Gamma-ray light curves and variability of bright fermi-detected blazars

A. A. Abdo; M. Ackermann; M. Ajello; E. Antolini; 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; A. Bouvier; J. Bregeon; A. Brez; M. Brigida; P. Bruel; R. Buehler; T. H. Burnett; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; S. Carrigan; J. M. Casandjian; E. Cavazzuti; C. Cecchi; Ö Çelik; A. Chekhtman; C. C. Cheung; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; L. R. Cominsky; J. Conrad; L. Costamante; S. Cutini; C. D. Dermer; A. De Angelis; F. De Palma; E. Do Couto E Silva; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; S. J. Fegan; W. B. Focke; P. Fortin; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; B. Giebels; N. Giglietto; P. Giommi; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M. H. Grondin; J. E. Grove; S. Guiriec; D. Hadasch; M. Hayashida; E. Hays; S. E. Healey; D. Horan; R. E. Hughes; R. Itoh; G. Jóhannesson; A. S. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; J. Kataoka; N. Kawai; J. Knödlseder; M. Kuss; J. Lande; S. Larsson; L. Latronico; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; G. M. Madejski; A. Makeev; E. Massaro; M. N. Mazziotta; J. E. McEnery; P. F. Michelson; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; M. Mueller; S. Murgia; P. L. Nolan; J. P. Norris; E. Nuss; M. Ohno; T. Ohsugi; N. Omodei; E. Orlando; J. F. Ormes; M. Ozaki; 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; S. Ritz; A. Y. Rodriguez; R. W. Romani; M. Roth; F. Ryde; H. F.W. Sadrozinski; A. Sander; J. D. Scargle; C. Sgrò; M. S. Shaw; P. D. Smith; G. Spandre; P. Spinelli; J. L. Starck; M. S. Strickman; D. J. Suson; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; L. Tibaldo; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; V. Vasileiou; N. Vilchez; V. Vitale; A. P. Waite; E. Wallace; P. Wang; B. L. Winer; K. S. Wood; Z. Yang; T. Ylinen; M. Ziegler

doi:10.1088/0004-637X/722/1/520

Gamma-ray light curves and variability of bright fermi-detected blazars

A. A. Abdo
, M. Ackermann
, M. Ajello
, E. Antolini
, 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
, A. Bouvier
, J. Bregeon
, A. Brez
, M. Brigida
, P. Bruel

R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, S. Carrigan, J. M. Casandjian, E. Cavazzuti, C. Cecchi, Ö Çelik, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. De Angelis, F. De Palma, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, S. J. Fegan, W. B. Focke, P. Fortin, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, S. E. Healey, D. Horan, R. E. Hughes, R. Itoh, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, N. Kawai, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, E. Massaro, M. N. Mazziotta, J. E. McEnery, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, M. Mueller, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, 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, S. Ritz, A. Y. Rodriguez, R. W. Romani, M. Roth, F. Ryde, H. F.W. Sadrozinski, A. Sander, J. D. Scargle, C. Sgrò, M. S. Shaw, P. D. Smith, G. Spandre, P. Spinelli, J. L. Starck, M. S. Strickman, D. J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, V. Vasileiou, N. Vilchez, V. Vitale, A. P. Waite, E. Wallace, P. Wang, B. L. Winer, K. S. Wood, Z. Yang, T. Ylinen, M. Ziegler

Naval Research Laboratory
National Research Council
Stanford University
INFN Sezione di Perugia
University of Perugia
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
Universite Paris-Saclay
INFN Sezione di Trieste
University of Trieste
INFN
University of Padova
Politecnico di Bari
INFN Sezione di Bari
University of Washington
University of São Paulo
INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan
Science and Research Directorate
NASA Goddard Space Flight Center
Biochemical and Environmental Engineering
George Mason University
Laboratoire Univers et Particules de Montpellier
Sonoma State University
Stockholm University
Oskar Klein Centre
Sezione di Roma
UMR 5797
Univ. Bordeaux
INAF-Trieste
Hiroshima University
Center for Space Plasma and Aeronomic Research
Pompeu Fabra University (UPF)
The Ohio State University
Waseda University
Tokyo Institute of Technology
RIKEN (The Institute of Physical and Chemical Research)
Centre national de la recherche scientifique
University of Rome
University of Maryland
University of Denver
ISAS/JAXA
Max Planck Institut für Extraterrestrische Physik
Medical University of Innsbruck
University of California at Santa Cruz
KTH Royal Institute of Technology
NASA Ames Research Center
Purdue University Northwest
Consorzio Interuniversitario per la Fisica Spaziale (CIFS)
University of Geneva
University of Rome “Tor Vergata”
University of Kalmar

Research output: Contribution to journal › Article › peer-review

355 Citations (Scopus)

Abstract

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.

Original language	English
Pages (from-to)	520-542
Number of pages	23
Journal	Astrophysical Journal
Volume	722
Issue number	1
DOIs	https://doi.org/10.1088/0004-637X/722/1/520
Publication status	Published - 10 Oct 2010

Keywords

BL Lacertae objects: General
Gamma rays: Galaxies
Gamma rays: General
Methods: Data analysis
Methods: Statistical
Quasars: General

Access to Document

10.1088/0004-637X/722/1/520

Cite this

Abdo, A. A., Ackermann, M., Ajello, M., Antolini, E., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bouvier, A., Bregeon, J., Brez, A., Brigida, M., ... Ziegler, M. (2010). Gamma-ray light curves and variability of bright fermi-detected blazars. Astrophysical Journal, 722(1), 520-542. https://doi.org/10.1088/0004-637X/722/1/520

@article{1dec9ec5ddb64994a341f9c9e60c7a38,

title = "Gamma-ray light curves and variability of bright fermi-detected blazars",

abstract = "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/fα 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.",

keywords = "BL Lacertae objects: General, Gamma rays: Galaxies, Gamma rays: General, Methods: Data analysis, Methods: Statistical, Quasars: General",

author = "Abdo, \{A. A.\} and M. Ackermann and M. Ajello and E. Antolini and L. Baldini and J. Ballet and G. Barbiellini and D. Bastieri and K. Bechtol and R. Bellazzini and B. Berenji and Blandford, \{R. D.\} and Bloom, \{E. D.\} and E. Bonamente and Borgland, \{A. W.\} and A. Bouvier and J. Bregeon and A. Brez and M. Brigida and P. Bruel and R. Buehler and Burnett, \{T. H.\} and S. Buson and Caliandro, \{G. A.\} and Cameron, \{R. A.\} and Caraveo, \{P. A.\} and S. Carrigan and Casandjian, \{J. M.\} and E. Cavazzuti and C. Cecchi and {\"O} {\c C}elik and A. Chekhtman and Cheung, \{C. C.\} and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and Cominsky, \{L. R.\} and J. Conrad and L. Costamante and S. Cutini and Dermer, \{C. D.\} and \{De Angelis\}, A. and \{De Palma\}, F. and \{Do Couto E Silva\}, E. and Drell, \{P. S.\} and R. Dubois and D. Dumora and C. Farnier and C. Favuzzi and Fegan, \{S. J.\} and Focke, \{W. B.\} and P. Fortin and M. Frailis and Y. Fukazawa and S. Funk and P. Fusco and F. Gargano and D. Gasparrini and N. Gehrels and S. Germani and B. Giebels and N. Giglietto and P. Giommi and F. Giordano and T. Glanzman and G. Godfrey and Grenier, \{I. A.\} and Grondin, \{M. H.\} and Grove, \{J. E.\} and S. Guiriec and D. Hadasch and M. Hayashida and E. Hays and Healey, \{S. E.\} and D. Horan and Hughes, \{R. E.\} and R. Itoh and G. J{\'o}hannesson and Johnson, \{A. S.\} and Johnson, \{W. N.\} and T. Kamae and H. Katagiri and J. Kataoka and N. Kawai and J. Kn{\"o}dlseder and M. Kuss and J. Lande and S. Larsson and L. Latronico and M. Lemoine-Goumard and F. Longo and F. Loparco and B. Lott and Lovellette, \{M. N.\} and P. Lubrano and Madejski, \{G. M.\} and A. Makeev and E. Massaro and Mazziotta, \{M. N.\} and McEnery, \{J. E.\} and Michelson, \{P. F.\} and W. Mitthumsiri and T. Mizuno and Moiseev, \{A. A.\} and C. Monte and Monzani, \{M. E.\} and A. Morselli and Moskalenko, \{I. V.\} and M. Mueller and S. Murgia and Nolan, \{P. L.\} and Norris, \{J. P.\} and E. Nuss and M. Ohno and T. Ohsugi and N. Omodei and E. Orlando and Ormes, \{J. F.\} and M. Ozaki and Panetta, \{J. H.\} and D. Parent and V. Pelassa and M. Pepe and M. Pesce-Rollins and F. Piron and Porter, \{T. A.\} and S. Rain{\`o} and R. Rando and M. Razzano and A. Reimer and O. Reimer and S. Ritz and Rodriguez, \{A. Y.\} and Romani, \{R. W.\} and M. Roth and F. Ryde and Sadrozinski, \{H. F.W.\} and A. Sander and Scargle, \{J. D.\} and C. Sgr{\`o} and Shaw, \{M. S.\} and Smith, \{P. D.\} and G. Spandre and P. Spinelli and Starck, \{J. L.\} and Strickman, \{M. S.\} and Suson, \{D. J.\} and H. Takahashi and T. Takahashi and T. Tanaka and Thayer, \{J. B.\} and Thayer, \{J. G.\} and Thompson, \{D. J.\} and L. Tibaldo and Torres, \{D. F.\} and G. Tosti and A. Tramacere and Y. Uchiyama and Usher, \{T. L.\} and V. Vasileiou and N. Vilchez and V. Vitale and Waite, \{A. P.\} and E. Wallace and P. Wang and Winer, \{B. L.\} and Wood, \{K. S.\} and Z. Yang and T. Ylinen and M. Ziegler",

year = "2010",

month = oct,

day = "10",

doi = "10.1088/0004-637X/722/1/520",

language = "English",

volume = "722",

pages = "520--542",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "1",

}

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, Çelik, Ö, 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, Do Couto E Silva, E, 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, Jóhannesson, G, Johnson, AS, Johnson, WN, Kamae, T, Katagiri, H, Kataoka, J, Kawai, N, Knödlseder, 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, Rainò, 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, Sgrò, 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 2010, 'Gamma-ray light curves and variability of bright fermi-detected blazars', Astrophysical Journal, vol. 722, no. 1, pp. 520-542. https://doi.org/10.1088/0004-637X/722/1/520

TY - JOUR

T1 - Gamma-ray light curves and variability of bright fermi-detected blazars

AU - Abdo, A. A.

AU - Ackermann, M.

AU - Ajello, M.

AU - Antolini, E.

AU - Baldini, L.

AU - Ballet, J.

AU - Barbiellini, G.

AU - Bastieri, D.

AU - Bechtol, K.

AU - Bellazzini, R.

AU - Berenji, B.

AU - Blandford, R. D.

AU - Bloom, E. D.

AU - Bonamente, E.

AU - Borgland, A. W.

AU - Bouvier, A.

AU - Bregeon, J.

AU - Brez, A.

AU - Brigida, M.

AU - Bruel, P.

AU - Buehler, R.

AU - Burnett, T. H.

AU - Buson, S.

AU - Caliandro, G. A.

AU - Cameron, R. A.

AU - Caraveo, P. A.

AU - Carrigan, S.

AU - Casandjian, J. M.

AU - Cavazzuti, E.

AU - Cecchi, C.

AU - Çelik, Ö

AU - Chekhtman, A.

AU - Cheung, C. C.

AU - Chiang, J.

AU - Ciprini, S.

AU - Claus, R.

AU - Cohen-Tanugi, J.

AU - Cominsky, L. R.

AU - Conrad, J.

AU - Costamante, L.

AU - Cutini, S.

AU - Dermer, C. D.

AU - De Angelis, A.

AU - De Palma, F.

AU - Do Couto E Silva, E.

AU - Drell, P. S.

AU - Dubois, R.

AU - Dumora, D.

AU - Farnier, C.

AU - Favuzzi, C.

AU - Fegan, S. J.

AU - Focke, W. B.

AU - Fortin, P.

AU - Frailis, M.

AU - Fukazawa, Y.

AU - Funk, S.

AU - Fusco, P.

AU - Gargano, F.

AU - Gasparrini, D.

AU - Gehrels, N.

AU - Germani, S.

AU - Giebels, B.

AU - Giglietto, N.

AU - Giommi, P.

AU - Giordano, F.

AU - Glanzman, T.

AU - Godfrey, G.

AU - Grenier, I. A.

AU - Grondin, M. H.

AU - Grove, J. E.

AU - Guiriec, S.

AU - Hadasch, D.

AU - Hayashida, M.

AU - Hays, E.

AU - Healey, S. E.

AU - Horan, D.

AU - Hughes, R. E.

AU - Itoh, R.

AU - Jóhannesson, G.

AU - Johnson, A. S.

AU - Johnson, W. N.

AU - Kamae, T.

AU - Katagiri, H.

AU - Kataoka, J.

AU - Kawai, N.

AU - Knödlseder, J.

AU - Kuss, M.

AU - Lande, J.

AU - Larsson, S.

AU - Latronico, L.

AU - Lemoine-Goumard, M.

AU - Longo, F.

AU - Loparco, F.

AU - Lott, B.

AU - Lovellette, M. N.

AU - Lubrano, P.

AU - Madejski, G. M.

AU - Makeev, A.

AU - Massaro, E.

AU - Mazziotta, M. N.

AU - McEnery, J. E.

AU - Michelson, P. F.

AU - Mitthumsiri, W.

AU - Mizuno, T.

AU - Moiseev, A. A.

AU - Monte, C.

AU - Monzani, M. E.

AU - Morselli, A.

AU - Moskalenko, I. V.

AU - Mueller, M.

AU - Murgia, S.

AU - Nolan, P. L.

AU - Norris, J. P.

AU - Nuss, E.

AU - Ohno, M.

AU - Ohsugi, T.

AU - Omodei, N.

AU - Orlando, E.

AU - Ormes, J. F.

AU - Ozaki, M.

AU - Panetta, J. H.

AU - Parent, D.

AU - Pelassa, V.

AU - Pepe, M.

AU - Pesce-Rollins, M.

AU - Piron, F.

AU - Porter, T. A.

AU - Rainò, S.

AU - Rando, R.

AU - Razzano, M.

AU - Reimer, A.

AU - Reimer, O.

AU - Ritz, S.

AU - Rodriguez, A. Y.

AU - Romani, R. W.

AU - Roth, M.

AU - Ryde, F.

AU - Sadrozinski, H. F.W.

AU - Sander, A.

AU - Scargle, J. D.

AU - Sgrò, C.

AU - Shaw, M. S.

AU - Smith, P. D.

AU - Spandre, G.

AU - Spinelli, P.

AU - Starck, J. L.

AU - Strickman, M. S.

AU - Suson, D. J.

AU - Takahashi, H.

AU - Takahashi, T.

AU - Tanaka, T.

AU - Thayer, J. B.

AU - Thayer, J. G.

AU - Thompson, D. J.

AU - Tibaldo, L.

AU - Torres, D. F.

AU - Tosti, G.

AU - Tramacere, A.

AU - Uchiyama, Y.

AU - Usher, T. L.

AU - Vasileiou, V.

AU - Vilchez, N.

AU - Vitale, V.

AU - Waite, A. P.

AU - Wallace, E.

AU - Wang, P.

AU - Winer, B. L.

AU - Wood, K. S.

AU - Yang, Z.

AU - Ylinen, T.

AU - Ziegler, M.

PY - 2010/10/10

Y1 - 2010/10/10

N2 - 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/fα 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.

AB - 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/fα 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.

KW - BL Lacertae objects: General

KW - Gamma rays: Galaxies

KW - Gamma rays: General

KW - Methods: Data analysis

KW - Methods: Statistical

KW - Quasars: General

U2 - 10.1088/0004-637X/722/1/520

DO - 10.1088/0004-637X/722/1/520

M3 - Article

AN - SCOPUS:78149297526

SN - 0004-637X

VL - 722

SP - 520

EP - 542

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1

ER -

Gamma-ray light curves and variability of bright fermi-detected blazars

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