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Title: Intergalactic Medium Rotation Measure of Primordial Magnetic Fields
Abstract The Faraday rotation effect, quantified by the rotation measure (RM), is a powerful probe of the large-scale magnetization of the Universe—tracing magnetic fields not only on galaxy and galaxy cluster scales but also in the intergalactic medium (IGM; referred to as RMIGM). The redshift dependence of the latter has extensively been explored with observations. It has also been shown that this relation can help to distinguish between different large-scale magnetization scenarios. We study the evolution of this RMIGMfor different primordial magnetogenesis scenarios to search for the imprints of primordial magnetic fields (PMFs; magnetic fields originating in the early Universe) on the redshift-dependence of RMIGM. We use cosmological magnetohydrodynamic simulations for evolving PMFs during large-scale structure formation, coupled with the light-cone analysis to produce a realistic statistical sample of mock RMIGMimages. We study the predicted behavior for the cosmic evolution of RMIGMfor different correlation lengths of PMFs, and provide fitting functions for their dependence on redshifts. We compare these mock RM trends with the recent analysis of the the LOw-Frequency ARray RM Grid and find that large-scale-correlated PMFs should have (comoving) strengths ≲0.75 nG, if they originated during inflation with the scale-invariant spectrum and (comoving) correlation length of ∼19h−1cMpc or ≲30 nG if they originated during phase-transition epochs with the comoving correlation length of ∼1h−1cMpc. Our findings agree with previous observations and confirm the results of semi-analytical studies, showing that upper limits on the PMF strength decrease as their coherence scales increase.  more » « less
Award ID(s):
2307698 2408411
PAR ID:
10636395
Author(s) / Creator(s):
; ; ; ; ; ; ;
Publisher / Repository:
AAS
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
977
Issue:
1
ISSN:
0004-637X
Page Range / eLocation ID:
128
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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