Probing the anisotropic distribution of baryon matter in the Universe using fast radio bursts

Abstract

We propose that fast radio bursts (FRBs) can be used as the probes to constrain the possible anisotropic distribution of baryon matter in the Universe. Monte Carlo simulations show that, 400 (800) FRBs are enough to detect the anisotropy at 95% (99%) confidence level, if the dipole amplitude is at the order of magnitude 0.01. However, much more FRBs are required to tightly constrain the dipole direction. Even 1000 FRBs are far from enough to constrain the dipole direction within angular uncertainty ∆θ < 40 • at 95% confidence level. The uncertainty on the dispersion measure of host galaxy does not significantly affect the results. If the dipole amplitude is in the level of 0.001, however, 1000 FRBs are not enough to correctly detect the anisotropic signal.

Model-independent constraints on the baryon fraction in the IGM from fast radio bursts and supernovae data

“…If one can identify the host galaxy of the bursts, we can use the dispersion measure (DM) versus redshift (DM − z) relation of these events as a tool to study the underlying cosmology. In fact, FRBs have been used to constrain cosmological parameters [11,12], such as the Hubble parameter H(z) [13] and Hubble constant H 0 [14,15], to probe the anisotropic distribution of baryon matter in Universe [16], as well as to constrain the fraction of baryon mass in the intergalactic medium (IGM) [17,18,19].…”