Please use this identifier to cite or link to this item:
http://hdl.handle.net/20.500.12386/32652
Title: | Magnetic field strength in cosmic web filaments | Authors: | CARRETTI, ETTORE VACCA, VALENTINA O'Sullivan, S. P. Heald, G. H. Horellou, C. Röttgering, H. J. A. Scaife, A. M. M. Shimwell, T. W. Shulevski, A. Stuardi, C. Vernstrom, T. |
Issue Date: | 2022 | Journal: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | Number: | 512 | Issue: | 1 | First Page: | 945 | Abstract: | We used the rotation measure (RM) catalogue derived from the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS DR2) at 144 MHz to measure the evolution with redshift of the extragalactic RM (RRM: Residual RM) and the polarization fraction (p) of sources in low-density environments. We also measured the same at 1.4 GHz by cross-matching with the NRAO VLA Sky Survey RM catalogue. We find that RRM versus redshift is flat at 144 MHz, but, once redshift-corrected, it shows evolution at high significance. Also, p evolves with redshift with a decrement by a factor of ~8 at z ~ 2. Comparing the 144-MHz and 1.4-GHz data, we find that the observed RRM and p are most likely to have an origin local to the source at 1.4 GHz, while a cosmic web filament origin is favoured at 144 MHz. If we attribute the entire signal to filaments, we infer a mean rest-frame RRM per filament of RRM$_{\rm 0,f} = 0.71 \pm 0.07 \, \, \rm rad\, m^{-2}$ and a magnetic field per filament of B<SUB>f</SUB> = 32 ± 3 nG. This is in agreement with estimates obtained with a complementary method based on synchrotron emission stacking, and with cosmological simulations if primordial magnetic fields are amplified by astrophysical source field seeding. The measurement of an RRM<SUB>0, f</SUB> supports the presence of diffuse baryonic gas in filaments. We also estimated a conservative upper limit of the filament magnetic turbulence of $\sigma _{\rm RRM_{\rm 0,f}} =0.039 \pm 0.001 \, \, \rm rad\, m^{-2}$, concluding that the ordered magnetic field component dominates in filaments. | URI: | http://hdl.handle.net/20.500.12386/32652 | URL: | http://arxiv.org/abs/2202.04607v1 https://academic.oup.com/mnras/article-abstract/512/1/945/6528375?redirectedFrom=fulltext |
ISSN: | 0035-8711 | DOI: | 10.1093/mnras/stac384 | Bibcode ADS: | 2022MNRAS.512..945C | Fulltext: | open |
Appears in Collections: | 1.01 Articoli in rivista |
Files in This Item:
File | Description | Size | Format | |
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2202.04607.pdf | postprint | 1.09 MB | Adobe PDF | View/Open |
stac384.pdf | PDF editoriale | 2.22 MB | Adobe PDF | View/Open |
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