Beitrag in einer Fachzeitschrift

Details zur Publikation

Autorinnen und Autoren: Ackermann M, Ajello M, Anderson B, Atwood WB, Axelsson M, Baldini L, Barbiellini G, Bastieri D, Bellazzini R, Bhat PN, Bissaldi E, Bonino R, Bottacini E, Brandt TJ, Bregeon J, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caragiulo M, Caraveo PA, Cecchi C, Charles E, Chekhtman A, Chiang J, Chiaro G, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Cutini S, D'Ammando F, De Angelis A, De Palma F, Desiante R, Di Venere L, Drell PS, Favuzzi C, Focke WB, Franckowiak A, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Giglietto N, Giordano F, Giroletti M, Godfrey G, Grenier IA, Grove JE, Guiriec S, Hewitt JW, Hill AB, Horan D, Johannesson G, Kocevski D, Kouveliotou C, Kuss M, Larsson S, Li J, Li L, Longo F, Loparco F, Lovellette MN, Lubrano P, Mayer M, Mazziotta MN, Mcenery JE, Michelson PF, Mizuno T, Monzani ME, Morselli A, Murgia S, Nemmen R, Nuss E, Ohno M, Ohsugi T, Omodei N, Orienti M, Orlando E, Paneque D, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Porter TA, Racusin JL, Raino S, Rando R, Razzano M, Reimer A, Reimer O, Schaal M, Schulz A, Sgro C, Siskind EJ, Spada F, Spandre G, Spinelli P, Takahashi H, Thayer JB, Tibaldo L, Tinivella M, Torres DF, Tosti G, Troja E, Vianello G, Von Kienlin A, Werner M, Wood KS
Zeitschrift: Astrophysical Journal
Verlag: American Astronomical Society
Jahr der Veröffentlichung: 2016
Band: 822
Heftnummer: 2
ISSN: 0004-637X
eISSN: 1538-4357


We perform a comprehensive stacking analysis of data collected by the Fermi. Large Area Telescope (LAT) of gamma-ray bursts (GRBs) localized by the Swift. spacecraft, which were not detected by the LAT but which fell within the instrument's field of view at the time of trigger. We examine a total of 79 GRBs by comparing the observed counts over a range of time intervals to that expected from designated background orbits, as well as by using a joint likelihood technique to model the expected distribution of stacked counts. We find strong evidence for subthreshold emission at MeV to GeV energies using both techniques. This observed excess is detected during intervals that include and exceed the durations typically characterizing the prompt emission observed at keV energies and lasts at least 2700 s after the co-aligned burst trigger. By utilizing a novel cumulative likelihood analysis, we find that although a burst's prompt gamma-ray and afterglow X-ray flux both correlate with the strength of the subthreshold emission, the X-ray afterglow flux measured by Swift's X-ray Telescope at 11 hr post trigger correlates far more significantly. Overall, the extended nature of the subthreshold emission and its connection to the burst's afterglow brightness lend. further support to the external forward shock origin of the late-time emission detected by the LAT. These results suggest that the extended high-energy emission observed by the LAT may be a relatively common feature but remains undetected in a majority of bursts owing. to instrumental threshold effects.

FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Funk, Stefan Prof. Dr.
Lehrstuhl für Physik

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Ackermann, M., Ajello, M., Anderson, B., Atwood, W.B., Axelsson, M., Baldini, L.,... Wood, K.S. (2016). FERMI LAT STACKING ANALYSIS OF SWIFT LOCALIZED GRBs. Astrophysical Journal, 822(2). https://dx.doi.org/10.3847/0004-637X/822/2/68

Ackermann, M., et al. "FERMI LAT STACKING ANALYSIS OF SWIFT LOCALIZED GRBs." Astrophysical Journal 822.2 (2016).


Zuletzt aktualisiert 2019-23-08 um 08:32