Expériences et Modélisation en Astroparticules et Cosmologie
(625) Production(s)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90

H.E.S.S. upper limit on the very high energy gamma-ray emission from the globular cluster 47 Tucanae

Auteur(s): Aharonian F., Bazer-Bachi A.R., Becherini Y., Boisson C., Borrel V., Brion E., Brun P., Boutelier T., Charbonnier A., Chounet L.-M., Coignet G., Degrange B., Djannati-Ataï A., Dubois F., Dubus G., Espigat P., Farnier C., Feinstein F., Fiasson A., Fontaine G., Gallant Y., Gérard L., Giebels B., Glicenstein J.F., Goret P., Henri G., Jacholkowska A., Kh´elifi B., Marcowith A., Vasileiadis G.

(Article) Publié: Astronomy & Astrophysics, vol. 499 p.273-277 (2009)
Texte intégral en Openaccess :

Measurement of the Cosmic Ray e(+)+e(-) Spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope

Auteur(s): Abdo A.A., Ackermann M., Ajello M., B. Atwood W., Axelsson M., Baldini L., Ballet J., Bogaert G., Bruel P., Casandjian J.M., Cohen-Tanugi J., Dumora D., Farnier C., Giebels B., Grenier I.A., Grondin M.-H., Guillemot L., Guiriec Sylvain, Knödlseder J., Lemoine-Goumard M., Lott B., Nuss E., Parent D., Pelassa V., Piron F., Reposeur T., Sanchez D., Smith D. A., Starck J.-L., Vilchez N.

(Article) Publié: Physical Review Letters, vol. 102 p.181101 (2009)
Texte intégral en Openaccess :

Search for diffuse gamma rays from the Galactic anticentre region above 100 GeV with CELESTE

Auteur(s): Britto Richard, Jacholkowska Agnieszka, Piron F., Brion E., Gordo J.B., Debiais G., Fabre B., Lavalle J., Muenz F., Nuss E., Rannot R.C., Reposeur T.

(Article) Publié: Astronomy & Astrophysics, vol. 498 p.L25-L28 (2009)

Early Fermi Gamma-ray Space Telescope Observations of the Quasar 3C 454.3

Auteur(s): Abdo A.A., Ackermann M., Ajello M., B. Atwood W., Axelsson M., Baldini L., Ballet J., Barbiellini G., Bruel P., M. Casandjian J., Cohen-Tanugi J., Dumora D., Farnier C., Giebels B., A. Grenier I., Grondin M.-H., Guillemot L., Knodlseder J., Lemoine-Goumard M., Lott B., Nuss E., Parent D., Pelassa V., Piron F., Reposeur T., Rahoui F., Sanchez D., A. Smith D., Starck J.-L., Vilchez N.

(Article) Publié: The Astrophysical Journal / The Astrophysical Journal Letters, vol. 699 p.817-823 (2009)
Texte intégral en Openaccess :

Ref HAL: in2p3-00380233_v1
Ref Arxiv: 0904.4280
DOI: 10.1088/0004-637X/699/1/817
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
102 citations
Résumé:

This is the first report of Fermi Gamma-ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope (LAT), covering 2008 July 7 - October 6, indicate strong, highly variable gamma-ray emission with an average flux of ~3 x 10^{-6} photons cm^{-2} s^{-1}, for energies above 100 MeV. The gamma-ray flux is variable, with strong, distinct, symmetrically-shaped flares for which the flux increases by a factor of several on a time scale of about three days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair-production implies relativistic beaming with Doppler factor delta > 8, consistent with the values inferred from VLBI observations of superluminal expansion (delta ~ 25). The observed gamma-ray spectrum is not consistent with a simple power-law, but instead steepens strongly above ~2 GeV, and is well described by a broken power-law with photon indices of ~2.3 and ~3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2 GeV could be due to gamma-ray absorption via photon-photon pair production on the soft X-ray photon field of the host AGN, but such an interpretation would require the dissipation region to be located very close (less than 100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

Commentaires: Accepted by the Astrophysical Journal; corresponding authors: Greg Madejski (madejski@slac.stanford.edu) and Benoit Lott (lott@cenbg.in2p3.fr)

Pulsed Gamma-rays from the millisecond pulsar J0030+0451 with the Fermi Large Area Telescope

Auteur(s): Abdo A.A., Ackermann M., B. Atwood W., Axelsson M., Ballet J., Bruel P., M. Casandjian J., Cognard I., Cohen-Tanugi J., Dumora D., Farnier C., Giebels B., A. Grenier I., Grondin M.-H., Guillemot L., Guiriec Sylvain, Knodlseder J., Komin Nukri, Lemoine-Goumard M., Lott B., Nuss E., Pancrazi B., Parent D., Piron F., Reposeur T., Sanchez D., A. Smith D., Starck J.-L., Theureau G., Vilchez N.

(Article) Publié: The Astrophysical Journal / The Astrophysical Journal Letters, vol. 699 p.1171-1177 (2009)
Texte intégral en Openaccess :

The On-orbit Calibrations for the Fermi Large Area Telescope

Auteur(s): A. Abdo A., Ballet J., Bédérède D., Bogaert G., Bourgeois P., Bruel P., M. Casandjian J., Chipaux R., Cohen-Tanugi J., Dumora D., Farnier C., Ferreira O., Fleury P., Giebels B., A. Grenier I., Grondin M.-H., Guillemot L., Guiriec Sylvain, Knodlseder J., Lavalley-fouquet Claudia, Lemoine-Goumard M., Lott B., Nuss E., Parent D., Pelassa V., Piron F., Reposeur T., Sanchez D., A. Smith D., Starck J.-L.

(Article) Publié: Astroparticle Physics, vol. 32 p.193-219 (2009)
Texte intégral en Openaccess :

Fermi Large Area Telescope Bright Gamma-ray Source List

Auteur(s): Abdo A. A., Ackermann M., Ajello M., B. Atwood W., Axelsson M., Ballet J., Bruel P., M. Casandjian J., Cohen-Tanugi J., Dumora D., Farnier C., J. Fegan S., Giebels B., A. Grenier I., Grondin M.-H., Guillemot L., Guiriec Sylvain, Horan D., Knodlseder J., Komin Nukri, Lemoine-Goumard M., Lott B., Nuss E., Parent D., Piron F., Poupard L., Reposeur T., Sanchez D., A. Smith D., Starck J.-L.

(Article) Publié: The Astrophysical Journal Supplement Series, vol. 183/1 p.46-66 (2009)
Texte intégral en Openaccess :

Recherche approfondie

Expériences et Modélisation en Astroparticules et Cosmologie
(625) Production(s)

Recherche approfondie

Expériences et Modélisation en Astroparticules et Cosmologie(625) Production(s)

Expériences et Modélisation en Astroparticules et Cosmologie
(625) Production(s)