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Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes
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- I. Andreoni, K. Ackley, J. Cooke, A. Acharyya, J. R. Allison, G. E. Anderson, M. C. B. Ashley, D. Baade, M. Bailes, K. Bannister, A. Beardsley, M. S. Bessell, F. Bian, P. A. Bland, M. Boer, T. Booler, A. Brandeker, I. S. Brown, D. A. H. Buckley, S.-W. Chang, D. M. Coward, S. Crawford, H. Crisp, B. Crosse, A. Cucchiara, M. Cupák, J. S. de Gois, A. Deller, H. A. R. Devillepoix, D. Dobie, E. Elmer, D. Emrich, W. Farah, T. J. Farrell, T. Franzen, B. M. Gaensler, D. K. Galloway, B. Gendre, T. Giblin, A. Goobar, J. Green, P. J. Hancock, B. A. D. Hartig, E. J. Howell, L. Horsley, A. Hotan, R. M. Howie, L. Hu, Y. Hu, C. W. James, S. Johnston, M. Johnston-Hollitt, D. L. Kaplan, M. Kasliwal, E. F. Keane, D. Kenney, A. Klotz, R. Lau, R. Laugier, E. Lenc, X. Li, E. Liang, C. Lidman, L. C. Luvaul, C. Lynch, B. Ma, D. Macpherson, J. Mao, D. E. McClelland, C. McCully, A. Möller, M. F. Morales, D. Morris, T. Murphy, K. Noysena, C. A. Onken, N. B. Orange, S. Osłowski, D. Pallot, J. Paxman, S. B. Potter, T. Pritchard, W. Raja, R. Ridden-Harper, E. Romero-Colmenero, E. M. Sadler, E. K. Sansom, R. A. Scalzo, B. P. Schmidt, S. M. Scott, N. Seghouani, Z. Shang, R. M. Shannon, L. Shao, M. M. Shara, R. Sharp, M. Sokolowski, J. Sollerman, J. Staff, K. Steele, T. Sun, N. B. Suntzeff, C. Tao, S. Tingay, M. C. Towner, P. Thierry, C. Trott, B. E. Tucker, P. Väisänen, V. Venkatraman Krishnan, M. Walker, L. Wang, X. Wang, R. Wayth, M. Whiting, A. Williams, T. Williams, C. Wolf, C. Wu, X. Wu, J. Yang, X. Yuan, H. Zhang, J. Zhou, H. Zovaro
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- Journal:
- Publications of the Astronomical Society of Australia / Volume 34 / 2017
- Published online by Cambridge University Press:
- 20 December 2017, e069
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The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
Contributors
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- By Eric Adler, Anoushka Afonso, Dean B. Andropoulos, Adel Bassily-Marcus, Yaakov Beilin, Elliott Bennett-Guerrero, Howard H. Bernstein, Marc J. Bloom, David Bronheim, Albert T. Cheung, Samuel DeMaria, Deborah Dubensky, James B. Eisenkraft, Jonathan Elmer, Liza J. Enriquez, Jonathan Epstein, Jeffrey M. Feldman, Gregory W. Fischer, Brigid Flynn, Jennifer A. Frontera, Richard S. Gist, Glenn P. Gravlee, Christina L. Jeng, Ronald A. Kahn, Jenny Kam, Mukul Kapoor, Jung Kim, Roopa Kohli-Seth, Aaron F. Kopman, Tuula S. O. Kurki, Andrew B. Leibowitz, Matthew Levin, Adam I. Levine, Michael S. Lewis, Justin Lipper, Martin London, Michael L. McGarvey, Alexander J. C. Mittnacht, Timothy Mooney, Diana Mungall, Yasuharu Okuda, Peter J. Papadakos, Jayashree Raikhelkar, Lakshmi V. Ramanathan, David L. Reich, Meg A. Rosenblatt, Corey Scurlock, Tamas Seres, Linda Shore-Lesserson, Marc E. Stone, Daniel M. Thys, Judit Tolnai, David Wax, Nathaen Weitzel
- David L. Reich, Mount Sinai School of Medicine, New York
- Edited by Ronald A. Kahn, Mount Sinai School of Medicine, New York, Alexander J. C. Mittnacht, Mount Sinai School of Medicine, New York, Andrew B. Leibowitz, Mount Sinai School of Medicine, New York, Marc E. Stone, Mount Sinai School of Medicine, New York, James B. Eisenkraft, Mount Sinai School of Medicine, New York
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- Book:
- Monitoring in Anesthesia and Perioperative Care
- Published online:
- 05 July 2011
- Print publication:
- 08 August 2011, pp vii-ix
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Monte Carlo Modelling of Electrophotographic Dark Discharge
- S. J. Elmer, J. M. Marshall, R. A. C. M. M. Van Swaaij, J. Bezemer, A. R. Hepburn
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- Journal:
- MRS Online Proceedings Library Archive / Volume 336 / 1994
- Published online by Cambridge University Press:
- 16 February 2011, 195
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- 1994
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In an electrophotographic experiment, surface voltage is measured for a-Si1-xCx:H films of different thicknesses. It is observed that the thickness normalised dark decay rate (TNDDR) at longer times is smaller for thicker than for thinner specimens. This phenomenon has also been reported for other materials. In order to get a better understanding of the dark discharge process, the monte Carlo technique is used to model electrophotographic dark discharge in materials of which a-Si1-xCx:H is typical. The present study considers every carrier within the model after each increment of a short time step. This then allows bimolecular effects and the presence of space charge to be accounted for.
The study concentrates on two different discharge mechanisms and the effects they have on the TNDDR for varying specimen thicknesses. For the first of these, a negative charge is deposited on the surface of the sample and drifts through the bulk under the influence of the local internal field (Surface Injection model). In the second, electron/hole pairs are generated within the bulk with both carriers being mobile through the specimen (Bulk Generation model). The subsequent surface decay is due to the recombination of bulk generated holes and trapped surface electrons. Results from these models are compared with those found experimentally.