dark matter. In this talk, we consider possible contamination of the Hellings-Downs angular correlation by the ultralight dark matter. We...
The recent pulsar timing array (PTA) data show evidence of the stochastic gravitational wave (GW) background around the nanohertz frequency range. With the power-law fit, the data, particularly those of the NANOGrav, favor the spectral index of the cosmological strength of the GWs, Omega_GW(f), around 2. We discuss explanations of the PTA data by GWs induced by curvature perturbations. In...
