title: The magnetic field and turbulence of the cosmic web measured using a brilliant fast radio burst.
abstract: Fast radio bursts (FRBs) are millisecond-duration events thought to originate beyond the Milky Way galaxy. Uncertainty surrounding the burst sources, and their propagation through intervening plasma, has limited their use as cosmological probes. We report on a mildly dispersed (dispersion measure 266.5 ± 0.1 parsecs per cubic centimeter), exceptionally intense (120 ± 30 janskys), linearly polarized, scintillating burst (FRB 150807) that we directly localize to 9 square arc minutes. On the basis of a low Faraday rotation (12.0 ± 0.7 radians per square meter), we infer negligible magnetization in the circum-burst plasma and constrain the net magnetization of the cosmic web along this sightline to <21 nanogauss, parallel to the line-of-sight. The burst scintillation suggests weak turbulence in the ionized intergalactic medium.
authors.affiliation: Cahill Center for Astronomy and Astrophysics, MC249-17, California Institute of Technology, Pasadena, CA 91125, USA. vikram@caltech.edu ryan.shannon@csiro.au.
authors.forename: V
authors.initials: V
authors.lastname: Ravi
authors.affiliation: Commonwealth Scientific and Industrial Research Organization (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, NSW 1710, Australia. vikram@caltech.edu ryan.shannon@csiro.au.|International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102, Australia.
authors.forename: R M
authors.initials: RM
authors.lastname: Shannon
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Post Office Box 218, Hawthorn, VIC 3122, Australia.|ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia.
authors.forename: M
authors.initials: M
authors.lastname: Bailes
authors.affiliation: Commonwealth Scientific and Industrial Research Organization (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, NSW 1710, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Bannister
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Post Office Box 218, Hawthorn, VIC 3122, Australia.|ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia.
authors.forename: S
authors.initials: S
authors.lastname: Bhandari
authors.affiliation: International Centre for Radio Astronomy Research, Curtin University, Bentley, WA 6102, Australia.|ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia.
authors.forename: N D R
authors.initials: ND
authors.lastname: Bhat
authors.affiliation: National Radio Astronomy Observatory, Array Operations Center, Post Office Box 0, Socorro, NM 87801-0387, USA.
authors.forename: S
authors.initials: S
authors.lastname: Burke-Spolaor
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Post Office Box 218, Hawthorn, VIC 3122, Australia.|ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia.|Research School of Astronomy and Astrophysics, Australian National University, ACT 2611, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Caleb
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Post Office Box 218, Hawthorn, VIC 3122, Australia.|ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia.
authors.forename: C
authors.initials: C
authors.lastname: Flynn
authors.affiliation: Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Post Office Box 218, Hawthorn, VIC 3122, Australia.|ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia.
authors.forename: A
authors.initials: A
authors.lastname: Jameson
authors.affiliation: Commonwealth Scientific and Industrial Research Organization (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, NSW 1710, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Johnston
authors.affiliation: Square Kilometer Array (SKA) Organisation, Jodrell Bank Observatory, SK11 9DL, UK.
authors.forename: E F
authors.initials: EF
authors.lastname: Keane
authors.affiliation: Commonwealth Scientific and Industrial Research Organization (CSIRO) Astronomy and Space Science, Australia Telescope National Facility, Post Office Box 76, Epping, NSW 1710, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Kerr
authors.affiliation: Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Tiburzi
authors.affiliation: Manly Astrophysics, 3/22 Cliff Street, Manly NSW 2095, Australia.
authors.forename: A V
authors.initials: AV
authors.lastname: Tuntsov
authors.affiliation: Cahill Center for Astronomy and Astrophysics, MC249-17, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: H K
authors.initials: HK
authors.lastname: Vedantham