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17 results on '"Caliandro, G. A"'

1. Fermi-LAT observations of the gamma-ray burst GRB 130427A.

Author

Ackermann M, Ajello M, Asano K, Atwood WB, Axelsson M, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Bechtol K, Bellazzini R, Bissaldi E, Bonamente E, Bregeon J, Brigida M, Bruel P, Buehler R, Burgess JM, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cecchi C, Chaplin V, Charles E, Chekhtman A, Cheung CC, Chiang J, Chiaro G, Ciprini S, Claus R, Cleveland W, Cohen-Tanugi J, Collazzi A, Cominsky LR, Connaughton V, Conrad J, Cutini S, D'Ammando F, de Angelis A, DeKlotz M, de Palma F, Dermer CD, Desiante R, Diekmann A, Di Venere L, Drell PS, Drlica-Wagner A, Favuzzi C, Fegan SJ, Ferrara EC, Finke J, Fitzpatrick G, Focke WB, 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 IA, Grove JE, Gruber D, Guiriec S, Hadasch D, Hanabata Y, Harding AK, Hayashida M, Hays E, Horan D, Hughes RE, Inoue Y, Jogler T, Jóhannesson G, Johnson WN, Kawano T, Knödlseder J, Kocevski D, Kuss M, Lande J, Larsson S, Latronico L, Longo F, Loparco F, Lovellette MN, Lubrano P, Mayer M, Mazziotta MN, McEnery JE, Michelson PF, Mizuno T, Moiseev AA, Monzani ME, Moretti E, Morselli A, Moskalenko IV, Murgia S, Nemmen R, Nuss E, Ohno M, Ohsugi T, Okumura A, Omodei N, Orienti M, Paneque D, Pelassa V, Perkins JS, Pesce-Rollins M, Petrosian V, Piron F, Pivato G, Porter TA, Racusin JL, Rainò S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Ritz S, Roth M, Ryde F, Sartori A, Parkinson PM, Scargle JD, Schulz A, Sgrò C, Siskind EJ, Sonbas E, Spandre G, Spinelli P, Tajima H, Takahashi H, Thayer JG, Thayer JB, Thompson DJ, Tibaldo L, Tinivella M, Torres DF, Tosti G, Troja E, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Winer BL, Wood KS, Yamazaki R, Younes G, Yu HF, Zhu SJ, Bhat PN, Briggs MS, Byrne D, Foley S, Goldstein A, Jenke P, Kippen RM, Kouveliotou C, McBreen S, Meegan C, Paciesas WS, Preece R, Rau A, Tierney D, van der Horst AJ, von Kienlin A, Wilson-Hodge C, Xiong S, Cusumano G, La Parola V, and Cummings JR

Abstract

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 γ-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.

Published
2014
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2. The first pulse of the extremely bright GRB 130427A: a test lab for synchrotron shocks.

Author

Preece R, Burgess JM, von Kienlin A, Bhat PN, Briggs MS, Byrne D, Chaplin V, Cleveland W, Collazzi AC, Connaughton V, Diekmann A, Fitzpatrick G, Foley S, Gibby M, Giles M, Goldstein A, Greiner J, Gruber D, Jenke P, Kippen RM, Kouveliotou C, McBreen S, Meegan C, Paciesas WS, Pelassa V, Tierney D, van der Horst AJ, Wilson-Hodge C, Xiong S, Younes G, Yu HF, Ackermann M, Ajello M, Axelsson M, Baldini L, Barbiellini G, Baring MG, Bastieri D, Bellazzini R, Bissaldi E, Bonamente E, Bregeon J, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cecchi C, Charles E, Chekhtman A, Chiang J, Chiaro G, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Conrad J, D'Ammando F, de Angelis A, de Palma F, Dermer CD, Desiante R, Digel SW, Di Venere L, Drell PS, 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 IA, Guiriec S, Hadasch D, Hanabata Y, Harding AK, 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 MN, Lubrano P, Mayer M, Mazziotta MN, Michelson PF, Mizuno T, Monzani ME, 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 JS, Pesce-Rollins M, Piron F, Pivato G, Porter TA, Racusin JL, Rainò S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Ritz S, Roth M, Ryde F, Sartori A, Scargle JD, Schulz A, Sgrò C, Siskind EJ, Spandre G, Spinelli P, Suson DJ, Tajima H, Takahashi H, Thayer JG, Thayer JB, Tibaldo L, Tinivella M, Torres DF, Tosti G, Troja E, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Werner M, Winer BL, Wood KS, and Zhu S

Abstract

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.

Published
2014
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3. Detection of the characteristic pion-decay signature in supernova remnants.

Author

Ackermann M, Ajello M, Allafort A, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Bechtol K, Bellazzini R, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bottacini E, Brandt TJ, Bregeon J, Brigida M, Bruel P, Buehler R, Busetto G, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Celik O, Charles E, Chaty S, Chaves RC, Chekhtman A, Cheung CC, Chiang J, Chiaro G, Cillis AN, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Conrad J, Corbel S, Cutini S, D'Ammando F, de Angelis A, de Palma F, Dermer CD, do Couto e Silva E, Drell PS, Drlica-Wagner A, Falletti L, Favuzzi C, Ferrara EC, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Gargano F, Germani S, Giglietto N, Giommi P, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guiriec S, Hadasch D, Hanabata Y, Harding AK, Hayashida M, Hayashi K, Hays E, Hewitt JW, Hill AB, Hughes RE, Jackson MS, Jogler T, Jóhannesson G, Johnson AS, Kamae T, Kataoka J, Katsuta J, Knödlseder J, Kuss M, Lande J, Larsson S, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lovellette MN, Lubrano P, Madejski GM, Massaro F, Mayer M, Mazziotta MN, McEnery JE, Mehault J, Michelson PF, Mignani RP, Mitthumsiri W, Mizuno T, Moiseev AA, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Nemmen R, Nuss E, Ohno M, Ohsugi T, Omodei N, Orienti M, Orlando E, Ormes JF, Paneque D, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Rainò S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Ritz S, Romoli C, Sánchez-Conde M, Schulz A, Sgrò C, Simeon PE, Siskind EJ, Smith DA, Spandre G, Spinelli P, Stecker FW, Strong AW, Suson DJ, Tajima H, Takahashi H, Takahashi T, Tanaka T, Thayer JG, Thayer JB, Thompson DJ, Thorsett SE, Tibaldo L, Tibolla O, Tinivella M, Troja E, Uchiyama Y, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Waite AP, Werner M, Winer BL, Wood KS, Wood M, Yamazaki R, Yang Z, and Zimmer S

Abstract

Cosmic rays are particles (mostly protons) accelerated to relativistic speeds. Despite wide agreement that supernova remnants (SNRs) are the sources of galactic cosmic rays, unequivocal evidence for the acceleration of protons in these objects is still lacking. When accelerated protons encounter interstellar material, they produce neutral pions, which in turn decay into gamma rays. This offers a compelling way to detect the acceleration sites of protons. The identification of pion-decay gamma rays has been difficult because high-energy electrons also produce gamma rays via bremsstrahlung and inverse Compton scattering. We detected the characteristic pion-decay feature in the gamma-ray spectra of two SNRs, IC 443 and W44, with the Fermi Large Area Telescope. This detection provides direct evidence that cosmic-ray protons are accelerated in SNRs.

Published
2013
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4. Binary millisecond pulsar discovery via gamma-ray pulsations.

Author

Pletsch HJ, Guillemot L, Fehrmann H, Allen B, Kramer M, Aulbert C, Ackermann M, Ajello M, de Angelis A, Atwood WB, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Borgland AW, Bottacini E, Brandt TJ, Bregeon J, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Çelik Ö, Charles E, Chaves RC, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Cutini S, D'Ammando F, Dermer CD, Digel SW, Drell PS, Drlica-Wagner A, Dubois R, Dumora D, Favuzzi C, Ferrara EC, Franckowiak A, Fukazawa Y, Fusco P, Gargano F, Gehrels N, Germani S, Giglietto N, Giordano F, Giroletti M, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guiriec S, Hadasch D, Hanabata Y, Harding AK, den Hartog PR, Hayashida M, Hays E, Hill AB, Hou X, Hughes RE, Jóhannesson G, Jackson MS, Jogler T, Johnson AS, Johnson WN, Kataoka J, Kerr M, Knödlseder J, Kuss M, Lande J, Larsson S, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lovellette MN, Lubrano P, Massaro F, Mayer M, Mazziotta MN, McEnery JE, Mehault J, Michelson PF, Mitthumsiri W, Mizuno T, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Nemmen R, Nuss E, Ohno M, Ohsugi T, Omodei N, Orienti M, Orlando E, de Palma F, Paneque D, Perkins JS, Piron F, Pivato G, Porter TA, Rainò S, Rando R, Ray PS, Razzano M, Reimer A, Reimer O, Reposeur T, Ritz S, Romani RW, Romoli C, Sanchez DA, Saz Parkinson PM, Schulz A, Sgrò C, do Couto e Silva E, Siskind EJ, Smith DA, Spandre G, Spinelli P, Suson DJ, Takahashi H, Tanaka T, Thayer JB, Thayer JG, Thompson DJ, Tibaldo L, Tinivella M, Troja E, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Waite AP, Winer BL, Wood KS, Wood M, Yang Z, and Zimmer S

Abstract

Millisecond pulsars, old neutron stars spun up by accreting matter from a companion star, can reach high rotation rates of hundreds of revolutions per second. Until now, all such "recycled" rotation-powered pulsars have been detected by their spin-modulated radio emission. In a computing-intensive blind search of gamma-ray data from the Fermi Large Area Telescope (with partial constraints from optical data), we detected a 2.5-millisecond pulsar, PSR J1311-3430. This unambiguously explains a formerly unidentified gamma-ray source that had been a decade-long enigma, confirming previous conjectures. The pulsar is in a circular orbit with an orbital period of only 93 minutes, the shortest of any spin-powered pulsar binary ever found.

Published
2012
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5. The imprint of the extragalactic background light in the gamma-ray spectra of blazars.

Author

Ackermann M, Ajello M, Allafort A, Schady P, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bellazzini R, Blandford RD, Bloom ED, Borgland AW, Bottacini E, Bouvier A, Bregeon J, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cavazzuti E, Cecchi C, Charles E, Chaves RC, Chekhtman A, Cheung CC, Chiang J, Chiaro G, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Cutini S, D'Ammando F, de Palma F, Dermer CD, Digel SW, do Couto e Silva E, Domínguez A, Drell PS, Drlica-Wagner A, Favuzzi C, Fegan SJ, Focke WB, Franckowiak A, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grove JE, Guiriec S, Gustafsson M, Hadasch D, Hayashida M, Hays E, Jackson MS, Jogler T, Kataoka J, Knödlseder J, Kuss M, Lande J, Larsson S, Latronico L, Longo F, Loparco F, Lovellette MN, Lubrano P, Mazziotta MN, McEnery JE, Mehault J, Michelson PF, Mizuno T, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Tramacere A, Nuss E, Greiner J, Ohno M, Ohsugi T, Omodei N, Orienti M, Orlando E, Ormes JF, Paneque D, Perkins JS, Pesce-Rollins M, Piron F, Pivato G, Porter TA, Rainò S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Reyes LC, Ritz S, Rau A, Romoli C, Roth M, Sánchez-Conde M, Sanchez DA, Scargle JD, Sgrò C, Siskind EJ, Spandre G, Spinelli P, Stawarz Ł, Suson DJ, Takahashi H, Tanaka T, Thayer JG, Thompson DJ, Tibaldo L, Tinivella M, Torres DF, Tosti G, Troja E, Usher TL, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Waite AP, Winer BL, Wood KS, and Wood M

Abstract

The light emitted by stars and accreting compact objects through the history of the universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of star formation and galaxy evolution, but direct measurements of the EBL are limited by galactic and other foreground emissions. Here, we report an absorption feature seen in the combined spectra of a sample of gamma-ray blazars out to a redshift of z ∼ 1.6. This feature is caused by attenuation of gamma rays by the EBL at optical to ultraviolet frequencies and allowed us to measure the EBL flux density in this frequency band.

Published
2012
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6. Periodic emission from the gamma-ray binary 1FGL J1018.6-5856.

Author

Fermi LAT Collaboration, Ackermann M, Ajello M, Ballet J, Barbiellini G, Bastieri D, Belfiore A, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bregeon J, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Cavazzuti E, Cecchi C, Çelik Ö, Charles E, Chaty S, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Corbel S, Corbet RH, Cutini S, de Luca A, den Hartog PR, de Palma F, Dermer CD, Digel SW, do Couto e Silva E, Donato D, Drell PS, Drlica-Wagner A, Dubois R, Dubus G, Favuzzi C, Fegan SJ, Ferrara EC, Focke WB, Fortin P, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grove JE, Guiriec S, Hadasch D, Hanabata Y, Harding AK, Hayashida M, Hays E, Hill AB, Hughes RE, Jóhannesson G, Johnson AS, Johnson TJ, Kamae T, Katagiri H, Kataoka J, Kerr M, Knödlseder J, Kuss M, Lande J, Longo F, Loparco F, Lovellette MN, Lubrano P, Mazziotta MN, McEnery JE, Michelson PF, Mitthumsiri W, Mizuno T, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Naumann-Godo M, Norris JP, Nuss E, Ohno M, Ohsugi T, Okumura A, Omodei N, Orlando E, Ozaki M, Paneque D, Parent D, Pesce-Rollins M, Pierbattista M, Piron F, Pivato G, Porter TA, Rainò S, Rando R, Razzano M, Reimer A, Reimer O, Ritz S, Romani RW, Roth M, Saz Parkinson PM, Sgrò C, Siskind EJ, Spandre G, Spinelli P, Suson DJ, Takahashi H, Tanaka T, Thayer JG, Thayer JB, Thompson DJ, Tibaldo L, Tinivella M, Torres DF, Tosti G, Troja E, Uchiyama Y, Usher TL, Vandenbroucke J, Vianello G, Vitale V, Waite AP, Winer BL, Wood KS, Wood M, Yang Z, Zimmer S, Coe MJ, Di Mille F, Edwards PG, Filipović MD, Payne JL, Stevens J, and Torres MA

Abstract

Gamma-ray binaries are stellar systems containing a neutron star or black hole, with gamma-ray emission produced by an interaction between the components. These systems are rare, even though binary evolution models predict dozens in our Galaxy. A search for gamma-ray binaries with the Fermi Large Area Telescope (LAT) shows that 1FGL J1018.6-5856 exhibits intensity and spectral modulation with a 16.6-day period. We identified a variable x-ray counterpart, which shows a sharp maximum coinciding with maximum gamma-ray emission, as well as an O6V((f)) star optical counterpart and a radio counterpart that is also apparently modulated on the orbital period. 1FGL J1018.6-5856 is thus a gamma-ray binary, and its detection suggests the presence of other fainter binaries in the Galaxy.

Published
2012
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7. A cocoon of freshly accelerated cosmic rays detected by Fermi in the Cygnus superbubble.

Author

Ackermann M, Ajello M, Allafort A, Baldini L, Ballet J, Barbiellini G, Bastieri D, Belfiore A, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bottacini E, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, de Angelis A, de Palma F, Dermer CD, do Couto E Silva E, Drell PS, Dumora D, Favuzzi C, Fegan SJ, Focke WB, Fortin P, Fukazawa Y, Fusco P, Gargano F, Germani S, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Guillemot L, Guiriec S, Hadasch D, Hanabata Y, Harding AK, Hayashida M, Hayashi K, Hays E, Jóhannesson G, Johnson AS, Kamae T, Katagiri H, Kataoka J, Kerr M, Knödlseder J, Kuss M, Lande J, Latronico L, Lee SH, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Martin P, Mazziotta MN, McEnery JE, Mehault J, Michelson PF, Mitthumsiri W, Mizuno T, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Naumann-Godo M, Nolan PL, Norris JP, Nuss E, Ohsugi T, Okumura A, Orlando E, Ormes JF, Ozaki M, Paneque D, Parent D, Pesce-Rollins M, Pierbattista M, Piron F, Pohl M, Prokhorov D, Rainò S, Rando R, Razzano M, Reposeur T, Ritz S, Parkinson PM, Sgrò C, Siskind EJ, Smith PD, Spinelli P, Strong AW, Takahashi H, Tanaka T, Thayer JG, Thayer JB, Thompson DJ, Tibaldo L, Torres DF, Tosti G, Tramacere A, Troja E, Uchiyama Y, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Waite AP, Wang P, Winer BL, Wood KS, Yang Z, Zimmer S, and Bontemps S

Abstract

The origin of Galactic cosmic rays is a century-long puzzle. Indirect evidence points to their acceleration by supernova shockwaves, but we know little of their escape from the shock and their evolution through the turbulent medium surrounding massive stars. Gamma rays can probe their spreading through the ambient gas and radiation fields. The Fermi Large Area Telescope (LAT) has observed the star-forming region of Cygnus X. The 1- to 100-gigaelectronvolt images reveal a 50-parsec-wide cocoon of freshly accelerated cosmic rays that flood the cavities carved by the stellar winds and ionization fronts from young stellar clusters. It provides an example to study the youth of cosmic rays in a superbubble environment before they merge into the older Galactic population.

Published
2011
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8. Gamma-ray flares from the Crab Nebula.

Author

Abdo AA, Ackermann M, Ajello M, Allafort A, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bouvier A, Brandt TJ, Bregeon J, Brez A, Brigida M, Bruel P, Buehler R, Buson S, Caliandro GA, Cameron RA, Cannon A, Caraveo PA, Casandjian JM, Çelik Ö, Charles E, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Costamante L, Cutini S, D'Ammando F, Dermer CD, de Angelis A, de Luca A, de Palma F, Digel SW, do Couto e Silva E, Drell PS, Drlica-Wagner A, Dubois R, Dumora D, Favuzzi C, Fegan SJ, Ferrara EC, Focke WB, Fortin P, Frailis M, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guiriec S, Hadasch D, Hanabata Y, Harding AK, Hayashi K, Hayashida M, Hays E, Horan D, Itoh R, Jóhannesson G, Johnson AS, Johnson TJ, Khangulyan D, Kamae T, Katagiri H, Kataoka J, Kerr M, Knödlseder J, Kuss M, Lande J, Latronico L, Lee SH, Lemoine-Goumard M, Longo F, Loparco F, Lubrano P, Madejski GM, Makeev A, Marelli M, Mazziotta MN, McEnery JE, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Naumann-Godo M, Nolan PL, Norris JP, Nuss E, Ohsugi T, Okumura A, Omodei N, Ormes JF, Ozaki M, Paneque D, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Pierbattista M, Piron F, Porter TA, Rainò S, Rando R, Ray PS, Razzano M, Reimer A, Reimer O, Reposeur T, Ritz S, Romani RW, Sadrozinski HF, Sanchez D, Saz Parkinson PM, Scargle JD, Schalk TL, Sgrò C, Siskind EJ, Smith PD, Spandre G, Spinelli P, Strickman MS, Suson DJ, Takahashi H, Takahashi T, Tanaka T, Thayer JB, Thompson DJ, Tibaldo L, Torres DF, Tosti G, Tramacere A, Troja E, Uchiyama Y, Vandenbroucke J, Vasileiou V, Vianello G, Vitale V, Wang P, Wood KS, Yang Z, and Ziegler M

Abstract

A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 and lasted approximately 16 days. The second flare was detected in September 2010 and lasted approximately 4 days. During these outbursts, the gamma-ray flux from the nebula increased by factors of four and six, respectively. The brevity of the flares implies that the gamma rays were emitted via synchrotron radiation from peta-electron-volt (10(15) electron volts) electrons in a region smaller than 1.4 × 10(-2) parsecs. These are the highest-energy particles that can be associated with a discrete astronomical source, and they pose challenges to particle acceleration theory.

Published
2011
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9. Gamma-ray emission concurrent with the nova in the symbiotic binary V407 Cygni.

Author

Abdo AA, Ackermann M, Ajello M, Atwood WB, Baldini L, Ballet J, Barbiellini G, Bastieri D, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bouvier A, Brandt TJ, Bregeon J, Brez A, Brigida M, Bruel P, Buehler R, Burnett TH, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Carrigan S, Casandjian JM, Cecchi C, Celik O, Charles E, Chaty S, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Corbel S, Corbet R, DeCesar ME, den Hartog PR, Dermer CD, de Palma F, Digel SW, Donato D, do Couto e Silva E, Drell PS, Dubois R, Dubus G, Dumora D, Favuzzi C, Fegan SJ, Ferrara EC, Fortin P, Frailis M, Fuhrmann L, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guiriec S, Hadasch D, Harding AK, Hayashida M, Hays E, Healey SE, Hill AB, Horan D, Hughes RE, Itoh R, Jean P, Jóhannesson G, Johnson AS, Johnson RP, Johnson TJ, Johnson WN, Kamae T, Katagiri H, Kataoka J, Kerr M, Knödlseder J, Koerding E, Kuss M, Lande J, Latronico L, Lee SH, Lemoine-Goumard M, Garde ML, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Makeev A, Mazziotta MN, McConville W, McEnery JE, Mehault J, Michelson PF, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Naumann-Godo M, Nestoras I, Nolan PL, Norris JP, Nuss E, Ohno M, Ohsugi T, Okumura A, Omodei N, Orlando E, Ormes JF, Ozaki M, Paneque D, Panetta JH, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Piron F, Porter TA, Rainò S, Rando R, Ray PS, Razzano M, Razzaque S, Rea N, Reimer A, Reimer O, Reposeur T, Ripken J, Ritz S, Romani RW, Roth M, Sadrozinski HF, Sander A, Parkinson PM, Scargle JD, Schinzel FK, Sgrò C, Shaw MS, Siskind EJ, Smith DA, Smith PD, Sokolovsky KV, Spandre G, Spinelli P, Stawarz Ł, Strickman MS, Suson DJ, Takahashi H, Takahashi T, Tanaka T, Tanaka Y, Thayer JB, Thayer JG, Thompson DJ, Tibaldo L, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Usher TL, Vandenbroucke J, Vasileiou V, Vilchez N, Vitale V, Waite AP, Wallace E, Wang P, Winer BL, Wolff MT, Wood KS, Yang Z, Ylinen T, Ziegler M, Maehara H, Nishiyama K, Kabashima F, Bach U, Bower GC, Falcone A, Forster JR, Henden A, Kawabata KS, Koubsky P, Mukai K, Nelson T, Oates SR, Sakimoto K, Sasada M, Shenavrin VI, Shore SN, Skinner GK, Sokoloski J, Stroh M, Tatarnikov AM, Uemura M, Wahlgren GM, and Yamanaka M

Abstract

Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable gamma-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce pi(0) decay gamma-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.

Published
2010
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10. Fermi gamma-ray imaging of a radio galaxy.

Author

Abdo AA, Ackermann M, Ajello M, Atwood WB, Baldini L, Ballet J, Barbiellini G, Bastieri D, Baughman BM, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bregeon J, Brez A, Brigida M, Bruel P, Burnett TH, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cavazzuti E, Cecchi C, Celik O, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Colafrancesco S, Cominsky LR, Conrad J, Costamante L, Cutini S, Davis DS, Dermer CD, de Angelis A, de Palma F, Digel SW, do Couto e Silva E, Drell PS, Dubois R, Dumora D, Farnier C, Favuzzi C, Fegan SJ, Finke J, Focke WB, Fortin P, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Georganopoulos M, Germani S, Giebels B, Giglietto N, Giordano F, Giroletti M, Glanzman T, Godfrey G, Grenier IA, Grove JE, Guillemot L, Guiriec S, Hanabata Y, Harding AK, Hayashida M, Hays E, Hughes RE, Jackson MS, Jóhannesson G, Johnson AS, Johnson TJ, Johnson WN, Kamae T, Katagiri H, Kataoka J, Kawai N, Kerr M, Knödlseder J, Kocian ML, Kuss M, Lande J, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Madejski GM, Makeev A, Mazziotta MN, McConville W, McEnery JE, Meurer C, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nolan PL, Norris JP, Nuss E, Ohsugi T, Omodei N, Orlando E, Ormes JF, Paneque D, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Piron F, Porter TA, Rainò S, Rando R, Razzano M, Razzaque S, Reimer A, Reimer O, Reposeur T, Ritz S, Rochester LS, Rodriguez AY, Romani RW, Roth M, Ryde F, Sadrozinski HF, Sambruna R, Sanchez D, Sander A, Saz Parkinson PM, Scargle JD, Sgrò C, Siskind EJ, Smith DA, Smith PD, Spandre G, Spinelli P, Starck JL, Stawarz Ł, Strickman MS, Suson DJ, Tajima H, Takahashi H, Takahashi T, Tanaka T, Thayer JB, Thayer JG, Thompson DJ, Tibaldo L, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Usher TL, Vasileiou V, Vilchez N, Vitale V, Waite AP, Wallace E, Wang P, Winer BL, Wood KS, Ylinen T, Ziegler M, Hardcastle MJ, and Kazanas D

Abstract

The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating from the giant radio lobes of the radio galaxy Centaurus A. The resolved gamma-ray image shows the lobes clearly separated from the central active source. In contrast to all other active galaxies detected so far in high-energy gamma-rays, the lobe flux constitutes a considerable portion (greater than one-half) of the total source emission. The gamma-ray emission from the lobes is interpreted as inverse Compton-scattered relic radiation from the cosmic microwave background, with additional contribution at higher energies from the infrared-to-optical extragalactic background light. These measurements provide gamma-ray constraints on the magnetic field and particle energy content in radio galaxy lobes, as well as a promising method to probe the cosmic relic photon fields.

Published
2010
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11. Gamma-ray emission from the shell of supernova remnant W44 revealed by the Fermi LAT.

Author

Abdo AA, Ackermann M, Ajello M, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Baughman BM, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bregeon J, Brez A, Brigida M, Bruel P, Burnett TH, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Celik O, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cognard I, Cohen-Tanugi J, Cominsky LR, Conrad J, Cutini S, Dermer CD, de Angelis A, de Palma F, Digel SW, do Couto e Silva E, Drell PS, Dubois R, Dumora D, Espinoza C, Farnier C, Favuzzi C, Fegan SJ, Focke WB, Fortin P, Frailis M, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giavitto G, Giebels B, Giglietto N, Giordano F, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guillemot L, Guiriec S, Hanabata Y, Harding AK, Hayashida M, Hays E, Hughes RE, Jackson MS, Jóhannesson G, Johnson AS, Johnson TJ, Johnson WN, Kamae T, Katagiri H, Kataoka J, Katsuta J, Kawai N, Kerr M, Knödlseder J, Kocian ML, Kramer M, Kuss M, Lande J, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Lyne AG, Madejski GM, Makeev A, Mazziotta MN, McEnery JE, Meurer C, Michelson PF, Mitthumsiri W, Mizuno T, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Nolan PL, Norris JP, Noutsos A, Nuss E, Ohsugi T, Omodei N, Orlando E, Ormes JF, Paneque D, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Piron F, Porter TA, Rainò S, Rando R, Razzano M, Reimer A, Reimer O, Reposeur T, Rochester LS, Rodriguez AY, Romani RW, Roth M, Ryde F, Sadrozinski HF, Sanchez D, Sander A, Saz Parkinson PM, Scargle JD, Sgrò C, Siskind EJ, Smith DA, Smith PD, Spandre G, Spinelli P, Stappers BW, Stecker FW, Strickman MS, Suson DJ, Tajima H, Takahashi H, Takahashi T, Tanaka T, Thayer JB, Thayer JG, Theureau G, Thompson DJ, Tibaldo L, Tibolla O, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Usher TL, Vasileiou V, Venter C, Vilchez N, Vitale V, Waite AP, Wang P, Winer BL, Wood KS, Yamazaki R, Ylinen T, and Ziegler M

Abstract

Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to ~10(15) electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 x 10(8) electron volts and 3 x10(11) electron volts. The detection of a source with a morphology corresponding to the SNR shell implies that the emission is produced by particles accelerated there. The gamma-ray spectrum is well modeled with emission from protons and nuclei. Its steepening above approximately 10(9) electron volts provides a probe with which to study how particle acceleration responds to environmental effects such as shock propagation in dense clouds and how accelerated particles are released into interstellar space.

Published
2010
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12. Modulated high-energy gamma-ray emission from the microquasar Cygnus X-3.

Author

Abdo AA, Ackermann M, Ajello M, Axelsson M, Baldini L, Ballet J, Barbiellini G, Bastieri D, Baughman BM, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Brez A, Brigida M, Bruel P, Burnett TH, Buson S, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Celik O, Chaty S, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Conrad J, Corbel S, Corbet R, Dermer CD, de Palma F, Digel SW, do Couto e Silva E, Drell PS, Dubois R, Dubus G, Dumora D, Farnier C, Favuzzi C, Fegan SJ, Focke WB, Fortin P, Frailis M, Fusco P, Gargano F, Gehrels N, Germani S, Giavitto G, Giebels B, Giglietto N, Giordano F, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guillemot L, Guiriec S, Hanabata Y, Harding AK, Hayashida M, Hays E, Hill AB, Hjalmarsdotter L, Horan D, Hughes RE, Jackson MS, Jóhannesson G, Johnson AS, Johnson TJ, Johnson WN, Kamae T, Katagiri H, Kawai N, Kerr M, Knödlseder J, Kocian ML, Koerding E, Kuss M, Lande J, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Madejski GM, Makeev A, Marchand L, Marelli M, Max-Moerbeck W, Mazziotta MN, McColl N, McEnery JE, Meurer C, Michelson PF, Migliari S, Mitthumsiri W, Mizuno T, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nolan PL, Norris JP, Nuss E, Ohsugi T, Omodei N, Ong RA, Ormes JF, Paneque D, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Piron F, Pooley G, Porter TA, Pottschmidt K, Rainò S, Rando R, Ray PS, Razzano M, Rea N, Readhead A, Reimer A, Reimer O, Richards JL, Rochester LS, Rodriguez J, Rodriguez AY, Romani RW, Ryde F, Sadrozinski HF, Sander A, Saz Parkinson PM, Sgrò C, Siskind EJ, Smith DA, Smith PD, Spinelli P, Starck JL, Stevenson M, Strickman MS, Suson DJ, Takahashi H, Tanaka T, Thayer JB, Thompson DJ, Tibaldo L, Tomsick JA, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Usher TL, Vasileiou V, Vilchez N, Vitale V, Waite AP, Wang P, Wilms J, Winer BL, Wood KS, Ylinen T, and Ziegler M

Abstract

Microquasars are accreting black holes or neutron stars in binary systems with associated relativistic jets. Despite their frequent outburst activity, they have never been unambiguously detected emitting high-energy gamma rays. The Fermi Large Area Telescope (LAT) has detected a variable high-energy source coinciding with the position of the x-ray binary and microquasar Cygnus X-3. Its identification with Cygnus X-3 is secured by the detection of its orbital period in gamma rays, as well as the correlation of the LAT flux with radio emission from the relativistic jets of Cygnus X-3. The gamma-ray emission probably originates from within the binary system, opening new areas in which to study the formation of relativistic jets.

Published
2009
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13. Detection of 16 gamma-ray pulsars through blind frequency searches using the Fermi LAT.

Author

Abdo AA, Ackermann M, Ajello M, Anderson B, Atwood WB, Axelsson M, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Baughman BM, Bechtol K, Bellazzini R, Berenji B, Bignami GF, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bregeon J, Brez A, Brigida M, Bruel P, Burnett TH, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Celik O, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Cutini S, Dermer CD, de Angelis A, de Luca A, de Palma F, Digel SW, Dormody M, do Couto e Silva E, Drell PS, Dubois R, Dumora D, Farnier C, Favuzzi C, Fegan SJ, 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, Grenier IA, Grondin MH, Grove JE, Guillemot L, Guiriec S, Gwon C, Hanabata Y, Harding AK, Hayashida M, Hays E, Hughes RE, Jóhannesson G, Johnson RP, Johnson TJ, Johnson WN, Kamae T, Katagiri H, Kataoka J, Kawai N, Kerr M, Knödlseder J, Kocian ML, Kuss M, Lande J, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Madejski GM, Makeev A, Marelli M, Mazziotta MN, McConville W, McEnery JE, Meurer C, Michelson PF, Mitthumsiri W, Mizuno T, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nolan PL, Norris JP, Nuss E, Ohsugi T, Omodei N, Orlando E, Ormes JF, Paneque D, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Pierbattista M, Piron F, Porter TA, Primack JR, Rainò S, Rando R, Ray PS, Razzano M, Rea N, Reimer A, Reimer O, Reposeur T, Ritz S, Rochester LS, Rodriguez AY, Romani RW, Ryde F, Sadrozinski HF, Sanchez D, Sander A, Saz Parkinson PM, Scargle JD, Sgrò C, Siskind EJ, Smith DA, Smith PD, Spandre G, Spinelli P, Starck JL, Strickman MS, Suson DJ, Tajima H, Takahashi H, Takahashi T, Tanaka T, Thayer JG, Thompson DJ, Tibaldo L, Tibolla O, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Usher TL, Van Etten A, Vasileiou V, Vilchez N, Vitale V, Waite AP, Wang P, Watters K, Winer BL, Wolff MT, Wood KS, Ylinen T, and Ziegler M

Abstract

Pulsars are rapidly rotating, highly magnetized neutron stars emitting radiation across the electromagnetic spectrum. Although there are more than 1800 known radio pulsars, until recently only seven were observed to pulse in gamma rays, and these were all discovered at other wavelengths. The Fermi Large Area Telescope (LAT) makes it possible to pinpoint neutron stars through their gamma-ray pulsations. We report the detection of 16 gamma-ray pulsars in blind frequency searches using the LAT. Most of these pulsars are coincident with previously unidentified gamma-ray sources, and many are associated with supernova remnants. Direct detection of gamma-ray pulsars enables studies of emission mechanisms, population statistics, and the energetics of pulsar wind nebulae and supernova remnants.

Published
2009
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14. Detection of high-energy gamma-ray emission from the globular cluster 47 Tucanae with Fermi.

Author

Abdo AA, Ackermann M, Ajello M, Atwood WB, Axelsson M, Baldini L, Ballet J, Barbiellini G, Bastieri D, Baughman BM, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bregeon J, Brez A, Brigida M, Bruel P, Burnett TH, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Cecchi C, Celik O, Charles E, Chaty S, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Conrad J, Cutini S, Dermer CD, de Palma F, Digel SW, Dormody M, do Couto e Silva E, Drell PS, Dubois R, Dumora D, Farnier C, Favuzzi C, Fegan SJ, Focke WB, Frailis M, Fukazawa Y, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giebels B, Giglietto N, Giordano F, Glanzman T, Godfrey G, Grenier IA, Grove JE, Guillemot L, Guiriec S, Hanabata Y, Harding AK, Hayashida M, Hays E, Horan D, Hughes RE, Jóhannesson G, Johnson AS, Johnson RP, Johnson TJ, Johnson WN, Kamae T, Katagiri H, Kawai N, Kerr M, Knödlseder J, Kuehn F, Kuss M, Lande J, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Makeev A, Mazziotta MN, McConville W, McEnery JE, Meurer C, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nolan PL, Norris JP, Nuss E, Ohsugi T, Omodei N, Orlando E, Ormes JF, Paneque D, Panetta JH, Parent D, Pelassa V, Pepe M, Pierbattista M, Piron F, Porter TA, Rainò S, Rando R, Razzano M, Rea N, Reimer A, Reimer O, Reposeur T, Ritz S, Rochester LS, Rodriguez AY, Romani RW, Roth M, Ryde F, Sadrozinski HF, Sanchez D, Sander A, Saz Parkinson PM, Sgrò C, Smith DA, Smith PD, Spandre G, Spinelli P, Starck JL, Strickman MS, Suson DJ, Tajima H, Takahashi H, Tanaka T, Thayer JB, Thayer JG, Thompson DJ, Tibaldo L, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Usher TL, Vasileiou V, Vilchez N, Vitale V, Wang P, Webb N, Winer BL, Wood KS, Ylinen T, and Ziegler M

Abstract

We report the detection of gamma-ray emissions above 200 megaelectron volts at a significance level of 17sigma from the globular cluster 47 Tucanae, using data obtained with the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Globular clusters are expected to emit gamma rays because of the large populations of millisecond pulsars that they contain. The spectral shape of 47 Tucanae is consistent with gamma-ray emission from a population of millisecond pulsars. The observed gamma-ray luminosity implies an upper limit of 60 millisecond pulsars present in 47 Tucanae.

Published
2009
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15. A population of gamma-ray millisecond pulsars seen with the Fermi Large Area Telescope.

Author

Abdo AA, Ackermann M, Ajello M, Atwood WB, Axelsson M, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Baughman BM, Bechtol K, Bellazzini R, Berenji B, Bignami GF, Blandford RD, Bloom ED, Bonamente E, Borgland AW, Bregeon J, Brez A, Brigida M, Bruel P, Burnett TH, Caliandro GA, Cameron RA, Camilo F, Caraveo PA, Carlson P, Casandjian J, Cecchi C, Celik O, Charles E, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cognard I, Cohen-Tanugi J, Cominsky LR, Conrad J, Corbet R, Cutini S, Dermer CD, Desvignes G, de Angelis A, de Luca A, de Palma F, Digel SW, Dormody M, do Couto e Silva E, Drell PS, Dubois R, Dumora D, Edmonds Y, Farnier C, Favuzzi C, Fegan SJ, Focke WB, Frailis M, Freire PC, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giebels B, Giglietto N, Giordano F, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guillemot L, Guiriec S, Hanabata Y, Harding AK, Hayashida M, Hays E, Hobbs G, Hughes RE, Jóhannesson G, Johnson AS, Johnson RP, Johnson TJ, Johnson WN, Johnston S, Kamae T, Katagiri H, Kataoka J, Kawai N, Kerr M, Knödlseder J, Kocian ML, Kramer M, Kuss M, Lande J, Latronico L, Lemoine-Goumard M, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Madejski GM, Makeev A, Manchester RN, Marelli M, Mazziotta MN, McConville W, McEnery JE, McLaughlin MA, Meurer C, Michelson PF, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nolan PL, Norris JP, Nuss E, Ohsugi T, Omodei N, Orlando E, Ormes JF, Paneque D, Panetta JH, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Piron F, Porter TA, Rainò S, Rando R, Ransom SM, Ray PS, Razzano M, Rea N, Reimer A, Reimer O, Reposeur T, Ritz S, Rochester LS, Rodriguez AY, Romani RW, Roth M, Ryde F, Sadrozinski HF, Sanchez D, Sander A, Saz Parkinson PM, Scargle JD, Schalk TL, Sgrò C, Siskind EJ, Smith DA, Smith PD, Spandre G, Spinelli P, Stappers BW, Starck JL, Striani E, Strickman MS, Suson DJ, Tajima H, Takahashi H, Tanaka T, Thayer JB, Thayer JG, Theureau G, Thompson DJ, Thorsett SE, Tibaldo L, Torres DF, Tosti G, Tramacere A, Uchiyama Y, Usher TL, Van Etten A, Vasileiou V, Venter C, Vilchez N, Vitale V, Waite AP, Wallace E, Wang P, Watters K, Webb N, Weltevrede P, Winer BL, Wood KS, Ylinen T, and Ziegler M

Abstract

Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars. The basic emission mechanism seems to be the same for MSPs and young pulsars, with the emission originating in regions far from the neutron star surface.

Published
2009
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16. Fermi observations of high-energy gamma-ray emission from GRB 080916C.

Author

Abdo AA, Ackermann M, Arimoto M, Asano K, Atwood WB, Axelsson M, Baldini L, Ballet J, Band DL, Barbiellini G, Baring MG, Bastieri D, Battelino M, Baughman BM, Bechtol K, Bellardi F, Bellazzini R, Berenji B, Bhat PN, Bissaldi E, Blandford RD, Bloom ED, Bogaert G, Bogart JR, Bonamente E, Bonnell J, Borgland AW, Bouvier A, Bregeon J, Brez A, Briggs MS, Brigida M, Bruel P, Burnett TH, Burrows D, Busetto G, Caliandro GA, Cameron RA, Caraveo PA, Casandjian JM, Ceccanti M, Cecchi C, Celotti A, Charles E, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Connaughton V, Conrad J, Costamante L, Cutini S, Deklotz M, Dermer CD, de Angelis A, de Palma F, Digel SW, Dingus BL, do Couto E Silva E, Drell PS, Dubois R, Dumora D, Edmonds Y, Evans PA, Fabiani D, Farnier C, Favuzzi C, Finke J, Fishman G, Focke WB, 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 IA, Grondin MH, Grove JE, Guillemot L, Guiriec S, Haller G, Hanabata Y, Harding AK, Hayashida M, Hays E, Hernando Morat JA, Hoover A, Hughes RE, Jóhannesson G, Johnson AS, Johnson RP, Johnson TJ, Johnson WN, Kamae T, Katagiri H, Kataoka J, Kavelaars A, Kawai N, Kelly H, Kennea J, Kerr M, Kippen RM, Knödlseder J, Kocevski D, Kocian ML, Komin N, Kouveliotou C, Kuehn F, Kuss M, Lande J, Landriu D, Larsson S, Latronico L, Lavalley C, Lee B, Lee SH, Lemoine-Goumard M, Lichti GG, Longo F, Loparco F, Lott B, Lovellette MN, Lubrano P, Madejski GM, Makeev A, Marangelli B, Mazziotta MN, McBreen S, McEnery JE, McGlynn S, Meegan C, Mészáros P, Meurer C, Michelson PF, Minuti M, Mirizzi N, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Moretti E, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Nelson D, Nolan PL, Norris JP, Nuss E, Ohno M, Ohsugi T, Okumura A, Omodei N, Orlando E, Ormes JF, Ozaki M, Paciesas WS, Paneque D, Panetta JH, Parent D, Pelassa V, Pepe M, Perri M, Pesce-Rollins M, Petrosian V, Pinchera M, Piron F, Porter TA, Preece R, Rainò S, Ramirez-Ruiz E, Rando R, Rapposelli E, Razzano M, Razzaque S, Rea N, Reimer A, Reimer O, Reposeur T, Reyes LC, Ritz S, Rochester LS, Rodriguez AY, Roth M, Ryde F, Sadrozinski HF, Sanchez D, Sander A, Saz Parkinson PM, Scargle JD, Schalk TL, Segal KN, Sgrò C, Shimokawabe T, Siskind EJ, Smith DA, Smith PD, Spandre G, Spinelli P, Stamatikos M, Starck JL, Stecker FW, Steinle H, Stephens TE, Strickman MS, Suson DJ, Tagliaferri G, Tajima H, Takahashi H, Takahashi T, Tanaka T, Tenze A, Thayer JB, Thayer JG, Thompson DJ, Tibaldo L, Torres DF, Tosti G, Tramacere A, Turri M, Tuvi S, Usher TL, van der Horst AJ, Vigiani L, Vilchez N, Vitale V, von Kienlin A, Waite AP, Williams DA, Wilson-Hodge C, Winer BL, Wood KS, Wu XF, Yamazaki R, Ylinen T, and Ziegler M

Abstract

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.

Published
2009
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17. The Fermi Gamma-Ray Space Telescope discovers the pulsar in the young galactic supernova remnant CTA 1.

Author

Abdo AA, Ackermann M, Atwood WB, Baldini L, Ballet J, Barbiellini G, Baring MG, Bastieri D, Baughman BM, Bechtol K, Bellazzini R, Berenji B, Blandford RD, Bloom ED, Bogaert G, Bonamente E, Borgland AW, Bregeon J, Brez A, Brigida M, Bruel P, Burnett TH, Caliandro GA, Cameron RA, Caraveo PA, Carlson P, Casandjian JM, Cecchi C, Charles E, Chekhtman A, Cheung CC, Chiang J, Ciprini S, Claus R, Cohen-Tanugi J, Cominsky LR, Conrad J, Cutini S, Davis DS, Dermer CD, de Angelis A, de Palma F, Digel SW, Dormody M, do Couto E Silva E, Drell PS, Dubois R, Dumora D, Edmonds Y, Farnier C, Focke WB, Fukazawa Y, Funk S, Fusco P, Gargano F, Gasparrini D, Gehrels N, Germani S, Giebels B, Giglietto N, Giordano F, Glanzman T, Godfrey G, Grenier IA, Grondin MH, Grove JE, Guillemot L, Guiriec S, Harding AK, Hartman RC, Hays E, Hughes RE, Jóhannesson G, Johnson AS, Johnson RP, Johnson TJ, Johnson WN, Kamae T, Kanai Y, Kanbach G, Katagiri H, Kawai N, Kerr M, Kishishita T, Kiziltan B, Knödlseder J, Kocian ML, Komin N, Kuehn F, Kuss M, Latronico L, Lemoine-Goumard M, Longo F, Lonjou V, Loparco F, Lott B, Lovellette MN, Lubrano P, Makeev A, Marelli M, Mazziotta MN, McEnery JE, McGlynn S, Meurer C, Michelson PF, Mineo T, Mitthumsiri W, Mizuno T, Moiseev AA, Monte C, Monzani ME, Morselli A, Moskalenko IV, Murgia S, Nakamori T, Nolan PL, Nuss E, Ohno M, Ohsugi T, Okumura A, Omodei N, Orlando E, Ormes JF, Ozaki M, Paneque D, Panetta JH, Parent D, Pelassa V, Pepe M, Pesce-Rollins M, Piano G, Pieri L, Piron F, Porter TA, Rainò S, Rando R, Ray PS, Razzano M, Reimer A, Reimer O, Reposeur T, Ritz S, Rochester LS, Rodriguez AY, Romani RW, Roth M, Ryde F, Sadrozinski HF, Sanchez D, Sander A, Parkinson PM, Schalk TL, Sellerholm A, Sgrò C, Siskind EJ, Smith DA, Smith PD, Spandre G, Spinelli P, Starck JL, Strickman MS, Suson DJ, Tajima H, Takahashi H, Takahashi T, Tanaka T, Thayer JB, Thayer JG, Thompson DJ, Thorsett SE, Tibaldo L, Torres DF, Tosti G, Tramacere A, Usher TL, Van Etten A, Vilchez N, Vitale V, Wang P, Watters K, Winer BL, Wood KS, Yasuda H, Ylinen T, and Ziegler M

Abstract

Energetic young pulsars and expanding blast waves [supernova remnants (SNRs)] are the most visible remains after massive stars, ending their lives, explode in core-collapse supernovae. The Fermi Gamma-Ray Space Telescope has unveiled a radio quiet pulsar located near the center of the compact synchrotron nebula inside the supernova remnant CTA 1. The pulsar, discovered through its gamma-ray pulsations, has a period of 316.86 milliseconds and a period derivative of 3.614 x 10(-13) seconds per second. Its characteristic age of 10(4) years is comparable to that estimated for the SNR. We speculate that most unidentified Galactic gamma-ray sources associated with star-forming regions and SNRs are such young pulsars.

Published
2008
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