# Limits on anisotropy in the nanohertz stochastic gravitational-wave background

Abstract : The paucity of observed supermassive black hole binaries (SMBHBs) may imply that the gravitational wave background (GWB) from this population is anisotropic, rendering existing analyses sub-optimal. We present the first constraints on the angular distribution of a nanohertz stochastic GWB from circular, inspiral-driven SMBHBs using the $2015$ European Pulsar Timing Array data [Desvignes et al. (in prep.)]. Our analysis of the GWB in the $\sim 2 - 90$ nHz band shows consistency with isotropy, with the strain amplitude in $l>0$ spherical harmonic multipoles $\lesssim 40\%$ of the monopole value. We expect that these more general techniques will become standard tools to probe the angular distribution of source populations.
Keywords :
Document type :
Journal articles
Domain :

Cited literature [39 references]

https://hal-insu.archives-ouvertes.fr/insu-01265421
Contributor : Nathalie Rouchon <>
Submitted on : Monday, October 24, 2016 - 3:49:12 PM
Last modification on : Wednesday, October 21, 2020 - 4:32:15 PM

### File

PhysRevLett.115.pdf
Publisher files allowed on an open archive

### Citation

S. R. Taylor, C. M. F. Mingarelli, J. R. Gair, A. Sesana, Gilles Theureau, et al.. Limits on anisotropy in the nanohertz stochastic gravitational-wave background. Physical Review Letters, American Physical Society, 2015, 115 (4), pp.041101. ⟨10.1103/PhysRevLett.115.041101⟩. ⟨insu-01265421⟩

Record views