期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 512, 期 1, 页码 945-959出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stac384
关键词
magnetic fields; polarization; methods: statistical; intergalactic medium; large-scale structure of the Universe
资金
- INAF mainstream project 'Galaxy Clusters Science with LOFAR' [1.05.01.86.05]
- Alan Turing Institute [EP/V030302/1]
- MIUR grant FARE 'SMS'. LOFAR
- CNRS-INSU, France
- Observatoire de Paris, France
- Universite d'Orleans, France
- BMBF, Germany
- MIWF-NRW, Germany
- MPG, Germany
- Science Foundation Ireland (SFI), Ireland
- Department of Business, Enterprise and Innovation (DBEI), Ireland
- NWO, The Netherlands
- The Science and Technology Facilities Council, UK
- Ministry of Science and Higher Education, Poland
- The Istituto Nazionale di Astrofisica (INAF), Italy
- SURF Cooperative (e-infra) [180169]
- LOFAR e-infra group
- Gauss Centre for Supercomputing e.V. through the John von Neumann Institute for Computing (NIC) [CHTB00]
- STFC [ST/P000096/1]
- Physics Department of Turin University (Consorzio Interuniversitario per la Fisica Spaziale) at the C3S Supercomputing Centre, Italy
Using the RM catalogue, we measured the evolution of RRM and p with redshift at different frequencies. RRM at 144 MHz is flat with redshift, but shows significant evolution when redshift-corrected. Comparing the data at different frequencies, 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 favored at 144 MHz.
We used the rotation measure (RM) catalogue derived from the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS DR2) at 144MHz 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 similar to 8 at z similar to 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 RRM0,f = 0.71 +/- 0.07 rad m(-2) and a magnetic field per filament of B-f = 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 RRM0, f supports the presence of diffuse baryonic gas in filaments. We also estimated a conservative upper limit of the filament magnetic turbulence of sigma(RRM0,f) = 0.039 +/- 0.001 rad m(-2), concluding that the ordered magnetic field component dominates in filaments.
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