title: A repeating fast radio burst.
abstract: Fast radio bursts are millisecond-duration astronomical radio pulses of unknown physical origin that appear to come from extragalactic distances. Previous follow-up observations have failed to find additional bursts at the same dispersion measure (that is, the integrated column density of free electrons between source and telescope) and sky position as the original detections. The apparent non-repeating nature of these bursts has led to the suggestion that they originate in cataclysmic events. Here we report observations of ten additional bursts from the direction of the fast radio burst FRB 121102. These bursts have dispersion measures and sky positions consistent with the original burst. This unambiguously identifies FRB 121102 as repeating and demonstrates that its source survives the energetic events that cause the bursts. Additionally, the bursts from FRB 121102 show a wide range of spectral shapes that appear to be predominantly intrinsic to the source and which vary on timescales of minutes or less. Although there may be multiple physical origins for the population of fast radio bursts, these repeat bursts with high dispersion measure and variable spectra specifically seen from the direction of FRB 121102 support an origin in a young, highly magnetized, extragalactic neutron star.
authors.affiliation: Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, B-53121 Bonn, Germany.
authors.forename: L G
authors.initials: LG
authors.lastname: Spitler
authors.affiliation: Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Scholz
authors.affiliation: ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands.|Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: J W T
authors.initials: JW
authors.lastname: Hessels
authors.affiliation: Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA.
authors.forename: S
authors.initials: S
authors.lastname: Bogdanov
authors.affiliation: Department of Astronomy and Space Sciences, Cornell University, Ithaca, New York 14853, USA.|Cornell Center for Advanced Computing, Cornell University, Ithaca, New York 14853, USA.
authors.forename: A
authors.initials: A
authors.lastname: Brazier
authors.affiliation: Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA.|Square Kilometre Array South Africa, Pinelands, 7405, South Africa.
authors.forename: F
authors.initials: F
authors.lastname: Camilo
authors.affiliation: Department of Astronomy and Space Sciences, Cornell University, Ithaca, New York 14853, USA.
authors.forename: S
authors.initials: S
authors.lastname: Chatterjee
authors.affiliation: Department of Astronomy and Space Sciences, Cornell University, Ithaca, New York 14853, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Cordes
authors.affiliation: Department of Physics and Astronomy, Franklin and Marshall College, Lancaster, Pennsylvania 17604-3003, USA.
authors.forename: F
authors.initials: F
authors.lastname: Crawford
authors.affiliation: National Research Council, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington DC 20375, USA.
authors.forename: J
authors.initials: J
authors.lastname: Deneva
authors.affiliation: Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.
authors.forename: R D
authors.initials: RD
authors.lastname: Ferdman
authors.affiliation: Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, B-53121 Bonn, Germany.
authors.forename: P C C
authors.initials: PC
authors.lastname: Freire
authors.affiliation: Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.
authors.forename: V M
authors.initials: VM
authors.lastname: Kaspi
authors.affiliation: Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, B-53121 Bonn, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Lazarus
authors.affiliation: National Radio Astronomy Observatory, PO Box 2, Green Bank, West Virginia 24944, USA.|Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA.
authors.forename: R
authors.initials: R
authors.lastname: Lynch
authors.affiliation: Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.
authors.forename: E C
authors.initials: EC
authors.lastname: Madsen
authors.affiliation: Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: McLaughlin
authors.affiliation: Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Patel
authors.affiliation: National Radio Astronomy Observatory, Charlottesville, West Virginia 22903, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Ransom
authors.affiliation: Arecibo Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612, USA.
authors.forename: A
authors.initials: A
authors.lastname: Seymour
authors.affiliation: Department of Physics and McGill Space Institute, McGill University, 3600 University Street, Montreal, Quebec H3A 2T8, Canada.|Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: I H
authors.initials: IH
authors.lastname: Stairs
authors.affiliation: Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.
authors.forename: B W
authors.initials: BW
authors.lastname: Stappers
authors.affiliation: ASTRON, Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands.|Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van Leeuwen
authors.affiliation: Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, B-53121 Bonn, Germany.
authors.forename: W W
authors.initials: WW
authors.lastname: Zhu