Dec 11 – 15, 2023
Tsung-Dao Lee Institute
Asia/Shanghai timezone

Testing fundamental physics with PTA and astrometry measurements of stochastic gravitational wave background

Dec 15, 2023, 10:10 AM
Hall # 10

Hall # 10

Contributed talk in mini symposium GW Astrophysics


Meng-Xiang Lin (University of Pennsylvania)


The detection of gravitational waves from the LIGO/Virgo collaboration provides an excellent probe for the fundamental physics of gravity, and the recent pulsar timing arrays (PTA) detections of stochastic gravitational wave background (SGWB) open a new window due to their different frequency sensitivity (nHz band). We explore the possibility of testing gravity using PTA signals by studying the impact of modified gravity on the angular correlation of the overlap reduction function (in GR it is approximated by the Hellings-Downs curve). We find a distinct signature, a shift in the minimal angle of the angular distribution, and demonstrate that this shift is quantitatively sensitive to any change in the phase velocity.
On the other hand, astrometry also holds the potential to detect SGWB by precisely measuring the stellar positions. We explore the feasibility of using astrometry for the identification of parity-violating signals which is not possible in PTA measurements. This is achieved by defining and quantifying a non-vanishing EB correlation function within astrometric correlation functions, and investigating how one might estimate the detectability of such signals.
(The talk is mainly based on and

Primary author

Meng-Xiang Lin (University of Pennsylvania)


Prof. Mark Trodden (University of Pennsylvania) Dr Qiuyue Liang (Kavli IPMU) Prof. Sam Wong (City University of Hong Kong)

Presentation materials