TY  - JOUR
AU  - Xue, Xiaorui
AU  - Pan, Zhen
AU  - Dai, Liang
TI  - Non-Gaussian statistics of nanohertz stochastic gravitational waves
JO  - Physical review / D
VL  - 111
IS  - 4
SN  - 2470-0010
CY  - Ridge, NY
PB  - American Physical Society
M1  - PUBDB-2025-04362
M1  - arXiv:2409.19516
M1  - DESY-24-137
SP  - 043022
PY  - 2025
N1  - 14 pages including references, 8 figures. Accepted by Phys. Rev. D
AB  - Multiple pulsar timing arrays (PTAs) have recently reported evidence for nHz stochastic gravitational wave background (SGWB), stimulating intensive discussions about its physical origin. In principle, the sources may be either supermassive black hole binaries (SMBHBs) or processes in the early Universe. One key difference between the two lies in the statistics of the SGWB frequency power spectrum. In particular, the often assumed Gaussian random SGWB does not accurately describe the distribution of the collective SMBHB emission. This work presents a semianalytical framework for calculating the non-Gaussian statistics of SGWB power expected from SMBHBs. We find that (a) wave interference between individual SMBHBs with indistinguishable observed frequencies and (b) the Poisson fluctuation of the source numbers, together shape the non-Gaussian statistics. Implementing the non-Gaussian statistics developed in this work, we investigate the sensitivity of current and future PTA datasets in distinguishing the origin of the SGWB through non-Gaussian information. Additionally, we find an interesting approximation of the non-Gaussian statistics, which has implications for accurately and practically treating non-Gaussianity in PTA Bayesian analyses.
KW  - gravitational radiation, stochastic (INSPIRE)
KW  - black hole, binary (INSPIRE)
KW  - gravitational radiation, background (INSPIRE)
KW  - statistics (INSPIRE)
KW  - non-Gaussianity (INSPIRE)
KW  - power spectrum (INSPIRE)
KW  - fluctuation (INSPIRE)
KW  - sensitivity (INSPIRE)
KW  - interference (INSPIRE)
KW  - Poisson (INSPIRE)
KW  - Bayesian (INSPIRE)
KW  - pulsar (INSPIRE)
KW  - collective (INSPIRE)
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1103/PhysRevD.111.043022
UR  - https://bib-pubdb1.desy.de/record/639242
ER  -