Browsing by Author "Caliandro, G.A."

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    The First Pulse of the Extremely Bright GRB 130427A: A Test Lab for Synchrotron Shocks
    (American Association for the Advancement of Science, 2014) 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.; Jóhannesson, G.; Kawano, T.; Knödlseder, 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.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Ritz, S.; Roth, M.; Ryde, F.; Sartori, A.; Scargle, J.D.; Schulz, A.; Sgrò, 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.
    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.
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    GRB110721A: An Extreme Peak Energy and Signatures of the Photosphere
    (The American Astronomical Society, 2012) Baring, M.G.; Axelsson, M.; Baldini, L.; Barbiellini, G.; Bellazzini, R.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Caliandro, G.A.; Cameron, R.A.; Caraveo, P.A.; Cecchi, C.; Chaves, R.C.G.; Chekhtman, A.; Chiang, J.; Claus, R.; Conrad, J.; Cutini, S.; D'Ammando, F.; de Palma, F.; Dermer, C.D.; do Couto e Silva, E.; Drell, P.S.; Favuzzi, C.; Fegan, S.J.; Ferrara, E.C.; Focke, W.B.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giroletti, M.; Godfrey, G.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Hayashida, M.; Hou, X.; Iyyani, S.; Jackson, M.S.; Kocevski, D.; Kuss, M.; Larsson, J.; Longo, F.; Loparco, F.; Lundman, C.; Mazziotta, M.N.; McEnery, J.E.; Mizuno, T.; Monzani, M.E.; Moretti, E.; Morselli, A.; Murgia, S.; Nuss, E.; Nymark, T.; Ohno, M.; Omodei, N.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Racusin, J.L.; Rainò, S.; Razzano, M.; Razzaque, S.; Reimer, A.; Roth, M.; Ryde, F.; Sanchez, D.A.; Sgrò, C.; Siskind, E.J.; Spandre, G.; Spinelli, P.; Stamatikos, M.; Tibaldo, L.; Tinivella, M.; Usher, T.L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A.P.; Winer, B.L.; Wood, K.S.; Burgess, J.M.; Bhat, P.N.; Bissaldi, E.; Briggs, M.S.; Connaughton, V.; Fishman, G.; Fitzpatrick, G.; Foley, S.; Gruber, D.; Kippen, R.M.; Kouveliotou, C.; Jenke, P.; McBreen, S.; McGlynn, S.; Meegan, C.; Paciesas, W.S.; Pelassa, V.; Preece, R.; Tierney, D.; von Kienlin, A.; Wilson-Hodge, C.; Xiong, S.; Pe'er, A.; Pe'er, A.
    GRB110721A was observed by the Fermi Gamma-ray Space Telescope using its two instruments, the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM). The burst consisted of one major emission episode which lasted for ~24.5 s (in the GBM) and had a peak flux of (5.7 ± 0.2) × 10–5 erg s–1 cm–2. The time-resolved emission spectrum is best modeled with a combination of a Band function and a blackbody spectrum. The peak energy of the Band component was initially 15 ± 2 MeV, which is the highest value ever detected in a GRB. This measurement was made possible by combining GBM/BGO data with LAT Low Energy events to achieve continuous 10-100 MeV coverage. The peak energy later decreased as a power law in time with an index of –1.89 ± 0.10. The temperature of the blackbody component also decreased, starting from ~80 keV, and the decay showed a significant break after ~2 s. The spectrum provides strong constraints on the standard synchrotron model, indicating that alternative mechanisms may give rise to the emission at these energies.
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    PSR J2021+4026 in the Gamma Cygni Region: The First Variable y-Ray Pulsar Seen by the Fermi Lat
    (The American Astronomical Society, 2013) Baring, M.G.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bonamente, E.; Bottacini, E.; Brandt, T.J.; Bregeon, J.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G.A.; Cameron, R.A.; Caraveo, P.A.; Cecchi, C.; Chaves, R.C.G.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Claus, R.; D'Ammando, F.; de Palma, F.; Digel, S.W.; Di Venere, L.; Drell, P.S.; Favuzzi, C.; Ferrara, E.C.; Franckowiak, A.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I.A.; Guiriec, S.; Hadasch, D.; Harding, A.K.; Hayashida, M.; Hayashi, K.; Hays, E.; Hewitt, J.; Hill, A.B.; Horan, D.; Hou, X.; Jogler, T.; Johnson, A.S.; Johnson, T.J.; Kerr, M.; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Latronico, L.; Lemoine-Goumard, M.; Lande, J.; Loparco, F.; Lubrano, P.; Malyshev, D.; Marelli, M.; Mayer, M.; Mazziotta, M.N.; Mehault, J.; Mizuno, T.; Monzani, M.E.; Morselli, A.; Murgia, S.; Nemmen, R.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Paneque, D.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Porter, T.A.; Rainò, S.; Rando, R.; Ray, P.S.; Razzano, M.; Reimer, O.; Reposeur, T.; Romani, R.W.; Sartori, A.; Saz Parkinson, P.M.; Sgrò, C.; Siskind, E.J.; Smith, D.A.; Spinelli, P.; Strong, A.W.; Takahashi, H.; Thayer, J.B.; Thompson, D.J.; Tibaldo, L.; Tinivella, M.; Torres, D.F.; Tosti, G.; Uchiyama, Y.; Usher, T.L.; Vandenbroucke, J.; Vasileiou, V.; Venter, C.; Vianello, G.; Vitale, V.; Winer, B.L.; Wood, K.S.
    Long-term monitoring of PSR J2021+4026 in the heart of the Cygnus region with the Fermi Large Area Telescope unveiled a sudden decrease in flux above 100 MeV over a timescale shorter than a week. The "jump" was near MJD 55850 (2011 October 16), with the flux decreasing from (8.33 ± 0.08) × 10–10 erg cm–2 s–1 to (6.86 ± 0.13) × 10–10 erg cm–2 s–1. Simultaneously, the frequency spindown rate increased from (7.8 ± 0.1) × 10–13 Hz s–1 to (8.1 ± 0.1) × 10–13 Hz s–1. Significant (>5σ) changes in the pulse profile and marginal (<3σ) changes in the emission spectrum occurred at the same time. There is also evidence for a small, steady flux increase over the 3 yr preceding MJD 55850. This is the first observation at γ-ray energies of mode changes and intermittent behavior, observed at radio wavelengths for other pulsars. We argue that the change in pulsed γ-ray emission is due to a change in emission beaming and we speculate that it is precipitated by a shift in the magnetic field structure, leading to a change of either effective magnetic inclination or effective current.
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    Searching the Gamma-Ray Sky for Counterparts to Gravitational Wave Sources: Fermi Gamma-Ray Burst Monitor and Large Area Telescope Observations of LVT151012 and GW151226
    (IOP, 2017) Racusin, J.L.; Burns, E.; Goldstein, A.; Connaughton, V.; Wilson-Hodge, C.A.; Jenke, P.; Blackburn, L.; Briggs, M.S.; Broida, J.; Camp, J.; Christensen, N.; Hui, C.M.; Littenberg, T.; Shawhan, P.; Singer, L.; Veitch, J.; Bhat, P.N.; Cleveland, W.; Fitzpatrick, G.; Gibby, M.H.; von Kienlin, A.; McBreen, S.; Mailyan, B.; Meegan, C.A.; Paciesas, W.S.; Preece, R.D.; Roberts, O.J.; Stanbro, M.; Veres, P.; Zhang, B.-B.; Fermi LAT Collaboration; Ackermann, M.; Albert, A.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Baring, M.G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R.D.; Bloom, E.D.; Bonino, R.; Bregeon, J.; Bruel, P.; Buson, S.; Caliandro, G.A.; Cameron, R.A.; Caputo, R.; Caragiulo, M.; Caraveo, P.A.; Cavazzuti, E.; Charles, E.; Chiang, J.; Ciprini, S.; Costanza, F.; Cuoco, A.; Cutini, S.; D'Ammando, F.; de Palma, F.; Desiante, R.; Digel, S.W.; Di Lalla, N.; Di Mauro, M.; Di Venere, L.; Drell, P.S.; Favuzzi, C.; Ferrara, E.C.; Focke, W.B.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Gill, R.; Giroletti, M.; Glanzman, T.; Granot, J.; Green, D.; Grove, J.E.; Guillemot, L.; Guiriec, S.; Harding, A.K.; Jogler, T.; Jóhannesson, G.; Kamae, T.; Kensei, S.; Kocevski, D.; Kuss, M.; Larsson, S.; Latronico, L.; Li, J.; Longo, F.; Loparco, F.; Lubrano, P.; Magill, J.D.; Maldera, S.; Malyshev, D.; Mazziotta, M.N.; McEnery, J.E.; Michelson, P.F.; Mizuno, T.; Monzani, M.E.; Morselli, A.; Moskalenko, I.V.; Negro, M.; Nuss, E.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J.F.; Paneque, D.; Perkins, J.S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T.A.; Principe, G.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Saz Parkinson, P.M.; Scargle, J.D.; Sgrò, C.; Simone, D.; Siskind, E.J.; Smith, D.A.; Spada, F.; Spinelli, P.; Suson, D.J.; Tajima, H.; Thayer, J.B.; Torres, D.F.; Troja, E.; Uchiyama, Y.; Vianello, G.; Wood, K.S.; Wood, M.
    We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candidate LVT151012. At the time of the LIGO triggers on LVT151012 and GW151226, GBM was observing 68% and 83% of the localization regions, and LAT was observing 47% and 32%, respectively. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for characterizing the flux upper bounds across large areas of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, differences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.