title: A strong ultraviolet pulse from a newborn type Ia supernova.
abstract: Type Ia supernovae are destructive explosions of carbon-oxygen white dwarfs. Although they are used empirically to measure cosmological distances, the nature of their progenitors remains mysterious. One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion. Here we report observations with the Swift Space Telescope of strong but declining ultraviolet emission from a type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star, and therefore provides evidence that some type Ia supernovae arise from the single degenerate channel.
authors.affiliation: Astronomy Department, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.affiliation: 1] Astronomy Department, California Institute of Technology, Pasadena, California 91125, USA [2] Caltech Optical Observatories, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Kulkarni
authors.affiliation: 1] Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, California 93117, USA [2] Department of Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: D Andrew
authors.initials: DA
authors.lastname: Howell
authors.affiliation: Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Avishay
authors.initials: A
authors.lastname: Gal-Yam
authors.affiliation: Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, California 91101, USA.
authors.forename: Mansi M
authors.initials: MM
authors.lastname: Kasliwal
authors.affiliation: 1] Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, California 93117, USA [2] Department of Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: Stefano
authors.initials: S
authors.lastname: Valenti
authors.affiliation: The Oskar Klein Centre, Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Johansson
authors.affiliation: The Oskar Klein Centre, Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: R
authors.initials: R
authors.lastname: Amanullah
authors.affiliation: The Oskar Klein Centre, Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Goobar
authors.affiliation: The Oskar Klein Centre, Department of Astronomy, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Sollerman
authors.affiliation: The Oskar Klein Centre, Department of Astronomy, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: F
authors.initials: F
authors.lastname: Taddia
authors.affiliation: Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Assaf
authors.initials: A
authors.lastname: Horesh
authors.affiliation: Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Ilan
authors.initials: I
authors.lastname: Sagiv
authors.affiliation: Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, Maryland 20771, USA.
authors.forename: S Bradley
authors.initials: SB
authors.lastname: Cenko
authors.affiliation: 1] Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] Astronomy Department, University of California, Berkeley, 501 Campbell Hall, Berkeley, California 94720, USA.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Nugent
authors.affiliation: 1] Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, California 93117, USA [2] Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA.
authors.forename: Iair
authors.initials: I
authors.lastname: Arcavi
authors.affiliation: Spitzer Science Center, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Jason
authors.initials: J
authors.lastname: Surace
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: P R
authors.initials: PR
authors.lastname: Woźniak
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: Daniela I
authors.initials: DI
authors.lastname: Moody
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
authors.forename: Umaa D
authors.initials: UD
authors.lastname: Rebbapragada
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Bue
authors.affiliation: Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, Maryland 20771, USA.
authors.forename: Neil
authors.initials: N
authors.lastname: Gehrels