37044
2011
2011
eng
26
2
727
article
IOP Publ. Ltd.
Bristol
Fermi-LAT Collaboration, MAGIC Collaboration, VERITAS Collaboration
1
--
--
--
Insights into the high-energy gamma-Ray emission of markarian 501 fromextensive multifrequency observations in the fermi era
We report on the gamma-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) gamma-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 +/- 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 +/- 0.14, and the softest one is 2.51 +/- 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size less than or similar to 0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (similar or equal to 10(44) erg s(-1)) constitutes only a small fraction (similar to 10(-3)) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude.
The astrophysical journal : an international review of spectroscopy and astronomical physics
10.1088/0004-637X/727/2/129
0004-637X
wos:2011-2013
129
WOS:000286662000068
Paneque, D (reprint author), Stanford Univ, Dept Phys, WW Hansen Expt Phys Lab, Kavli Inst Particle Astrophys & Cosmol, Stanford, CA 94305 USA., dpaneque@mppmu.mpg.de; stawarz@astro.isas.jaxa.jp
K. A. Wallenberg Foundation; International Doctorate on Astroparticle
Physics (IDAPP) program; INFN Padova; Academy of Finland [212656,
210338]; National Radio Astronomy Observatory's Very Long Baseline Array
(VLBA) [BK150, BP143, MOJAVE]; Russian RFBR foundation [09-02-00092];
Georgian National Science Foundation [GNSF/ST07/4-180]; NASA
[NNX08AW31G]; NSF [AST-0808050]
A. A. Abdo
Margit Ackermann
M. Ajello
A. J. Allafort
L. Baldini
J. Ballet
G. Barbiellini
M. G. Baring
D. Bastieri
K. C. Bechtol
R. Bellazzini
B. Berenji
R. D. Blandford
E. D. Bloom
E. Bonamente
A. W. Borgland
A. Bouvier
T. J. Brandt
Johan Bregeon
A. Brez
M. Brigida
P. Bruel
R. Buehler
S. Buson
G. A. Caliandro
R. A. Cameron
A. Cannon
P. A. Caraveo
Svenja Carrigan
J. M. Casandjian
E. Cavazzuti
C. Cecchi
O. Celik
E. Charles
A. Chekhtman
C. C. Cheung
J. Chiang
S. Ciprini
R. Claus
J. Cohen-Tanugi
Jan Conrad
S. Cutini
C. D. Dermer
F. de Palma
E. do Couto e Silva
P. S. Drell
R. Dubois
D. Dumora
C. Favuzzi
S. J. Fegan
E. C. Ferrara
W. B. Focke
P. Fortin
M. Frailis
L. Fuhrmann
Y. Fukazawa
S. Funk
P. Fusco
F. Gargano
D. Gasparrini
N. Gehrels
S. Germani
N. Giglietto
F. Giordano
M. Giroletti
T. Glanzman
G. Godfrey
I. A. Grenier
L. Guillemot
S. Guiriec
M. Hayashida
E. Hays
D. Horan
R. E. Hughes
G. Johannesson
A. S. Johnson
W. N. Johnson
M. Kadler
T. Kamae
H. Katagiri
J. Kataoka
J. Knoedlseder
M. Kuss
J. Lande
L. Latronico
S. -H. Lee
M. Lemoine-Goumard
F. Longo
F. Loparco
B. Lott
M. N. Lovellette
P. Lubrano
G. M. Madejski
A. Makeev
W. Max-Moerbeck
Mario Nicola Mazziotta
J. E. McEnery
J. Mehault
P. F. Michelson
W. Mitthumsiri
T. Mizuno
A. A. Moiseev
C. Monte
M. E. Monzani
A. Morselli
I. V. Moskalenko
S. Murgia
M. Naumann-Godo
S. Nishino
P. L. Nolan
J. P. Norris
E. Nuss
T. Ohsugi
A. Okumura
N. Omodei
E. Orlando
J. F. Ormes
D. Paneque
J. H. Panetta
D. Parent
V. Pavlidou
T. J. Pearson
V. Pelassa
M. Pepe
M. Pesce-Rollins
F. Piron
T. A. Porter
S. Raino
R. Rando
M. Razzano
A. Readhead
A. Reimer
O. Reimer
J. L. Richards
J. Ripken
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J. D. Scargle
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P. D. Smith
G. Spandre
P. Spinelli
L. Stawarz
M. Stevenson
M. S. Strickman
K. V. Sokolovsky
D. J. Suson
H. Takahashi
T. Takahashi
T. Tanaka
J. B. Thayer
J. G. Thayer
D. J. Thompson
L. Tibaldo
F. Torres
G. Tosti
A. Tramacere
Y. Uchiyama
T. L. Usher
J. Vandenbroucke
V. Vasileiou
N. Vilchez
V. Vitale
A. P. Waite
P. Wang
A. E. Wehrle
B. L. Winer
K. S. Wood
Z. Yang
T. Ylinen
J. A. Zensus
M. Ziegler
J. Aleksic
L. A. Antonelli
P. Antoranz
Michael Backes
J. A. Barrio
J. Becerra Gonzalez
W. Bednarek
A. Berdyugin
K. Berger
E. Bernardini
A. Biland
O. Blanch Bigas
R. K. Bock
A. Boller
G. Bonnoli
Pol Bordas
D. Borla Tridon
Valentin Bosch-Ramon
D. Bose
I. Braun
T. Bretz
M. Camara
E. Carmona
A. Carosi
P. Colin
E. Colombo
J. L. Contreras
J. Cortina
S. Covino
F. Dazzi
A. de Angelis
E. De Cea del Pozo
B. De Lotto
M. De Maria
F. De Sabata
C. Delgado Mendez
A. Diago Ortega
M. Doert
A. Dominguez
Dijana Dominis Prester
D. Dorner
M. Doro
D. Elsaesser
D. Ferenc
M. V. Fonseca
L. Font
R. J. Garcia Lopen
M. Garczarczyk
M. Gaug
G. Giavitto
N. Godinovi
D. Hadasch
A. Herrero
D. Hildebrand
D. Hoehne-Moench
J. Hose
D. Hrupec
T. Jogler
S. Klepser
T. Kraehenbuehl
D. Kranich
J. Krause
A. La Barbera
E. Leonardo
E. Lindfors
S. Lombardi
M. Lopez
E. Lorenz
P. Majumdar
E. Makariev
G. Maneva
N. Mankuzhiyil
K. Mannheim
L. Maraschi
M. Mariotti
M. Martinez
D. Mazin
M. Meucci
J. M. Miranda
R. Mirzoyan
H. Miyamoto
J. Moldon
A. Moralejo
D. Nieto
K. Nilsson
R. Orito
I. Oya
R. Paoletti
J. M. Paredes
S. Partini
M. Pasanen
F. Pauss
R. G. Pegna
M. A. Perez-Torres
M. Persic
J. Peruzzo
J. Pochon
P. G. Prada Moroni
F. Prada
E. Prandini
N. Puchades
I. Puljak
T. Reichardt
R. Reinthal
W. Rhode
M. Ribo
J. Rico
M. Rissi
S. Ruegamer
A. Saggion
K. Saito
T. Y. Saito
M. Salvati
M. Sanchez-Conde
K. Satalecka
V. Scalzotto
V. Scapin
C. Schultz
T. Schweizer
M. Shayduk
S. N. Shore
A. Sierpowska-Bartosik
A. Sillanpaa
J. Sitarek
D. Sobczynska
F. Spanier
S. Spiro
A. Stamerra
B. Steinke
J. Storz
N. Strah
J. C. Struebig
T. Suric
L. O. Takalo
F. Tavecchio
P. Temnikov
T. Terzic
D. Tescaro
M. Teshima
H. Vankov
R. M. Wagner
Q. Weitzel
V. Zabalza
F. Zandanel
R. Zanin
V. A. Acciari
T. Arlen
T. Aune
W. Benbow
D. Boltuch
S. M. Bradbury
J. H. Buckley
V. Bugaev
A. Cannon
A. Cesarini
L. Ciupik
W. Cui
R. Dickherber
M. Errando
A. Falcone
J. P. Finley
G. Finnegan
L. Fortson
A. Furniss
N. Galante
D. Gall
G. H. Gillanders
S. Godambe
J. Grube
R. Guenette
G. Gyuk
D. Hanna
J. Holder
D. Huang
C. M. Hui
T. B. Humensky
P. Kaaret
N. Karlsson
M. Kertzman
D. Kieda
A. Konopelko
H. Krawczynski
F. Krennrich
M. J. Lang
G. Maier
S. McArthur
A. McCann
M. McCutcheon
P. Moriarty
R. Mukherjee
R. Ong
N. Otte
D. Pandel
J. S. Perkins
A. Pichel
M. Pohl
J. Quinn
K. Ragan
L. C. Reyes
P. T. Reynolds
E. Roache
H. J. Rose
A. C. Rovero
M. Schroedter
G. H. Sembroski
G. D. Senturk
D. Steele
S. P. Swordy
G. Tesic
M. Theiling
S. Thibadeau
A. Varlotta
S. Vincent
S. P. Wakely
J. E. Ward
T. C. Weekes
A. Weinstein
T. Weisgarber
D. A. Williams
M. Wood
B. Zitzer
M. Villata
C. M. Raiteri
H. D. Aller
M. F. Aller
A. A. Arkharov
D. A. Blinov
P. Calcidese
W. P. Chen
N. V. Efimova
G. Kimeridze
T. S. Konstantinova
E. N. Kopatskaya
E. Koptelova
O. M. Kurtanidze
S. O. Kurtanidze
A. Lahteenmaki
V. M. Larionov
E. G. Larionova
L. V. Larionova
R. Ligustri
D. A. Morozova
M. G. Nikolashvili
L. A. Sigua
I. S. Troitsky
E. Angelakis
M. Capalbi
A. Carraminana
L. Carrasco
P. Cassaro
E. de la Fuente
M. A. Gurwell
Y. Y. Kovalev
Yu. A. Kovalev
T. P. Krichbaum
H. A. Krimm
Paolo Leto
M. L. Lister
G. Maccaferri
J. W. Moody
Y. Mori
I. Nestoras
A. Orlati
C. Pagani
C. Pace
R. Pearson
M. Perri
B. G. Piner
A. B. Pushkarev
E. Ros
A. C. Sadun
T. Sakamoto
M. Tornikoski
Y. Yatsu
A. Zook
eng
uncontrolled
acceleration of particles
eng
uncontrolled
BL Lacertae objects: general
eng
uncontrolled
BL Lacertae objects: individual (Mrk 501)
eng
uncontrolled
galaxies: active
eng
uncontrolled
gamma rays: general
eng
uncontrolled
radiation mechanisms: non-thermal
Institut für Physik und Astronomie
Referiert
38849
2015
2015
eng
26
578
article
EDP Sciences
Les Ulis
MAGIC Collaboration, VERITAS Collaboration
1
--
--
--
Unprecedented study of the broadband emission of Mrk 421 during flaring activity in March 2010
Context. Because of its proximity, Mrk 421 is one of the best sources on which to study the nature of BL Lac objects. Its proximity allows us to characterize its broadband spectral energy distribution (SED).
Aims. The goal is to better understand the mechanisms responsible for the broadband emission and the temporal evolution of Mrk 421. These mechanisms may also apply to more distant blazars that cannot be studied with the same level of detail.
Methods. A flare occurring in March 2010 was observed for 13 consecutive days (from MJD 55 265 to MJD 55 277) with unprecedented wavelength coverage from radio to very high energy (VHE; E > 100 GeV) gamma-rays with MAGIC, VERITAS, Whipple, Fermi-LAT, MAXI, RXTE, Swift, GASP-WEBT, and several optical and radio telescopes. We modeled the day-scale SEDs with one-zone and two-zone synchrotron self-Compton (SSC) models, investigated the physical parameters, and evaluated whether the observed broadband SED variability can be associated with variations in the relativistic particle population.
Results. The activity of Mrk 421 initially was high and then slowly decreased during the 13-day period. The flux variability was remarkable at the X-ray and VHE bands, but it was minor or not significant at the other bands. The variability in optical polarization was also minor. These observations revealed an almost linear correlation between the X-ray flux at the 2-10 keV band and the VHE gamma-ray flux above 200 GeV, consistent with the gamma-rays being produced by inverse-Compton scattering in the Klein-Nishina regime in the framework of SSC models. The one-zone SSC model can describe the SED of each day for the 13 consecutive days reasonably well, which once more shows the success of this standard theoretical scenario to describe the SEDs of VHE BL Lacs such as Mrk 421. This flaring activity is also very well described by a two-zone SSC model, where one zone is responsible for the quiescent emission, while the other smaller zone, which is spatially separated from the first, contributes to the daily variable emission occurring at X-rays and VHE gamma-rays. The second blob is assumed to have a smaller volume and a narrow electron energy distribution with 3 x 10(4) < gamma < 6 x 10(5), where. is the Lorentz factor of the electrons. Such a two-zone scenario would naturally lead to the correlated variability at the X-ray and VHE bands without variability at the optical/UV band, as well as to shorter timescales for the variability at the X-ray and VHE bands with respect to the variability at the other bands.
Conclusions. Both the one-zone and the two-zone SSC models can describe the daily SEDs via the variation of only four or five model parameters, under the hypothesis that the variability is associated mostly with the underlying particle population. This shows that the particle acceleration and cooling mechanism that produces the radiating particles might be the main mechanism responsible for the broadband SED variations during the flaring episodes in blazars. The two-zone SSC model provides a better agreement with the observed SED at the narrow peaks of the low-and high-energy bumps during the highest activity, although the reported one-zone SSC model could be further improved by varying the parameters related to the emitting region itself (delta, B and R), in addition to the parameters related to the particle population.
Astronomy and astrophysics : an international weekly journal
10.1051/0004-6361/201424811
0004-6361
1432-0746
wos:2015
A22
WOS:000357502600034
Paneque, D (reprint author), Max Planck Inst Phys & Astrophys, D-80805 Munich, Germany., dpaneque@mpp.mpg.de; sysun@mpp.mpg.de; takami@post.kek.jp
German BMBF; German MPG; Italian INFN; Italian INAF; Swiss National Fund
SNF; ERDF under the Spanish MINECO; Japanese JSPS; Japanese MEXT; Centro
de Excelencia Severo Ochoa project of the Spanish Consolider-Ingenio
programme [SEV-2012-0234]; CPAN project of the Spanish
Consolider-Ingenio programme [CSD2007-00042]; MultiDark project of the
Spanish Consolider-Ingenio programme [CSD2009-00064]; Academy of Finland
[268740, 212656, 210338, 121148]; Croatian Science Foundation (HrZZ)
Project [09/176]; University of Rijeka [13.12.1.3.02]; DFG Collaborative
Research Centers [SFB823/C4, SFB876/C3]; Polish MNiSzW
[745/N-HESS-MAGIC/2010/0]; US Department of Energy Office of Science; US
National Science Foundation; Smithsonian Institution; NSERC in Canada;
Science Foundation Ireland [SFI 10/RFP/AST2748]; STFC in the UK; NASA
[NNX11AQ03G, NNX08AW31G, NNX11A043G]; Academia Sinica; NSF [AST-0808050,
AST-1109911]; Russian RFBR [12-02-00452]; St. Petersburg University
[6.0.163.2010, 6.38.71.2012]; Georgian National Science Foundation
[GNSF/ST07/4-180]; Shota Rustaveli National Science Foundation
[FR/577/6-320/13]
J. Aleksic
S. Ansoldi
L. A. Antonelli
P. Antoranz
A. Babic
P. Bangale
U. Barres de Almeida
J. A. Barrio
J. Becerra Gonzalez
W. Bednarek
E. Bernardini
B. Biasuzzi
A. Biland
O. Blanch Bigas
A. Boller
S. Bonnefoy
G. Bonnoli
F. Borracci
T. Bretz
E. Carmona
A. Carosi
P. Colin
E. Colombo
J. L. Contreras
J. Cortina
S. Covino
P. Da Vela
F. Dazzi
A. De Angelis
G. De Caneva
B. De Lotto
E. de Ona Wilhelmi
C. Delgado Mendez
Dijana Dominis Prester
D. Dorner
M. Doro
S. Einecke
D. Eisenacher
D. Elsaesser
M. V. Fonseca
L. Font
K. Frantzen
C. Fruck
D. Galindo
R. J. Garcia Lopez
M. Garczarczyk
D. Garrido Terrats
M. Gaug
N. Godinovic
A. Gonzalez Munoz
S. R. Gozzini
D. Hadasch
Y. Hanabata
M. Hayashida
J. Herrera
D. Hildebrand
J. Hose
D. Hrupec
G. Hughes
W. Idec
V. Kadenius
H. Kellermann
M. L. Knoetig
K. Kodani
Y. Konno
J. Krause
H. Kubo
J. Kushida
A. La Barbera
D. Lelas
N. Lewandowska
E. Lindfors
S. Lombardi
M. Lopez
R. Lopez-Coto
A. Lopez-Oramas
E. Lorenz
I. Lozano
M. Makariev
K. Mallot
G. Maneva
N. Mankuzhiyil
K. Mannheim
L. Maraschi
B. Marcote
M. Mariotti
M. Martinez
D. Mazin
U. Menzel
J. M. Miranda
R. Mirzoyan
A. Moralejo
P. Munar-Adrover
D. Nakajima
A. Niedzwiecki
K. Nilsson
K. Nishijima
K. Noda
R. Orito
A. Overkemping
S. Paiano
M. Palatiello
D. Paneque
R. Paoletti
J. M. Paredes
X. Paredes-Fortuny
M. Persic
P. G. Prada Moroni
E. Prandini
I. Puljak
R. Reinthal
W. Rhode
M. Ribo
J. Rico
J. Rodriguez Garcia
S. Rugamer
T. Saito
K. Saito
K. Satalecka
V. Scalzotto
V. Scapin
C. Schultz
T. Schweizer
S. Sun
S. N. Shore
A. Sillanpaa
J. Sitarek
I. Snidaric
D. Sobczynska
F. Spanier
V. Stamatescu
A. Stamerra
T. Steinbring
B. Steinke
J. Storz
M. Strzys
L. Takalo
H. Takami
F. Tavecchio
P. Temnikov
T. Terzic
D. Tescaro
M. Teshima
J. Thaele
O. Tibolla
D. F. Torres
T. Toyama
A. Treves
M. Uellenbeck
P. Vogler
R. Zanin
S. Archambault
A. Archer
M. Beilicke
W. Benbow
K. Berger
R. Bird
Jonathan Biteau
J. H. Buckley
V. Bugaev
M. Cerruti
Xiaoming Chen
L. Ciupik
E. Collins-Hughes
W. Cui
J. D. Eisch
A. Falcone
Q. Feng
J. P. Finley
P. Fortin
L. Fortson
A. Furniss
N. Galante
G. H. Gillanders
S. Griffin
G. Gyuk
Nils Hakansson
J. Holder
C. A. Johnson
P. Kaaret
P. Kar
M. Kertzman
D. Kieda
M. J. Lang
S. McArthur
A. McCann
K. Meagher
J. Millis
P. Moriarty
R. A. Ong
A. N. Otte
J. S. Perkins
A. Pichel
Manuela Pohl
A. Popkow
H. Prokoph
Elisa Pueschel
K. Ragan
L. C. Reyes
P. T. Reynolds
G. T. Richards
E. Roache
A. C. Rovero
G. H. Sembroski
K. Shahinyan
D. Staszak
Igor O. Telezhinsky
J. V. Tucci
J. Tyler
A. Varlotta
S. P. Wakely
R. Welsing
Alina Wilhelm
D. A. Williams
S. Buson
J. Finke
M. Villata
C. Raiteri
H. D. Aller
M. F. Aller
A. Cesarini
W. P. Chen
M. A. Gurwell
S. G. Jorstad
G. N. Kimeridze
E. Koptelova
O. M. Kurtanidze
S. O. Kurtanidze
A. Lahteenmaki
V. M. Larionov
E. G. Larionova
H. C. Lin
B. McBreen
J. W. Moody
D. A. Morozova
A. P. Marscher
W. Max-Moerbeck
M. G. Nikolashvili
M. Perri
A. C. S. Readhead
J. L. Richards
J. A. Ros
A. C. Sadun
T. Sakamoto
L. A. Sigua
P. S. Smith
M. Tornikoski
I. S. Troitsky
A. E. Wehrle
B. Jordan
eng
uncontrolled
radiation mechanisms: non-thermal
eng
uncontrolled
galaxies: active
eng
uncontrolled
BL Lacertae objects: individual: Mrk 421
eng
uncontrolled
gamma rays: galaxies
Institut für Physik und Astronomie
Referiert