Browsing by Author "Bersier, D."
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- ItemA NEW POPULATION OF ULTRA-LONG DURATION GAMMA-RAY BURSTS(IOP PUBLISHING LTD, 2014) Levan, A. J.; Tanvir, N. R.; Starling, R. L. C.; Wiersema, K.; Page, K. L.; Perley, D. A.; Schulze, S.; Wynn, G. A.; Chornock, R.; Hjorth, J.; Cenko, S. B.; Fruchter, A. S.; O'Brien, P. T.; Brown, G. C.; Tunnicliffe, R. L.; Malesani, D.; Jakobsson, P.; Watson, D.; Berger, E.; Bersier, D.; Cobb, B. E.; Covino, S.; Cucchiara, A.; de Ugarte Postigo, A.; Fox, D. B.; Gal Yam, A.; Goldoni, P.; Gorosabel, J.; Kaper, L.; Kruehler, T.; Karjalainen, R.; Osborne, J. P.; Pian, E.; Sanchez Ramirez, R.; Schmidt, B.; Skillen, I.; Tagliaferri, G.; Thoene, C.; Vaduvescu, O.; Wijers, R. A. M. J.; Zauderer, B. A.We present comprehensive multiwavelength observations of three gamma-ray bursts (GRBs) with durations of several thousand seconds. We demonstrate that these events are extragalactic transients; in particular, we resolve the long-standing conundrum of the distance of GRB 101225A (the "Christmas-day burst"), finding it to have a redshift z = 0.847 and showing that two apparently similar events (GRB 111209A and GRB 121027A) lie at z = 0.677 and z = 1.773, respectively. The systems show extremely unusual X-ray and optical light curves, very different from classical GRBs, with long-lasting, highly variable X-ray emission and optical light curves that exhibit little correlation with the behavior seen in the X-ray. Their host galaxies are faint, compact, and highly star-forming dwarf galaxies, typical of "blue compact galaxies." We propose that these bursts are the prototypes of a hitherto largely unrecognized population of ultra-long GRBs, which while observationally difficult to detect may be astrophysically relatively common. The long durations may naturally be explained by the engine-driven explosions of stars of much larger radii than normally considered for GRB progenitors, which are thought to have compact Wolf-Rayet progenitor stars. However, we cannot unambiguously identify supernova signatures within their light curves or spectra. We also consider the alternative possibility that they arise from the tidal disruption of stars by massive black holes and conclude that the associated timescales are only consistent with the disruption of compact stars (e. g., white dwarfs) by black holes of relatively low mass (<10(5) M-circle dot).
- ItemGRB 120422A/SN 2012bz : Bridging the gap between low- and high-luminosity gamma-ray bursts(2014) Schulze, S.; Malesani, D.; Cucchiara, A.; Tanvir, N.; Kruhler, T.; De Ugarte Postigo, A.; Leloudas, G.; Lyman, J.; Bersier, D.; Bauer, Franz Erik
- ItemPESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects(2015) Smartt, S. J.; Valenti, S.; Fraser, M.; Inserra, C.; Young, D. R.; Sullivan, M.; Bauer, Franz Erik; Clocchiatti, Alejandro; Romero Cañizales, Cristina; Schulze, S.; Pastorello, A.; Benetti, S.; Gal-Yam, A.; Knapic, C.; Molinaro, M.; Smareglia, R.; Smith, K. W.; Taubenberger, S.; Yaron, O.; Anderson, J. P.; Ashall, C.; Balland, C.; Baltay, C.; Barbarino, C.; Baumont, S.; Bersier, D.; Blagorodnova, N.; Bongard, S.; Botticella, M. T.; Bufano, F.; Bulla, M.; Cappellaro, E.; Campbell, H.; Cellier-Holzem, F.; Chen, T. W.; Childress, M. J.; Contreras, C.; Dall’Ora, M.; Danziger, J.; de Jaeger, T.; De Cia, A.; Della Valle, M.; Dennefeld, M.; Elias Rosa, N.; Elman, N.; Feindt, U.; Fleury, M.; Gall, E.; González Gaitan, S.; Galbany, L.; Morales Garoffolo, A.; Greggio, L.; Guillou, L. L.; Hachinger, S.; Hadjiyska, E.; Hage, P. E.; Hillebrandt, W.; Hodgkin, S.; Hsiao, E. Y.; James, P. A.; Jerkstrand, A.; Kangas, T.; Kankare, E.; Kotak, R.; Kromer, M.; Kuncarayakti, H.; Leloudas, G.; Lundqvist, P.; Lyman, J. D.; Hook, I. M.; Maguire, K.; Manulis, I.; Margheim, S. J.; Mattila, S.; Maund, J. R.; Mazzali, P. A.; McCrum, M.; McKinnon, R.; Moreno Raya, M. E.; Nicholl, M.; Nugent, P.; Pain, R.; Pignata, Giuliano; Phillips, M. M.; Polshaw, J.; Pumo, M. L.; Rabinowitz, D.; Reilly, E.; Scalzo, R.; Schmidt, B.; Sim, S.; Sollerman, J.; Taddia, F.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Turatto, M.; Walker, E.; Walton, N. A.; Wyrzykowski, L.; Yuan, F.; Zampieri, L.
- ItemThe ASAS-SN bright supernova catalogue - I. 2013-2014(OXFORD UNIV PRESS, 2017) Holoien, T. W. S.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Prieto, J. L.; Brimacombe, J.; Bersier, D.; Bishop, D. W.; Dong, Subo; Brown, J. S.; Danilet, A. B.; Simonian, G. V.; Basu, U.; Beacom, J. F.; Falco, E.; Pojmanski, G.; Skowron, D. M.; Wozniak, P. R.; Avila, C. G.; Conseil, E.; Contreras, C.; Cruz, I.; Fernandez, J. M.; Koff, R. A.; Guo, Zhen; Herczeg, G. J.; Hissong, J.; Hsiao, E. Y.; Jose, J.; Kiyota, S.; Long, Feng; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Wiethoff, W. S.We present basic statistics for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) during its first year-and-a-half of operations, spanning 2013 and 2014. We also present the same information for all other bright (mV <= 17), spectroscopically confirmed supernovae discovered from 2014 May 1 through the end of 2014, providing a comparison to the ASAS-SN sample starting from the point where ASAS-SN became operational in both hemispheres. In addition, we present collected redshifts and near-UV through IR magnitudes, where available, for all host galaxies of the bright supernovae in both samples. This work represents a comprehensive catalogue of bright supernovae and their hosts from multiple professional and amateur sources, allowing for population studies that were not previously possible because the all-sky emphasis of ASAS-SN redresses many previously existing biases. In particular, ASAS-SN systematically finds bright supernovae closer to the centres of host galaxies than either other professional surveys or amateurs, a remarkable result given ASAS-SN's poorer angular resolution. This is the first of a series of yearly papers on bright supernovae and their hosts that will be released by the ASAS-SN team.
- ItemThe optical rebrightening of GRB100814A: an interplay of forward and reverse shocks?(OXFORD UNIV PRESS, 2015) De Pasquale, Massimiliano; Kuin, N. P. M.; Oates, S.; Schulze, S.; Cano, Z.; Guidorzi, C.; Beardmore, A.; Evans, P. A.; Uhm, Z. L.; Zhang, B.; Page, M.; Kobayashi, S.; Castro Tirado, A.; Gorosabel, J.; Sakamoto, T.; Fatkhullin, T.; Pandey, S. B.; Im, M.; Chandra, P.; Frail, D.; Gao, H.; Kopac, D.; Jeon, Y.; Akerlof, C.; Huang, K. Y.; Pak, S.; Park, W. K.; Gomboc, A.; Melandri, A.; Zane, S.; Mundell, C. G.; Saxton, C. J.; Holland, S. T.; Virgili, F.; Urata, Y.; Steele, I.; Bersier, D.; Tanvir, N.; Sokolov, V. V.; Moskvitin, A. S.We present a wide data set of gamma-ray, X-ray, UV/Opt/IR (UVOIR), and radio observations of the Swift GRB100814A. At the end of the slow decline phase of the X-ray and optical afterglow, this burst shows a sudden and prominent rebrightening in the optical band only, followed by a fast decay in both bands. The optical rebrightening also shows chromatic evolution. Such a puzzling behaviour cannot be explained by a single component model. We discuss other possible interpretations, and we find that a model that incorporates a long-lived reverse shock and forward shock fits the temporal and spectral properties of GRB100814 the best.