ALBERT

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 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: Asteroseismology, i.e. the study of the internal structures of stars via their global oscillations, is a valuable tool to obtain stellar parameters such as mass, radius, surface gravity and mean density. These parameters can be obtained using certain scaling relations which are based on an asymptotic approximation. Usually the observed oscillation parameters are assumed to follow these scaling relations. Recently, it has been questioned whether this is a valid approach, i.e. whether the order of the observed oscillation modes is high enough to be approximated with an asymptotic theory. In this work, we use stellar models to investigate whether the differences between observable oscillation parameters and their asymptotic estimates are indeed significant. We compute the asymptotic values directly from the stellar models and derive the observable values from adiabatic pulsation calculations of the same models. We find that the extent to which the atmosphere is included in the models is a key parameter. Considering a larger extension of the atmosphere beyond the photosphere reduces the difference between the asymptotic and observable values of the large frequency separation. Therefore, we conclude that the currently suggested discrepancies in the scaling relations might have been overestimated. Hence, based on the results presented here we believe that the suggestions of Mosser et al. should not be followed without careful consideration.

Description: The Hyades open cluster was targeted during Campaign 4 (C4) of the NASA K2 mission, and short-cadence data were collected on a number of cool main-sequence stars. Here, we report results on two F-type stars that show detectable oscillations of a quality that allows asteroseismic analyses to be performed. These are the first ever detections of solar-like oscillations in main-sequence stars in an open cluster.