03/14 2023 Seminar
- Title题目 Gravitational waves and fundamental physics with Pulsar Timing Arrays
- Speaker报告人 陈偲源 (北京大学科维理天文与天体物理研究所)
- Date日期 2023年03月14日 14:30
- Venue地点 线下: 6620 ITP South Building 线上: 腾讯会议：100-934-042 https://meeting.tencent.com/dm/QL9yaBYExXCZ
Pulsar Timing Arrays (PTAs) search for nHz gravitational waves by timing the radio signals from a network of stable millisecond pulsars and looking for a spatially correlated common signal in the data set. We expect to find a gravitational wave background (GWB) first, followed by possible individual sources. PTAs have reported the finding of a spectrally similar but spatially uncorrelated signal in various data sets, namely North American Nanohertz Observatory for Gravitational waves (NANOGrav), Australian Parkes PTA, European PTA, together with the Indian PTA they form the International PTA. We hope to deepen collaboration with Chinese and South African PTA colleagues.
I will present results from the different PTAs on the search for a GWB. All PTAs report consistent results of a common signal with a nominal amplitude of 2-3e-15, but no characteristic spatial correlation required for a GWB. This putative signal has been tested against both cosmological and astrophysical sources for a GWB and helped to put constraints for various theories. We are working in the four PTA collaborations to collect and analyze the most recent data sets in a coordinated process, including the supervision of an external Detection Committee under the guidance of the IPTA. We hope to have exciting results to present by the end of this year. These new data sets will form the basis for the next IPTA DR3 combination in the coming year.
Siyuan Chen received his PhD in Physics and Astronomy from the University of Birmingham in the UK under the supervision of Prof. Alberto Sesana in 2018. From 2018 to 2021, he has worked as a postdoctoral researcher at the Centre national de la recherche scientifique (CNRS) in Orleans, France, in the Laboratory for space and evironmental physics and chemistry (LPC2E). During his studies and reasearch Siyuan Chen has been strongly involved with the European Pulsar Timing Array (EPTA). Other collaborations include the Large European Array for Pulsars (LEAP), North American Nanohertz Observatory for Gravitational waves (NANOGrav) and International Pulsar Timing Array (IPTA). At the end of 2021, he has joined the Kavli Institute for Astronomy and Astrophysics at Peking University as a postdoctoral fellow.