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Evans PA, Cenko SB, Kennea JA, Emery SWK, Kuin NPM, Korobkin O, Wollaeger RT, Fryer CL, Madsen KK, Harrison FA, Xu Y, Nakar E, Hotokezaka K, Lien A, Campana S, Oates SR, Troja E, Breeveld AA, Marshall FE, Barthelmy SD, Beardmore AP, Burrows DN, Cusumano G, D'Aì A, D'Avanzo P, D'Elia V, de Pasquale M, Even WP, Fontes CJ, Forster K, Garcia J, Giommi P, Grefenstette B, Gronwall C, Hartmann DH, Heida M, Hungerford AL, Kasliwal MM, Krimm HA, Levan AJ, Malesani D, Melandri A, Miyasaka H, Nousek JA, O'Brien PT, Osborne JP, Pagani C, Page KL, Palmer DM, Perri M, Pike S, Racusin JL, Rosswog S, Siegel MH, Sakamoto T, Sbarufatti B, Tagliaferri G, Tanvir NR, Tohuvavohu A. Swift and NuSTAR observations of GW170817: Detection of a blue kilonova. Science 2017; 358:1565-1570. [PMID: 29038371 DOI: 10.1126/science.aap9580] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 10/04/2017] [Indexed: 11/02/2022]
Abstract
With the first direct detection of merging black holes in 2015, the era of gravitational wave (GW) astrophysics began. A complete picture of compact object mergers, however, requires the detection of an electromagnetic (EM) counterpart. We report ultraviolet (UV) and x-ray observations by Swift and the Nuclear Spectroscopic Telescope Array of the EM counterpart of the binary neutron star merger GW170817. The bright, rapidly fading UV emission indicates a high mass (≈0.03 solar masses) wind-driven outflow with moderate electron fraction (Ye ≈ 0.27). Combined with the x-ray limits, we favor an observer viewing angle of ≈30° away from the orbital rotation axis, which avoids both obscuration from the heaviest elements in the orbital plane and a direct view of any ultrarelativistic, highly collimated ejecta (a γ-ray burst afterglow).
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Affiliation(s)
- P A Evans
- University of Leicester, X-ray and Observational Astronomy Research Group, Leicester Institute for Space and Earth Observation, Department of Physics and Astronomy, University Road, Leicester LE1 7RH, UK.
| | - S B Cenko
- Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.,Joint Space-Science Institute, University of Maryland, College Park, MD 20742, USA
| | - J A Kennea
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
| | - S W K Emery
- University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking RH5 6NT, UK
| | - N P M Kuin
- University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking RH5 6NT, UK
| | - O Korobkin
- Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - R T Wollaeger
- Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - C L Fryer
- Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - K K Madsen
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - F A Harrison
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Y Xu
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - E Nakar
- The Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - K Hotokezaka
- Center for Computational Astrophysics, Simons Foundation, 162 5th Avenue, New York, NY 10010, USA
| | - A Lien
- Center for Research and Exploration in Space Science and Technology (CRESST) and NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.,Department of Physics, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - S Campana
- Istituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate, Italy
| | - S R Oates
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| | - E Troja
- Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA.,Department of Physics and Astronomy, University of Maryland, College Park, MD 20742-4111, USA
| | - A A Breeveld
- University College London, Mullard Space Science Laboratory, Holmbury St. Mary, Dorking RH5 6NT, UK
| | - F E Marshall
- Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - S D Barthelmy
- Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - A P Beardmore
- University of Leicester, X-ray and Observational Astronomy Research Group, Leicester Institute for Space and Earth Observation, Department of Physics and Astronomy, University Road, Leicester LE1 7RH, UK
| | - D N Burrows
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
| | - G Cusumano
- INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Palermo, via Ugo La Malfa 153, I-90146, Palermo, Italy
| | - A D'Aì
- INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Palermo, via Ugo La Malfa 153, I-90146, Palermo, Italy
| | - P D'Avanzo
- Istituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate, Italy
| | - V D'Elia
- INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone, Italy.,Space Science Data Center-Agenzia Spaziale Italiana (ASI), I-00133 Roma, Italy
| | - M de Pasquale
- Department of Astronomy and Space Sciences, University of Istanbul, Beyzt 34119, Istanbul, Turkey
| | - W P Even
- Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545 USA.,Department of Physical Sciences, Southern Utah University, Cedar City, UT 84720, USA
| | - C J Fontes
- Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - K Forster
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - J Garcia
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - P Giommi
- Space Science Data Center-Agenzia Spaziale Italiana (ASI), I-00133 Roma, Italy
| | - B Grefenstette
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - C Gronwall
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA.,Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
| | - D H Hartmann
- Kinard Lab of Physics, Department of Physics and Astronomy, Clemson University, Clemson, SC 29634-0978, USA
| | - M Heida
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - A L Hungerford
- Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - M M Kasliwal
- Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
| | - H A Krimm
- Universities Space Research Association, 7178 Columbia Gateway Drive, Columbia, MD 21046, USA.,National Science Foundation, 2415 Eisenhower Avenue, Alexandria, VA 22314, USA
| | - A J Levan
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK
| | - D Malesani
- Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø, Denmark
| | - A Melandri
- Istituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate, Italy
| | - H Miyasaka
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - J A Nousek
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
| | - P T O'Brien
- University of Leicester, X-ray and Observational Astronomy Research Group, Leicester Institute for Space and Earth Observation, Department of Physics and Astronomy, University Road, Leicester LE1 7RH, UK
| | - J P Osborne
- University of Leicester, X-ray and Observational Astronomy Research Group, Leicester Institute for Space and Earth Observation, Department of Physics and Astronomy, University Road, Leicester LE1 7RH, UK
| | - C Pagani
- University of Leicester, X-ray and Observational Astronomy Research Group, Leicester Institute for Space and Earth Observation, Department of Physics and Astronomy, University Road, Leicester LE1 7RH, UK
| | - K L Page
- University of Leicester, X-ray and Observational Astronomy Research Group, Leicester Institute for Space and Earth Observation, Department of Physics and Astronomy, University Road, Leicester LE1 7RH, UK
| | - D M Palmer
- Los Alamos National Laboratory, B244, Los Alamos, NM 87545, USA
| | - M Perri
- INAF-Osservatorio Astronomico di Roma, via Frascati 33, I-00040 Monteporzio Catone, Italy.,Space Science Data Center-Agenzia Spaziale Italiana (ASI), I-00133 Roma, Italy
| | - S Pike
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - J L Racusin
- Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
| | - S Rosswog
- The Oskar Klein Centre, Department of Astronomy, AlbaNova, Stockholm University, SE-106 91 Stockholm, Sweden
| | - M H Siegel
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
| | - T Sakamoto
- Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa, 252-5258, Japan
| | - B Sbarufatti
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
| | - G Tagliaferri
- Istituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate, Italy
| | - N R Tanvir
- University of Leicester, X-ray and Observational Astronomy Research Group, Leicester Institute for Space and Earth Observation, Department of Physics and Astronomy, University Road, Leicester LE1 7RH, UK
| | - A Tohuvavohu
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
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2
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Boggs SE, Harrison FA, Miyasaka H, Grefenstette BW, Zoglauer A, Fryer CL, Reynolds SP, Alexander DM, An H, Barret D, Christensen FE, Craig WW, Forster K, Giommi P, Hailey CJ, Hornstrup A, Kitaguchi T, Koglin JE, Madsen KK, Mao PH, Mori K, Perri M, Pivovaroff MJ, Puccetti S, Rana V, Stern D, Westergaard NJ, Zhang WW. 44
Ti gamma-ray emission lines from SN1987A reveal an asymmetric explosion. Science 2015; 348:670-1. [DOI: 10.1126/science.aaa2259] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- S. E. Boggs
- Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA
| | - F. A. Harrison
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
| | - H. Miyasaka
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
| | - B. W. Grefenstette
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
| | - A. Zoglauer
- Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA
| | - C. L. Fryer
- CCS-2, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - S. P. Reynolds
- Physics Department, NC State University, Raleigh, NC 27695, USA
| | - D. M. Alexander
- Department of Physics, Durham University, Durham DH1 3LE, UK
| | - H. An
- Department of Physics, McGill University, Rutherford Physics Building, Montreal, Quebec H3A 2T8, Canada
| | - D. Barret
- Université de Toulouse, UPS-OMP, IRAP, Toulouse, France
- CNRS, Institut de Recherche en Astrophysique et Planétologie, 9 Av. colonel Roche, BP 44346, F-31028 Toulouse Cedex 4, France
| | - F. E. Christensen
- DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark
| | - W. W. Craig
- Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - K. Forster
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
| | - P. Giommi
- Agenzia Spaziale Italiana (ASI) Science Data Center, Via del Politecnico snc I-00133, Roma, Italy
| | - C. J. Hailey
- Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA
| | - A. Hornstrup
- DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark
| | - T. Kitaguchi
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - J. E. Koglin
- Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - K. K. Madsen
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
| | - P. H. Mao
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
| | - K. Mori
- Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA
| | - M. Perri
- Agenzia Spaziale Italiana (ASI) Science Data Center, Via del Politecnico snc I-00133, Roma, Italy
- INAF – Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio, Italy
| | - M. J. Pivovaroff
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - S. Puccetti
- Agenzia Spaziale Italiana (ASI) Science Data Center, Via del Politecnico snc I-00133, Roma, Italy
- INAF – Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio, Italy
| | - V. Rana
- Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
| | - D. Stern
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - N. J. Westergaard
- DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark
| | - W. W. Zhang
- NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
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3
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Walton DJ, Harrison FA, Bachetti M, Barret D, Boggs SE, Christensen FE, Craig WW, Fuerst F, Grefenstette BW, Hailey CJ, Madsen KK, Middleton MJ, Rana V, Roberts TP, Stern D, Sutton AD, Webb N, Zhang W. NUSTARANDXMM-NEWTONOBSERVATIONS OF THE EXTREME ULTRALUMINOUS X-RAY SOURCE NGC 5907 ULX1: A VANISHING ACT. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/799/2/122] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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4
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Walton DJ, Harrison FA, Grefenstette BW, Miller JM, Bachetti M, Barret D, Boggs SE, Christensen FE, Craig WW, Fabian AC, Fuerst F, Hailey CJ, Madsen KK, Parker ML, Ptak A, Rana V, Stern D, Webb N, Zhang WW. BROADBAND X-RAY SPECTRA OF THE ULTRALUMINOUS X-RAY SOURCE HOLMBERG IX X-1 OBSERVED WITHNuSTAR,XMM-NEWTON,ANDSUZAKU. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/0004-637x/793/1/21] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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5
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Wik DR, Hornstrup A, Molendi S, Madejski G, Harrison FA, Zoglauer A, Grefenstette BW, Gastaldello F, Madsen KK, Westergaard NJ, Ferreira DDM, Kitaguchi T, Pedersen K, Boggs SE, Christensen FE, Craig WW, Hailey CJ, Stern D, Zhang WW. NuSTAROBSERVATIONS OF THE BULLET CLUSTER: CONSTRAINTS ON INVERSE COMPTON EMISSION. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/0004-637x/792/1/48] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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6
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Grefenstette BW, Harrison FA, Boggs SE, Reynolds SP, Fryer CL, Madsen KK, Wik DR, Zoglauer A, Ellinger CI, Alexander DM, An H, Barret D, Christensen FE, Craig WW, Forster K, Giommi P, Hailey CJ, Hornstrup A, Kaspi VM, Kitaguchi T, Koglin JE, Mao PH, Miyasaka H, Mori K, Perri M, Pivovaroff MJ, Puccetti S, Rana V, Stern D, Westergaard NJ, Zhang WW. Asymmetries in core-collapse supernovae from maps of radioactive 44Ti in Cassiopeia A. Nature 2014; 506:339-42. [PMID: 24553239 DOI: 10.1038/nature12997] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 12/13/2013] [Indexed: 11/09/2022]
Abstract
Asymmetry is required by most numerical simulations of stellar core-collapse explosions, but the form it takes differs significantly among models. The spatial distribution of radioactive (44)Ti, synthesized in an exploding star near the boundary between material falling back onto the collapsing core and that ejected into the surrounding medium, directly probes the explosion asymmetries. Cassiopeia A is a young, nearby, core-collapse remnant from which (44)Ti emission has previously been detected but not imaged. Asymmetries in the explosion have been indirectly inferred from a high ratio of observed (44)Ti emission to estimated (56)Ni emission, from optical light echoes, and from jet-like features seen in the X-ray and optical ejecta. Here we report spatial maps and spectral properties of the (44)Ti in Cassiopeia A. This may explain the unexpected lack of correlation between the (44)Ti and iron X-ray emission, the latter being visible only in shock-heated material. The observed spatial distribution rules out symmetric explosions even with a high level of convective mixing, as well as highly asymmetric bipolar explosions resulting from a fast-rotating progenitor. Instead, these observations provide strong evidence for the development of low-mode convective instabilities in core-collapse supernovae.
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Affiliation(s)
- B W Grefenstette
- Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA
| | - F A Harrison
- Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA
| | - S E Boggs
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - S P Reynolds
- Physics Department, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - C L Fryer
- CCS-2, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K K Madsen
- Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA
| | - D R Wik
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - A Zoglauer
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - C I Ellinger
- Department of Physics, University of Texas at Arlington, Arlington, Texas 76019, USA
| | - D M Alexander
- Department of Physics, Durham University, Durham DH1 3LE, UK
| | - H An
- Department of Physics, McGill University, Rutherford Physics Building, Montreal, Quebec H3A 2T8, Canada
| | - D Barret
- 1] Université de Toulouse, UPS-OMP, IRAP, 9 Avenue du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France [2] CNRS, Institut de Recherche en Astrophysique et Planétologie, 9 Avenue colonel Roche, BP 44346, F-31028 Toulouse Cedex 4, France
| | - F E Christensen
- DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark
| | - W W Craig
- 1] Space Sciences Laboratory, University of California, Berkeley, California 94720, USA [2] Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - K Forster
- Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA
| | - P Giommi
- Agenzia Spaziale Italiana (ASI) Science Data Center, Via del Politecnico snc, I-00133 Roma, Italy
| | - C J Hailey
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - A Hornstrup
- DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark
| | - V M Kaspi
- Department of Physics, McGill University, Rutherford Physics Building, Montreal, Quebec H3A 2T8, Canada
| | - T Kitaguchi
- RIKEN, Nishina Center, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - J E Koglin
- Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - P H Mao
- Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA
| | - H Miyasaka
- Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA
| | - K Mori
- Columbia Astrophysics Laboratory, Columbia University, New York, New York 10027, USA
| | - M Perri
- 1] Agenzia Spaziale Italiana (ASI) Science Data Center, Via del Politecnico snc, I-00133 Roma, Italy [2] INAF - Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio, Italy
| | - M J Pivovaroff
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S Puccetti
- 1] Agenzia Spaziale Italiana (ASI) Science Data Center, Via del Politecnico snc, I-00133 Roma, Italy [2] INAF - Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio, Italy
| | - V Rana
- Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, California 91125, USA
| | - D Stern
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
| | - N J Westergaard
- DTU Space, National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby, Denmark
| | - W W Zhang
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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7
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Baloković M, Ajello M, Blandford RD, Boggs SE, Borracci F, Chiang J, Christensen FE, Craig WW, Forster K, Furniss A, Fürst F, Ghisellini G, Giebels B, Giommi P, Grefenstette BW, Hailey CJ, Harrison FA, Hayashida M, Humensky B, Inoue Y, Koglin JE, Krawczynski H, Madejski GM, Madsen KK, Meier DL, Nelson T, Ogle P, Paneque D, Perri M, Puccetti S, Reynolds CS, Sbarrato T, Stern D, Tagliaferri G, Urry CM, Wehrle AE, Zhang WW. First Results fromNuSTARObservations of Mkn 421. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20136104013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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8
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Risaliti G, Harrison FA, Madsen KK, Walton DJ, Boggs SE, Christensen FE, Craig WW, Grefenstette BW, Hailey CJ, Nardini E, Stern D, Zhang WW. A rapidly spinning supermassive black hole at the centre of NGC 1365. Nature 2013; 494:449-51. [PMID: 23446416 DOI: 10.1038/nature11938] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 01/16/2013] [Indexed: 11/09/2022]
Abstract
Broad X-ray emission lines from neutral and partially ionized iron observed in active galaxies have been interpreted as fluorescence produced by the reflection of hard X-rays off the inner edge of an accretion disk. In this model, line broadening and distortion result from rapid rotation and relativistic effects near the black hole, the line shape being sensitive to its spin. Alternative models in which the distortions result from absorption by intervening structures provide an equally good description of the data, and there has been no general agreement on which is correct. Recent claims that the black hole (2 × 10(6) solar masses) at the centre of the galaxy NGC 1365 is rotating at close to its maximum possible speed rest on the assumption of relativistic reflection. Here we report X-ray observations of NGC 1365 that reveal the relativistic disk features through broadened Fe-line emission and an associated Compton scattering excess of 10-30 kiloelectronvolts. Using temporal and spectral analyses, we disentangle continuum changes due to time-variable absorption from reflection, which we find arises from a region within 2.5 gravitational radii of the rapidly spinning black hole. Absorption-dominated models that do not include relativistic disk reflection can be ruled out both statistically and on physical grounds.
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Affiliation(s)
- G Risaliti
- INAF-Osservatoria Astrofisico di Arcetri, Largo Enrico Fermi 5, 50125 Firenze, Italy.
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9
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Lehre AC, Rowley NM, Zhou Y, Holmseth S, Guo C, Holen T, Hua R, Laake P, Olofsson AM, Poblete-Naredo I, Rusakov DA, Madsen KK, Clausen RP, Schousboe A, White HS, Danbolt NC. Deletion of the betaine-GABA transporter (BGT1; slc6a12) gene does not affect seizure thresholds of adult mice. Epilepsy Res 2011; 95:70-81. [PMID: 21459558 DOI: 10.1016/j.eplepsyres.2011.02.014] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 02/02/2011] [Accepted: 02/27/2011] [Indexed: 10/18/2022]
Abstract
Gamma-aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian brain. Once released, it is removed from the extracellular space by cellular uptake catalyzed by GABA transporter proteins. Four GABA transporters (GAT1, GAT2, GAT3 and BGT1) have been identified. Inhibition of the GAT1 by the clinically available anti-epileptic drug tiagabine has been an effective strategy for the treatment of some patients with partial seizures. Recently, the investigational drug EF1502, which inhibits both GAT1 and BGT1, was found to exert an anti-convulsant action synergistic to that of tiagabine, supposedly due to inhibition of BGT1. The present study addresses the role of BGT1 in seizure control and the effect of EF1502 by developing and exploring a new mouse line lacking exons 3-5 of the BGT1 (slc6a12) gene. The deletion of this sequence abolishes the expression of BGT1 mRNA. However, homozygous BGT1-deficient mice have normal development and show seizure susceptibility indistinguishable from that in wild-type mice in a variety of seizure threshold models including: corneal kindling, the minimal clonic and minimal tonic extension seizure threshold tests, the 6Hz seizure threshold test, and the i.v. pentylenetetrazol threshold test. We confirm that BGT1 mRNA is present in the brain, but find that the levels are several hundred times lower than those of GAT1 mRNA; possibly explaining the apparent lack of phenotype. In conclusion, the present results do not support a role for BGT1 in the control of seizure susceptibility and cannot provide a mechanistic understanding of the synergism that has been previously reported with tiagabine and EF1502.
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Affiliation(s)
- A C Lehre
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, Blindern, Oslo, Norway
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