ALBERT

Description: We report the early discovery of the optical afterglow of gamma-ray burst (GRB) 140801A in the 137 deg 2 3- error-box of the Fermi Gamma-ray Burst Monitor (GBM). MASTER is the only observatory that automatically reacts to all Fermi alerts. GRB 140801A is one of the few GRBs whose optical counterpart was discovered solely from its GBM localization. The optical afterglow of GRB 140801A was found by MASTER Global Robotic Net 53 s after receiving the alert, making it the fastest optical detection of a GRB from a GBM error-box. Spectroscopy obtained with the 10.4-m Gran Telescopio Canarias and the 6-m Big Telescope Alt-azimuth of the Special Astrophysical Observatory of the Russian Academy of Sciences reveals a redshift of z = 1.32. We performed optical and near-infrared photometry of GRB 140801A using different telescopes with apertures ranging from 0.4 to 10.4 m. GRB 140801A is a typical burst in many ways. The rest-frame bolometric isotropic energy release and peak energy of the burst are $E_\mathrm{iso} = 5.54_{-0.24}^{+0.26} {\times} 10^{52}$  erg and E p, rest ~= 280 keV, respectively, which is consistent with the Amati relation. The absence of a jet break in the optical light curve provides a lower limit on the half-opening angle of the jet = 6 $_{.}^{\circ}$ 1. The observed E peak is consistent with the limit derived from the Ghirlanda relation. The joint Fermi GBM and Konus- Wind analysis show that GRB 140801A could belong to the class of intermediate duration. The rapid detection of the optical counterpart of GRB 140801A is especially important regarding the upcoming experiments with large coordinate error-box areas.

Description: [1]  The observed γ -ray fluence distribution of Terrestrial Gamma-ray Flashes (TGFs) detected by the Fermi Gamma-ray Burst Monitor (GBM) is altered by instrumental effects. We perform corrections for deadtime, pulse pile-up and detection efficiency in a model independent manner. A sample of 106 GBM TGFs is selected to include both TGFs which triggered GBM and weaker TGFs found using an offline search. Detector deadtime and pulse pile-up lower the observed fluence of each TGF and the detection efficiency causes weaker TGFs to have a lower probability of detection than brighter TGFs. Monte Carlo simulations are performed in each case to correct for these effects. The corrected fluence distribution is well fit with a power-law of index α  = –2.20 ± 0.13. This is consistent with previous estimates using other techniques. Neither a high-fluence cut-off nor a low-fluence limit is found. The fluence distribution is also expressed in units of TGF hour –1  km –2 versus photons cm –2 per TGF.

Description: The Gamma-Ray Burst Monitor (GBM) on the Fermi Gamma-Ray Space Telescope (Fermi) detected 50 terrestrial gamma-ray flashes (TGFs) during its first 20 months of operation. The high efficiency and large area of the GBM detectors, combined with their fine timing capabilities and relatively high throughput, allow unprecedented studies of the temporal properties of TGFs. The TGF pulses are observed to have durations as brief as ∼0.05 ms, shorter than previously measured. There is a relatively narrow distribution of pulse durations; the majority of pulses have total durations between 0.10 and 0.40 ms. In some TGF events, risetimes as short as ∼0.01 ms and falltimes as short as ∼0.03 ms are observed. Three of the 50 TGFs presented here have well-separated, double peaks. Perhaps as many as 10 other TGFs show evidence, to varying degrees, of overlapping peaks. Weak emission is seen at the leading or trailing edges of some events. Five of the 50 TGFs are considerably longer than usual; these are believed to be caused by incident electrons transported from a TGF at the geomagnetic conjugate point. TGF temporal properties can be used to discriminate between models of the origin of TGFs and also provide some basic physical properties of the TGF process.

Description: Terrestrial Gamma-ray Flashes (TGFs) are brief pulses of energetic radiation that correlate with thunderstorms and lightning. Most TGFs are observed as gamma-ray pulses; less frequently they can be observed as electrons and positrons that travel along the geomagnetic field line from the source to the detector. In this paper we predict where electron TGFs should be observed by tracing geomagnetic field lines from likely TGF sources and determining the intersections with satellite orbits. TGF source locations are based upon lightning maps by the Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD). Predictions are made both for existing spacecraft with instruments observing TGFs and for other orbits. We compare the predictions to the locations of TGFs that have been observed as electron TGFs. 12 of the 13 known electron TGFs are within the predicted high-rate regions. Based on the predicted location maps of electron TGFs, we find that electron TGFs should sometimes be observed above areas with low lightning activity and that electron TGFs are best observed at low altitudes (below approximately 1000 km).

Description: A cornerstone of Einstein's special relativity is Lorentz invariance-the postulate that all observers measure exactly the same speed of light in vacuum, independent of photon-energy. While special relativity assumes that there is no fundamental length-scale associated with such invariance, there is a fundamental scale (the Planck scale, l(Planck) approximately 1.62 x 10(-33) cm or E(Planck) = M(Planck)c(2) approximately 1.22 x 10(19) GeV), at which quantum effects are expected to strongly affect the nature of space-time. There is great interest in the (not yet validated) idea that Lorentz invariance might break near the Planck scale. A key test of such violation of Lorentz invariance is a possible variation of photon speed with energy. Even a tiny variation in photon speed, when accumulated over cosmological light-travel times, may be revealed by observing sharp features in gamma-ray burst (GRB) light-curves. Here we report the detection of emission up to approximately 31 GeV from the distant and short GRB 090510. We find no evidence for the violation of Lorentz invariance, and place a lower limit of 1.2E(Planck) on the scale of a linear energy dependence (or an inverse wavelength dependence), subject to reasonable assumptions about the emission (equivalently we have an upper limit of l(Planck)/1.2 on the length scale of the effect). Our results disfavour quantum-gravity theories in which the quantum nature of space-time on a very small scale linearly alters the speed of light.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Abdo, A A -- Ackermann, M -- Ajello, M -- Asano, K -- Atwood, W B -- Axelsson, M -- Baldini, L -- Ballet, J -- Barbiellini, G -- Baring, M G -- Bastieri, D -- Bechtol, K -- Bellazzini, R -- Berenji, B -- Bhat, P N -- Bissaldi, E -- Bloom, E D -- Bonamente, E -- Bonnell, J -- Borgland, A W -- Bouvier, A -- Bregeon, J -- Brez, A -- Briggs, M S -- Brigida, M -- Bruel, P -- Burgess, J M -- Burnett, T H -- Caliandro, G A -- Cameron, R A -- Caraveo, P A -- Casandjian, J M -- Cecchi, C -- Celik, O -- Chaplin, V -- Charles, E -- Cheung, C C -- Chiang, J -- Ciprini, S -- Claus, R -- Cohen-Tanugi, J -- Cominsky, L R -- Connaughton, V -- Conrad, J -- Cutini, S -- Dermer, C D -- de Angelis, A -- de Palma, F -- Digel, S W -- Dingus, B L -- do Couto E Silva, E -- Drell, P S -- Dubois, R -- Dumora, D -- Farnier, C -- Favuzzi, C -- Fegan, S J -- Finke, J -- Fishman, G -- Focke, W B -- Foschini, L -- Fukazawa, Y -- Funk, S -- Fusco, P -- Gargano, F -- Gasparrini, D -- Gehrels, N -- Germani, S -- Gibby, L -- Giebels, B -- Giglietto, N -- Giordano, F -- Glanzman, T -- Godfrey, G -- Granot, J -- Greiner, J -- Grenier, I A -- Grondin, M-H -- Grove, J E -- Grupe, D -- Guillemot, L -- Guiriec, S -- Hanabata, Y -- Harding, A K -- Hayashida, M -- Hays, E -- Hoversten, E A -- Hughes, R E -- Johannesson, G -- Johnson, A S -- Johnson, R P -- Johnson, W N -- Kamae, T -- Katagiri, H -- Kataoka, J -- Kawai, N -- Kerr, M -- Kippen, R M -- Knodlseder, J -- Kocevski, D -- Kouveliotou, C -- Kuehn, F -- Kuss, M -- Lande, J -- Latronico, L -- Lemoine-Goumard, M -- Longo, F -- Loparco, F -- Lott, B -- Lovellette, M N -- Lubrano, P -- Madejski, G M -- Makeev, A -- Mazziotta, M N -- McBreen, S -- McEnery, J E -- McGlynn, S -- Meszaros, P -- Meurer, C -- Michelson, P F -- Mitthumsiri, W -- Mizuno, T -- Moiseev, A A -- Monte, C -- Monzani, M E -- Moretti, E -- Morselli, A -- Moskalenko, I V -- Murgia, S -- Nakamori, T -- Nolan, P L -- Norris, J P -- Nuss, E -- Ohno, M -- Ohsugi, T -- Omodei, N -- Orlando, E -- Ormes, J F -- Ozaki, M -- Paciesas, W S -- Paneque, D -- Panetta, J H -- Parent, D -- Pelassa, V -- Pepe, M -- Pesce-Rollins, M -- Petrosian, V -- Piron, F -- Porter, T A -- Preece, R -- Raino, S -- Ramirez-Ruiz, E -- Rando, R -- Razzano, M -- Razzaque, S -- Reimer, A -- Reimer, O -- Reposeur, T -- Ritz, S -- Rochester, L S -- Rodriguez, A Y -- Roth, M -- Ryde, F -- Sadrozinski, H F-W -- Sanchez, D -- Sander, A -- Saz Parkinson, P M -- Scargle, J D -- Schalk, T L -- Sgro, C -- Siskind, E J -- Smith, D A -- Smith, P D -- Spandre, G -- Spinelli, P -- Stamatikos, M -- Stecker, F W -- Strickman, M S -- Suson, D J -- Tajima, H -- Takahashi, H -- Takahashi, T -- Tanaka, T -- Thayer, J B -- Thayer, J G -- Thompson, D J -- Tibaldo, L -- Toma, K -- Torres, D F -- Tosti, G -- Troja, E -- Uchiyama, Y -- Uehara, T -- Usher, T L -- van der Horst, A J -- Vasileiou, V -- Vilchez, N -- Vitale, V -- von Kienlin, A -- Waite, A P -- Wang, P -- Wilson-Hodge, C -- Winer, B L -- Wood, K S -- Wu, X F -- Yamazaki, R -- Ylinen, T -- Ziegler, M -- England -- Nature. 2009 Nov 19;462(7271):331-4. doi: 10.1038/nature08574. Epub 2009 Oct 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Space Science Division, Naval Research Laboratory, Washington, District of Columbia 20375, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19865083" target="_blank"〉PubMed〈/a〉

Description: Long duration gamma-ray bursts (GRBs) mark the explosive death of some massive stars and are a rare sub-class of type Ibc supernovae. They are distinguished by the production of an energetic and collimated relativistic outflow powered by a central engine (an accreting black hole or neutron star). Observationally, this outflow is manifested in the pulse of gamma-rays and a long-lived radio afterglow. Until now, central-engine-driven supernovae have been discovered exclusively through their gamma-ray emission, yet it is expected that a larger population goes undetected because of limited satellite sensitivity or beaming of the collimated emission away from our line of sight. In this framework, the recovery of undetected GRBs may be possible through radio searches for type Ibc supernovae with relativistic outflows. Here we report the discovery of luminous radio emission from the seemingly ordinary type Ibc SN 2009bb, which requires a substantial relativistic outflow powered by a central engine. A comparison with our radio survey of type Ibc supernovae reveals that the fraction harbouring central engines is low, about one per cent, measured independently from, but consistent with, the inferred rate of nearby GRBs. Independently, a second mildly relativistic supernova has been reported.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Soderberg, A M -- Chakraborti, S -- Pignata, G -- Chevalier, R A -- Chandra, P -- Ray, A -- Wieringa, M H -- Copete, A -- Chaplin, V -- Connaughton, V -- Barthelmy, S D -- Bietenholz, M F -- Chugai, N -- Stritzinger, M D -- Hamuy, M -- Fransson, C -- Fox, O -- Levesque, E M -- Grindlay, J E -- Challis, P -- Foley, R J -- Kirshner, R P -- Milne, P A -- Torres, M A P -- England -- Nature. 2010 Jan 28;463(7280):513-5. doi: 10.1038/nature08714.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, Massachusetts 02138, USA. asoderberg@cfa.harvard.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20110995" target="_blank"〉PubMed〈/a〉

Description: Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gammaray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Fermi LAT and Fermi GBM Collaborations -- Abdo, A A -- Ackermann, M -- Arimoto, M -- Asano, K -- Atwood, W B -- Axelsson, M -- Baldini, L -- Ballet, J -- Band, D L -- Barbiellini, G -- Baring, M G -- Bastieri, D -- Battelino, M -- Baughman, B M -- Bechtol, K -- Bellardi, F -- Bellazzini, R -- Berenji, B -- Bhat, P N -- Bissaldi, E -- Blandford, R D -- Bloom, E D -- Bogaert, G -- Bogart, J R -- Bonamente, E -- Bonnell, J -- Borgland, A W -- Bouvier, A -- Bregeon, J -- Brez, A -- Briggs, M S -- Brigida, M -- Bruel, P -- Burnett, T H -- Burrows, D -- Busetto, G -- Caliandro, G A -- Cameron, R A -- Caraveo, P A -- Casandjian, J M -- Ceccanti, M -- Cecchi, C -- Celotti, A -- Charles, E -- Chekhtman, A -- Cheung, C C -- Chiang, J -- Ciprini, S -- Claus, R -- Cohen-Tanugi, J -- Cominsky, L R -- Connaughton, V -- Conrad, J -- Costamante, L -- Cutini, S -- Deklotz, M -- Dermer, C D -- de Angelis, A -- de Palma, F -- Digel, S W -- Dingus, B L -- do Couto E Silva, E -- Drell, P S -- Dubois, R -- Dumora, D -- Edmonds, Y -- Evans, P A -- Fabiani, D -- Farnier, C -- Favuzzi, C -- Finke, J -- Fishman, G -- Focke, W B -- Frailis, M -- Fukazawa, Y -- Funk, S -- Fusco, P -- Gargano, F -- Gasparrini, D -- Gehrels, N -- Germani, S -- Giebels, B -- Giglietto, N -- Giommi, P -- Giordano, F -- Glanzman, T -- Godfrey, G -- Goldstein, A -- Granot, J -- Greiner, J -- Grenier, I A -- Grondin, M-H -- Grove, J E -- Guillemot, L -- Guiriec, S -- Haller, G -- Hanabata, Y -- Harding, A K -- Hayashida, M -- Hays, E -- Hernando Morat, J A -- Hoover, A -- Hughes, R E -- Johannesson, G -- Johnson, A S -- Johnson, R P -- Johnson, T J -- Johnson, W N -- Kamae, T -- Katagiri, H -- Kataoka, J -- Kavelaars, A -- Kawai, N -- Kelly, H -- Kennea, J -- Kerr, M -- Kippen, R M -- Knodlseder, J -- Kocevski, D -- Kocian, M L -- Komin, N -- Kouveliotou, C -- Kuehn, F -- Kuss, M -- Lande, J -- Landriu, D -- Larsson, S -- Latronico, L -- Lavalley, C -- Lee, B -- Lee, S-H -- Lemoine-Goumard, M -- Lichti, G G -- Longo, F -- Loparco, F -- Lott, B -- Lovellette, M N -- Lubrano, P -- Madejski, G M -- Makeev, A -- Marangelli, B -- Mazziotta, M N -- McBreen, S -- McEnery, J E -- McGlynn, S -- Meegan, C -- Meszaros, P -- Meurer, C -- Michelson, P F -- Minuti, M -- Mirizzi, N -- Mitthumsiri, W -- Mizuno, T -- Moiseev, A A -- Monte, C -- Monzani, M E -- Moretti, E -- Morselli, A -- Moskalenko, I V -- Murgia, S -- Nakamori, T -- Nelson, D -- Nolan, P L -- Norris, J P -- Nuss, E -- Ohno, M -- Ohsugi, T -- Okumura, A -- Omodei, N -- Orlando, E -- Ormes, J F -- Ozaki, M -- Paciesas, W S -- Paneque, D -- Panetta, J H -- Parent, D -- Pelassa, V -- Pepe, M -- Perri, M -- Pesce-Rollins, M -- Petrosian, V -- Pinchera, M -- Piron, F -- Porter, T A -- Preece, R -- Raino, S -- Ramirez-Ruiz, E -- Rando, R -- Rapposelli, E -- Razzano, M -- Razzaque, S -- Rea, N -- Reimer, A -- Reimer, O -- Reposeur, T -- Reyes, L C -- Ritz, S -- Rochester, L S -- Rodriguez, A Y -- Roth, M -- Ryde, F -- Sadrozinski, H F-W -- Sanchez, D -- Sander, A -- Saz Parkinson, P M -- Scargle, J D -- Schalk, T L -- Segal, K N -- Sgro, C -- Shimokawabe, T -- Siskind, E J -- Smith, D A -- Smith, P D -- Spandre, G -- Spinelli, P -- Stamatikos, M -- Starck, J-L -- Stecker, F W -- Steinle, H -- Stephens, T E -- Strickman, M S -- Suson, D J -- Tagliaferri, G -- Tajima, H -- Takahashi, H -- Takahashi, T -- Tanaka, T -- Tenze, A -- Thayer, J B -- Thayer, J G -- Thompson, D J -- Tibaldo, L -- Torres, D F -- Tosti, G -- Tramacere, A -- Turri, M -- Tuvi, S -- Usher, T L -- van der Horst, A J -- Vigiani, L -- Vilchez, N -- Vitale, V -- von Kienlin, A -- Waite, A P -- Williams, D A -- Wilson-Hodge, C -- Winer, B L -- Wood, K S -- Wu, X F -- Yamazaki, R -- Ylinen, T -- Ziegler, M -- New York, N.Y. -- Science. 2009 Mar 27;323(5922):1688-93. doi: 10.1126/science.1169101. Epub 2009 Feb 19.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/19228997" target="_blank"〉PubMed〈/a〉

Description: Gamma-ray burst (GRB) 130427A is one of the most energetic GRBs ever observed. The initial pulse up to 2.5 seconds is possibly the brightest well-isolated pulse observed to date. A fine time resolution spectral analysis shows power-law decays of the peak energy from the onset of the pulse, consistent with models of internal synchrotron shock pulses. However, a strongly correlated power-law behavior is observed between the luminosity and the spectral peak energy that is inconsistent with curvature effects arising in the relativistic outflow. It is difficult for any of the existing models to account for all of the observed spectral and temporal behaviors simultaneously.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Preece, R -- Burgess, J Michael -- von Kienlin, A -- Bhat, P N -- Briggs, M S -- Byrne, D -- Chaplin, V -- Cleveland, W -- Collazzi, A C -- Connaughton, V -- Diekmann, A -- Fitzpatrick, G -- Foley, S -- Gibby, M -- Giles, M -- Goldstein, A -- Greiner, J -- Gruber, D -- Jenke, P -- Kippen, R M -- Kouveliotou, C -- McBreen, S -- Meegan, C -- Paciesas, W S -- Pelassa, V -- Tierney, D -- van der Horst, A J -- Wilson-Hodge, C -- Xiong, S -- Younes, G -- Yu, H-F -- Ackermann, M -- Ajello, M -- Axelsson, M -- Baldini, L -- Barbiellini, G -- Baring, M G -- Bastieri, D -- Bellazzini, R -- Bissaldi, E -- Bonamente, E -- Bregeon, J -- Brigida, M -- Bruel, P -- Buehler, R -- Buson, S -- Caliandro, G A -- Cameron, R A -- Caraveo, P A -- Cecchi, C -- Charles, E -- Chekhtman, A -- Chiang, J -- Chiaro, G -- Ciprini, S -- Claus, R -- Cohen-Tanugi, J -- Cominsky, L R -- Conrad, J -- D'Ammando, F -- de Angelis, A -- de Palma, F -- Dermer, C D -- Desiante, R -- Digel, S W -- Di Venere, L -- Drell, P S -- Drlica-Wagner, A -- Favuzzi, C -- Franckowiak, A -- Fukazawa, Y -- Fusco, P -- Gargano, F -- Gehrels, N -- Germani, S -- Giglietto, N -- Giordano, F -- Giroletti, M -- Godfrey, G -- Granot, J -- Grenier, I A -- Guiriec, S -- Hadasch, D -- Hanabata, Y -- Harding, A K -- Hayashida, M -- Iyyani, S -- Jogler, T -- Johannesson, G -- Kawano, T -- Knodlseder, J -- Kocevski, D -- Kuss, M -- Lande, J -- Larsson, J -- Larsson, S -- Latronico, L -- Longo, F -- Loparco, F -- Lovellette, M N -- Lubrano, P -- Mayer, M -- Mazziotta, M N -- Michelson, P F -- Mizuno, T -- Monzani, M E -- Moretti, E -- Morselli, A -- Murgia, S -- Nemmen, R -- Nuss, E -- Nymark, T -- Ohno, M -- Ohsugi, T -- Okumura, A -- Omodei, N -- Orienti, M -- Paneque, D -- Perkins, J S -- Pesce-Rollins, M -- Piron, F -- Pivato, G -- Porter, T A -- Racusin, J L -- Raino, S -- Rando, R -- Razzano, M -- Razzaque, S -- Reimer, A -- Reimer, O -- Ritz, S -- Roth, M -- Ryde, F -- Sartori, A -- Scargle, J D -- Schulz, A -- Sgro, C -- Siskind, E J -- Spandre, G -- Spinelli, P -- Suson, D J -- Tajima, H -- Takahashi, H -- Thayer, J G -- Thayer, J B -- Tibaldo, L -- Tinivella, M -- Torres, D F -- Tosti, G -- Troja, E -- Usher, T L -- Vandenbroucke, J -- Vasileiou, V -- Vianello, G -- Vitale, V -- Werner, M -- Winer, B L -- Wood, K S -- Zhu, S -- New York, N.Y. -- Science. 2014 Jan 3;343(6166):51-4. doi: 10.1126/science.1242302. Epub 2013 Nov 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24263132" target="_blank"〉PubMed〈/a〉

Description: The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of these unique astrophysical sources. GRB 130427A had the largest fluence, highest-energy photon (95 GeV), longest gamma-ray duration (20 hours), and one of the largest isotropic energy releases ever observed from a GRB. Temporal and spectral analyses of GRB 130427A challenge the widely accepted model that the nonthermal high-energy emission in the afterglow phase of GRBs is synchrotron emission radiated by electrons accelerated at an external shock.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ackermann, M -- Ajello, M -- Asano, K -- Atwood, W B -- Axelsson, M -- Baldini, L -- Ballet, J -- Barbiellini, G -- Baring, M G -- Bastieri, D -- Bechtol, K -- Bellazzini, R -- Bissaldi, E -- Bonamente, E -- Bregeon, J -- Brigida, M -- Bruel, P -- Buehler, R -- Burgess, J Michael -- Buson, S -- Caliandro, G A -- Cameron, R A -- Caraveo, P A -- Cecchi, C -- Chaplin, V -- Charles, E -- Chekhtman, A -- Cheung, C C -- Chiang, J -- Chiaro, G -- Ciprini, S -- Claus, R -- Cleveland, W -- Cohen-Tanugi, J -- Collazzi, A -- Cominsky, L R -- Connaughton, V -- Conrad, J -- Cutini, S -- D'Ammando, F -- de Angelis, A -- DeKlotz, M -- de Palma, F -- Dermer, C D -- Desiante, R -- Diekmann, A -- Di Venere, L -- Drell, P S -- Drlica-Wagner, A -- Favuzzi, C -- Fegan, S J -- Ferrara, E C -- Finke, J -- Fitzpatrick, G -- Focke, W B -- Franckowiak, A -- Fukazawa, Y -- Funk, S -- Fusco, P -- Gargano, F -- Gehrels, N -- Germani, S -- Gibby, M -- Giglietto, N -- Giles, M -- Giordano, F -- Giroletti, M -- Godfrey, G -- Granot, J -- Grenier, I A -- Grove, J E -- Gruber, D -- Guiriec, S -- Hadasch, D -- Hanabata, Y -- Harding, A K -- Hayashida, M -- Hays, E -- Horan, D -- Hughes, R E -- Inoue, Y -- Jogler, T -- Johannesson, G -- Johnson, W N -- Kawano, T -- Knodlseder, J -- Kocevski, D -- Kuss, M -- Lande, J -- Larsson, S -- Latronico, L -- Longo, F -- Loparco, F -- Lovellette, M N -- Lubrano, P -- Mayer, M -- Mazziotta, M N -- McEnery, J E -- Michelson, P F -- Mizuno, T -- Moiseev, A A -- Monzani, M E -- Moretti, E -- Morselli, A -- Moskalenko, I V -- Murgia, S -- Nemmen, R -- Nuss, E -- Ohno, M -- Ohsugi, T -- Okumura, A -- Omodei, N -- Orienti, M -- Paneque, D -- Pelassa, V -- Perkins, J S -- Pesce-Rollins, M -- Petrosian, V -- Piron, F -- Pivato, G -- Porter, T A -- Racusin, J L -- Raino, S -- Rando, R -- Razzano, M -- Razzaque, S -- Reimer, A -- Reimer, O -- Ritz, S -- Roth, M -- Ryde, F -- Sartori, A -- Parkinson, P M Saz -- Scargle, J D -- Schulz, A -- Sgro, C -- Siskind, E J -- Sonbas, E -- Spandre, G -- Spinelli, P -- Tajima, H -- Takahashi, H -- Thayer, J G -- Thayer, J B -- Thompson, D J -- Tibaldo, L -- Tinivella, M -- Torres, D F -- Tosti, G -- Troja, E -- Usher, T L -- Vandenbroucke, J -- Vasileiou, V -- Vianello, G -- Vitale, V -- Winer, B L -- Wood, K S -- Yamazaki, R -- Younes, G -- Yu, H-F -- Zhu, S J -- Bhat, P N -- Briggs, M S -- Byrne, D -- Foley, S -- Goldstein, A -- Jenke, P -- Kippen, R M -- Kouveliotou, C -- McBreen, S -- Meegan, C -- Paciesas, W S -- Preece, R -- Rau, A -- Tierney, D -- van der Horst, A J -- von Kienlin, A -- Wilson-Hodge, C -- Xiong, S -- Cusumano, G -- La Parola, V -- Cummings, J R -- New York, N.Y. -- Science. 2014 Jan 3;343(6166):42-7. doi: 10.1126/science.1242353. Epub 2013 Nov 21.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24263133" target="_blank"〉PubMed〈/a〉

Description: We report on the spectral analysis of individual Terrestrial Gamma-ray Flashes (TGFs) observed with the Fermi Gamma-ray Burst Monitor (GBM). The large GBM TGF sample provides 46 events suitable for individual spectral analysis: sufficiently bright, localized by ground-based radio, and with the gamma rays reaching a detector unobstructed. These TGFs exhibit diverse spectral characteristics that are hidden when using summed analysis methods. We account for the low counts in individual TGFs by using Poisson likelihood, and we also consider instrumental effects. The data are fit with models obtained from Monte Carlo simulations of the large scale Relativistic Runaway Electron Avalanche (RREA) model, including propagation through the atmosphere. Source altitudes ranging from 11.6 to 20.2 km are simulated. Two beaming geometries were considered: In one, the photons retain the intrinsic distribution from scattering (narrow), and in the other, the photons are smeared into a wider beam (wide). Several TGFs are well fit only by narrow models, while others favor wide models. Large-scale RREA models can accommodate both narrow and wide beams, with narrow beams suggest large-scale RREA in organized electric fields while wide beams may imply converging or diverging electric fields. Wide beams are also consistent with acceleration in the electric fields of lightning leaders, but the TGFs that favor narrow beam models appear inconsistent with some lightning leader models.