This paper presents light curves as well as the first systematic characterization of variability of the 106 objects in the high-confidence Fermi Large Area Telescope Bright AGN Sample (LBAS). Weekly light curves of this sample, obtained during the first 11 months of the Fermi survey (2008 August 4-2009 July 4), are tested for variability and their properties are quantified through autocorrelation function and structure function analysis. For the brightest sources, 3 or 4 day binned light curves are extracted in order to determine power density spectra (PDSs) and to fit the temporal structure of major flares. More than 50% of the sources are found to be variable with high significance, where high states do not exceed 1/4 of the total observation range. Variation amplitudes are larger for flat spectrum radio quasars and low/intermediate synchrotron frequency peaked BL Lac objects. Autocorrelation timescales derived from weekly light curves vary from four to a dozen of weeks. Variable sources of the sample have weekly and 3-4 day bin light curves that can be described by 1/f α PDS, and show two kinds of gamma-ray variability: (1) rather constant baseline with sporadic flaring activity characterized by flatter PDS slopes resembling flickering and red noise with occasional intermittence and (2)—measured for a few blazars showing strong activity—complex and structured temporal profiles characterized by long-term memory and steeper PDS slopes, reflecting a random walk underlying mechanism. The average slope of the PDS of the brightest 22 FSRQs and of the 6 brightest BL Lacs is 1.5 and 1.7, respectively. The study of temporal profiles of well-resolved flares observed in the 10 brightest LBAS sources shows that they generally have symmetric profiles and that their total duration vary between 10 and 100 days. Results presented here can assist in source class recognition for unidentified sources and can serve as reference for more detailed analysis of the brightest gamma-ray blazars.
|Autori:||Abdo AA; Ackermann M; Ajello M; Antolini E; Baldini L; Ballet J; Barbiellini G; Bastieri D; Bechtol K; Bellazzini R; Berenji B; Blandford RD; Bloom ED; Bonamente E; Borgland AW; Bouvier A; Bregeon J; Brez A; Brigida M; Bruel P; Buehler R; Burnett TH; Buson S; Caliandro GA; Cameron RA; Caraveo PA; Carrigan S; Casandjian JM; Cavazzuti E; Cecchi C; Celik O; Chekhtman A; Cheung CC; Chiang J; Ciprini S; Claus R; Cohen-Tanugi J; Cominsky LR; Conrad J; Costamante L; Cutini S; Dermer CD; de Angelis A; de Palma F; Silva EDE; Drell PS; Dubois R; Dumora D; 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; Giebels B; Giglietto N; Giommi P; Giordano F; Glanzman T; Godfrey G; Grenier IA; Grondin MH; Grove JE; Guiriec S; Hadasch D; Hayashida M; Hays E; Healey SE; Horan D; Hughes RE; Itoh R; Johannesson G; Johnson AS; Johnson WN; Kamae T; Katagiri H; Kataoka J; Kawai N; Knodlseder J; Kuss M; Lande J; Larsson S; Latronico L; Lemoine-Goumard M; Longo F; Loparco F; Lott B; Lovellette MN; Lubrano P; Madejski GM; Makeev A; Massaro E; Mazziotta MN; McEnery JE; Michelson PF; Mitthumsiri W; Mizuno T; Moiseev AA; Monte C; Monzani ME; Morselli A; Moskalenko IV; Mueller M; Murgia S; Nolan PL; Norris JP; Nuss E; Ohno M; Ohsugi T; Omodei N; Orlando E; Ormes JF; Ozaki M; Panetta JH; Parent D; Pelassa V; Pepe M; Pesce-Rollins M; Piron F; Porter TA; Raino S; Rando R; Razzano M; Reimer A; Reimer O; Ritz S; Rodriguez AY; Romani RW; Roth M; Ryde F; Sadrozinski HFW; Sander A; Scargle JD; Sgro C; Shaw MS; Smith PD; Spandre G; Spinelli P; Starck JL; Strickman MS; Suson DJ; 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; Yang Z; Ylinen T; Ziegler M|
|Titolo:||GAMMA-RAY LIGHT CURVES AND VARIABILITY OF BRIGHT FERMI-DETECTED BLAZARS|
|Anno del prodotto:||2010|
|Digital Object Identifier (DOI):||10.1088/0004-637X/722/1/520|
|Appare nelle tipologie:||1.1 Articolo in rivista|