Data di Pubblicazione:
2009
Abstract:
We report the Fermi LargeArea Telescope (LAT) discovery of high-energy (MeV/GeV) γ -ray emission positionally
consistent with the center of the radio galaxy M87, at a source significance of over 10σ in 10 months of all-sky
survey data. Following the detections of Cen A and Per A, this makesM87 the third radio galaxy seen with the LAT.
The faint point-like γ -ray source has a >100 MeV flux of 2.45 (±0.63) × 10−8 photons cm−2 s−1 (photon index =
2.26 ± 0.13) with no significant variability detected within the LAT observation. This flux is comparable with the
previous EGRET upper limit (<2.18×10−8 photons cm−2 s−1, 2σ), thus there is no evidence for a significant MeV/
GeV flare on decade timescales.Contemporaneous Chandra andVery Long BaselineArray data indicate lowactivity
in the unresolvedX-ray and radio core relative to previous observations, suggesting M87 is in a quiescent overall level
over the first year of Fermi-LAT observations. The LAT γ -ray spectrum is modeled as synchrotron self-Compton
(SSC) emission from the electron population producing the radio-to-X-ray emission in the core. The resultant SSC
spectrum extrapolates smoothly from the LAT band to the historical-minimum TeV emission. Alternative models
for the core and possible contributions from the kiloparsec-scale jet in M87 are considered, and cannot be excluded.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
galaxies: active , galaxies: individual (M87) , galaxies: jets , gamma rays: observations , radiation
mechanisms: non-thermal
Elenco autori:
A. A. Abdo;M. Ackermann;M. Ajello;W. B. Atwood;M. Axelsson;L. Baldini;J. Ballet;G. Barbiellini;D. Bastieri;K. Bechtol;R. Bellazzini;B. Berenji;R. D. Blandford;E. D. Bloom;E. Bonamente;A. W. Borgland;J. Bregeon;A. Brez;M. Brigida;P. Bruel;T. H. Burnett;G. A. Caliandro;R. A. Cameron;A. Cannon;P. A. Caraveo;J. M. Casandjian;E. Cavazzuti;C. Cecchi;Ö. Çelik;E. Charles;C. C. Cheung;J. Chiang;S. Ciprini;R. Claus;J. Cohen-Tanugi;S. Colafrancesco;J. Conrad;L. Costamante;S. Cutini;D. S. Davis;C. D. Dermer;A. de Angelis;F. de Palma;S. W. Digel;D. Donato;E. do Couto e Silva;P. S. Drell;R. Dubois;D. Dumora;Y. Edmonds;C. Farnier;C. Favuzzi;S. J. Fegan;J. Finke;W. B. Focke;P. Fortin;M. Frailis;Y. Fukazawa;S. Funk;P. Fusco;F. Gargano;D. Gasparrini;N. Gehrels;M. Georganopoulos;S. Germani;B. Giebels;N. Giglietto;P. Giommi;F. Giordano;M. Giroletti;T. Glanzman;G. Godfrey;I. A. Grenier;M.-H. Grondin;J. E. Grove;L. Guillemot;S. Guiriec;Y. Hanabata;A. K. Harding;M. Hayashida;E. Hays;D. Horan;G. Jóhannesson;A. S. Johnson;R. P. Johnson;T. J. Johnson;W. N. Johnson;T. Kamae;H. Katagiri;J. Kataoka;N. Kawai;M. Kerr;J. Knödlseder;M. L. Kocian;M. Kuss;J. Lande;L. Latronico;M. Lemoine-Goumard;F. Longo;F. Loparco;B. Lott;M. N. Lovellette;P. Lubrano;G. M. Madejski;A. Makeev;M. N. Mazziotta;W. McConville;J. E. McEnery;C. Meurer;P. F. Michelson;W. Mitthumsiri;T. Mizuno;A. A. Moiseev;C. Monte;M. E. Monzani;A. Morselli;I. V. Moskalenko;S. Murgia;P. L. Nolan;J. P. Norris;E. Nuss;T. Ohsugi;N. Omodei;E. Orlando;J. F. Ormes;M. Ozaki;D. Paneque;J. H. Panetta;D. Parent;V. Pelassa;M. Pepe;M. Pesce-Rollins;F. Piron;T. A. Porter;S. Rainò;R. Rando;M. Razzano;A. Reimer;O. Reimer;T. Reposeur;S. Ritz;L. S. Rochester;A. Y. Rodriguez;R. W. Romani;M. Roth;F. Ryde;H. F.-W. Sadrozinski;R. Sambruna;D. Sanchez;A. Sander;P. M. Saz Parkinson;J. D. Scargle;C. Sgrò;M. S. Shaw;D. A. Smith;P. D. Smith;G. Spandre;P. Spinelli;M. S. Strickman;D. J. Suson;H. Tajima;H. Takahashi;T. Tanaka;G. B. Taylor;J. B. Thayer;D. J. Thompson;L. Tibaldo;D. F. Torres;G. Tosti;A. Tramacere;Y. Uchiyama;T. L. Usher;V. Vasileiou;N. Vilchez;A. P. Waite;P. Wang;B. L. Winer;K. S. Wood;T. Ylinen;M. Ziegler;D. E. Harris;F. Massaro;Ł. Stawarz
Link alla scheda completa:
Pubblicato in: