Dependence of Residual Rotation Measure (RRM) on Intervening MgII Absorbers at Cosmic Distances

TL;DR

This study examines how intervening MgII absorption systems influence the residual rotation measure (RRM) of quasars, revealing that such absorbers contribute to increased RRM variability at 21cm wavelength, consistent with previous findings at 6cm.

Contribution

It provides the first large-sample statistical analysis showing the impact of MgII absorbers on RRM at 21cm wavelength, extending prior work at shorter wavelengths.

Findings

Intervening MgII absorbers increase RRM variability by about 8 Rad/m^2.

Significant correlation between MgII absorbers and enhanced RRM at 21cm.

Results support the role of intervening absorbers in extragalactic magnetic field studies.

Abstract

We investigate the dependence of residual rotation measure (RRM) on intervening absorption systems at cosmic distances by using a large sample of 539 SDSS quasars in conjunction with the available rotation measure catalog at around 21cm wavelength. We found an excess extragalactic contribution in standard deviation of observed RRM of about 8.11+/-4.83 Rad/m^2 in our sample with intervening MgII absorber as compare to the sample without MgII absorber. Our results suggest that intervening absorbers could contribute to the enhancement of RRM at around 21cm wavelength, as was found earlier for RM measurements at around 6cm wavelength.