The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies

J. Becerra Gonz\'alez (8) W. Bednarek (9) K. Berger (8) E. Bernardini (10) A. Biland (11) O. Blanch (1) R. K. Bock (6) S. Bonnefoy (7) G. Bonnoli (3) F. Borracci (6) T. Bretz (12 25) E. Carmona (13) A. Carosi (3) D. Carreto Fidalgo (12) P. Colin (6) E. Colombo (8) J. L. Contreras (7) J. Cortina (1) S. Covino (3) P. Da Vela (4) F. Dazzi (2) A. De Angelis (2) G. De Caneva (10) B. De Lotto (2) C. Delgado Mendez (13) M. Doert (14) A. Dom\'inguez (15 26) D. Dominis Prester (5) D. Dorner (12) M. Doro (16) S. Einecke (14) D. Eisenacher (12) D. Elsaesser (12) E. Farina (17) D. Ferenc (5) M. V. Fonseca (7) L. Font (18) K. Frantzen (14) C. Fruck (6) R. J. Garc\'ia L\'opez (8) M. Garczarczyk (10) D. Garrido Terrats (18) M. Gaug (18) G. Giavitto (1) N. Godinovi\'c (5) A. Gonz\'alez Mu\ noz (1) S. R. Gozzini (10) A. Hadamek (14) D. Hadasch (19) A. Herrero (8) D. Hildebrand (11) J. Hose (6) D. Hrupec (5) W. Idec (9) V. Kadenius (20) H. Kellermann (6) M. L. Knoetig (11) J. Krause (6) J. 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Schultz (16) T. Schweizer (6) S. N. Shore (24) A. Sillanp\"a\"a (20) J. Sitarek (1) I. Snidaric (5) D. Sobczynska (9) F. Spanier (12) V. Stamatescu (1) A. Stamerra (3) T. Steinbring (12) J. Storz (12) S. Sun (6) T. Suri\'c (5) L. Takalo (20) F. Tavecchio (3) P. Temnikov (22) T. Terzi\'c (5) D. Tescaro (8) M. Teshima (6) J. Thaele (14) O. Tibolla (12) D. F. Torres (19) T. Toyama (6) A. Treves (17) M. Uellenbeck (14) P. Vogler (11) R. M. Wagner (6 30) F. Zandanel (15 31) R. Zanin (23) VERITAS collaboration: S. Archambault (33) B. Behera (10) M. Beilicke (35) W. Benbow (36) R. Bird (37) J. H. Buckley (35) V. Bugaev (35) M. Cerruti (36) X. Chen (38 34) L. Ciupik (39) E. Collins-Hughes (37) W. Cui (40) J. Dumm (41) J. D. Eisch (42) A. Falcone (43) S. Federici (34 38) Q. Feng (40) J. P. Finley (40) H. Fleischhack (10) P. Fortin (59) L. Fortson (41) A. Furniss (44) S. Griffin (33) S. T. Griffiths (45) J. Grube (39) G. Gyuk (39) D. Hanna (33) J. Holder (46) G. Hughes (10) T. B. Humensky (47) C. A. Johnson (44) P. Kaaret (45) M. Kertzman (48) Y. Khassen (37) D. Kieda (49) H. Krawczynski (35) F. Krennrich (42) S. Kumar (46) M. J. Lang (50) G. Maier (10) S. McArthur (51) K. Meagher (52) P. Moriarty (53 50) R. Mukherjee (54) R. A. Ong (55) A. N. Otte (52) N. Park (51) A. Pichel (56) M. Pohl (38 A. Popkow (55) H. Prokoph (10) J. Quinn (37) K. Ragan (33) J. Rajotte (33) P. T. Reynolds (57) G. T. Richards (52) E. Roache (36) A. C. Rovero (56) G. H. Sembroski (40) K. Shahinyan (41) D. Staszak (33) I. Telezhinsky (38 M. Theiling (40) J. V. Tucci (40) J. Tyler (33) A. Varlotta (40) S. P. Wakely (51) T. C. Weekes (36) A. Weinstein (42) R. Welsing (10) A. Wilhelm (38 D. A. Williams (44) B. Zitzer (58) External Collaborators: M. Villata (60) C. Raiteri (60) H. D. Aller (61) M. F. Aller (61) W. P. Chen (62) B. Jordan (63) E. Koptelova (62 64) O. M. Kurtanidze (65 66) A. L\"ahteenm\"aki (67 68) B. McBreen (69) V. M. Larionov (70 71 72) C. S. Lin (62) M. G. Nikolashvili (65) E. Angelakis (73) M. Capalbi (86) A. Carrami\ nana (75) L. Carrasco (75) P. Cassaro (76) A. Cesarini (77) L. Fuhrmann (73) M. Giroletti (91) T. Hovatta (78) T. P. Krichbaum (73) H. A. Krimm (79 80) W. Max-Moerbeck (78) J. W. Moody (83) G. Maccaferri (84) Y. Mori (85) I. Nestoras (73) A. Orlati (84) C. Pace (81) R. Pearson (83) M. Perri (3 86) A.C.S. Readhead (78) J.L. Richards (87) A. C. Sadun (88) T. Sakamoto (89) J. Tammi (67 M. Tornikoski (67) Y. Yatsu (85) A. Zook (90) ((1) IFAE Edifici Cn. Campus UAB E-08193 Bellaterra Spain (2) Universit\`a di Udine INFN Trieste I-33100 Udine Italy (3) INAF National Institute for Astrophysics I-00136 Rome (4) Universit\`a di Siena INFN Pisa I-53100 Siena (5) Croatian MAGIC Consortium Rudjer Boskovic Institute University of Rijeka University of Split HR-10000 Zagreb Croatia (6) Max-Planck-Institut f\"ur Physik D-80805 M\"unchen Germany (7) Universidad Complutense E-28040 Madrid (8) Inst. de Astrof\'isica de Canarias E-38200 La Laguna Tenerife (9) University of Lodz PL-90236 Lodz Poland (10) Deutsches Elektronen-Synchrotron (DESY) D-15738 Zeuthen (11) ETH Zurich CH-8093 Zurich Switzerland (12) Universit\"at W\"urzburg D-97074 W\"urzburg (13) Centro de Investigaciones Energ\'eticas Medioambientales y Tecnol\'ogicas (14) Technische Universit\"at Dortmund D-44221 Dortmund (15) Inst. de Astrof\'isica de Andaluc\'ia (CSIC) E-18080 Granada (16) Universit\`a di Padova INFN I-35131 Padova (17) Universit\`a dell'Insubria Como I-22100 Como (18) Unitat de F\'isica de les Radiacions Departament de F\'isica CERES-IEEC Universitat Aut\`onoma de Barcelona (19) Institut de Ci\`encies de l'Espai (IEEC-CSIC) (20) Finnish MAGIC Consortium Tuorla Observatory University of Turku Department of Physics University of Oulu Finland (21) Japanese MAGIC Consortium Division of Physics Astronomy Kyoto University Japan (22) Inst. for Nucl. 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Energy BG-1784 Sofia Bulgaria (23) Universitat de Barcelona (ICC/IEEC) E-08028 Barcelona (24) Universit\`a di Pisa I-56126 Pisa (25) now at Ecole polytechnique f\'ed\'erale de Lausanne (EPFL) Lausanne (26) now at Department of Physics \& Astronomy UC Riverside CA 92521 USA (27) now at Finnish Centre for Astronomy with ESO (FINCA) Turku (28) also at INAF-Trieste (29) also at Instituto de Fisica Teorica UAM/CSIC E-28049 Madrid (30) now at Stockholm University Fysikum Oskar Klein Centre AlbaNova SE-106 91 Stockholm Sweden (31) now at GRAPPA Institute University of Amsterdam 1098XH Amsterdam Netherlands (32) now at Stockholm University Department of Astronomy (33) Physics Department McGill University Montreal QC H3A 2T8 Canada (34) DESY Platanenallee 6 15738 Zeuthen (35) Department of Physics Washington University St. Louis MO 63130 (36) Fred Lawrence Whipple Observatory Harvard-Smithsonian Center for Astrophysics Amado AZ 85645 (37) School of Physics University College Dublin Belfield Dublin 4 Ireland (38) Institute of Physics University of Potsdam 14476 Potsdam-Golm (39) Astronomy Department Adler Planetarium Astronomy Museum Chicago IL 60605 (40) Department of Physics Purdue University West Lafayette IN 47907 (41) School of Physics University of Minnesota Minneapolis MN 55455 (42) Department of Physics Iowa State University Ames IA 50011 (43) Department of Astronomy Astrophysics 525 Davey Lab Pennsylvania State University University Park PA 16802 (44) Santa Cruz Institute for Particle Physics University of California Santa Cruz CA 95064 (45) Department of Physics University of Iowa Van Allen Hall Iowa City IA 52242 (46) Department of Physics the Bartol Research Institute University of Delaware Newark DE 19716 (47) Physics Department Columbia University New York NY 10027 (48) Department of Physics DePauw University Greencastle IN 46135-0037 (49) Department of Physics University of Utah Salt Lake City UT 84112 (50) School of Physics National University of Ireland Galway University Road Galway (51) Enrico Fermi Institute University of Chicago IL 60637 (52) School of Physics Center for Relativistic Astrophysics Georgia Institute of Technology 837 State Street NW Atlanta GA 30332-0430 (53) Department of Life Physical Sciences Galway-Mayo Institute of Technology Dublin Road (54) Department of Physics Barnard College (55) Department of Physics Los Angeles CA 90095 (56) Instituto de Astronomia y Fisica del Espacio Casilla de Correo 67 - Sucursal 28 (C1428ZAA) Ciudad Autonoma de Buenos Aires Argentina (57) Department of Applied Physics Instrumentation Cork Institute of Technology Bishopstown Cork (58) Argonne National Laboratory 9700 S. 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