36122
2012
2012
eng
18
2
746
article
IOP Publ. Ltd.
Bristol
HESS Collaboration, MAGIC Collaboration, VERITAS Collaboration
1
--
--
--
The 2010 very high energy gamma-ray flare and 10 years ofmulti-wavelength oservations of M 87
The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3-6) x 10(9) M-circle dot) provides a unique opportunity to investigate the origin of very high energy (VHE; E > 100 GeV) gamma-ray emission generated in relativistic outflows and the surroundings of supermassive black holes. M 87 has been established as a VHE gamma-ray emitter since 2006. The VHE gamma-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz Very Long Baseline Array, VLBA). The excellent sampling of the VHE gamma-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of tau(rise)(d) = (1.69 +/- 0.30) days and tau(decay)(d) = (0.611 +/- 0.080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (similar to day), peak fluxes (Phi(>0.35 TeV) similar or equal to (1-3) x 10(-11) photons cm(-2) s(-1)), and VHE spectra. VLBA radio observations of 43 GHz of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken similar to 3 days after the peak of the VHE gamma-ray emission reveal an enhanced flux from the core (flux increased by factor similar to 2; variability timescale <2 days). The long-term (2001-2010) multi-wavelength (MWL) light curve of M 87, spanning from radio to VHE and including data from Hubble Space Telescope, Liverpool Telescope, Very Large Array, and European VLBI Network, is used to further investigate the origin of the VHE gamma-ray emission. No unique, common MWL signature of the three VHE flares has been identified. In the outer kiloparsec jet region, in particular in HST-1, no enhanced MWL activity was detected in 2008 and 2010, disfavoring it as the origin of the VHE flares during these years. Shortly after two of the three flares (2008 and 2010), the X-ray core was observed to be at a higher flux level than its characteristic range (determined from more than 60 monitoring observations: 2002-2009). In 2005, the strong flux dominance of HST-1 could have suppressed the detection of such a feature. Published models for VHE gamma-ray emission from M 87 are reviewed in the light of the new data.
The astrophysical journal : an international review of spectroscopy and astronomical physics
10.1088/0004-637X/746/2/151
0004-637X
wos:2011-2013
151
WOS:000300406300037
Abramowski, A (reprint author), Univ Hamburg, Inst Expt Phys, Luruper Chaussee 149, D-22761 Hamburg, Germany., martin.raue@desy.de; stawarz@astro.isas.jaxa.jp; colin@mppmu.mpg.de; mazin@ifae.es; beilicke@physics.wustl.edu; cmhui@physics.utah.edu
Namibian authorities; German Ministry for Education and Research (BMBF);
Max Planck Society; French Ministry for Research; CNRS-IN2P3; CNRS; U.K.
Science and Technology Facilities Council (STFC); IPNP of the Charles
University; Polish Ministry of Science and Higher Education; South
African Department of Science and Technology; National Research
Foundation; University of Namibia; German BMBF; German MPG; Italian
INFN; Swiss National Fund SNF; Spanish MICINN; Bulgarian NSF
[CSD2007-00042, CSD2009-00064, DO02-353]; Academy of Finland [127740];
YIP of the Helmholtz Gemeinschaft; DFG Cluster of Excellence "Origin and
Structure of the Universe,"; 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; Istituto Nazionale di
Astrofisica in Italy; Centre National d'Etudes Spatiales in France; NASA
[GO0-11120X]; Associated Universities, Inc.; European Community [227290]
Attila Abramowski
F. Acero
Felix A. Aharonian
A. G. Akhperjanian
Gisela Anton
Arnim Balzer
Anna Barnacka
U. Barres de Almeida
Yvonne Becherini
J. Becker
B. Behera
K. Bernlöhr
E. Birsin
Jonathan Biteau
A. Bochow
Catherine Boisson
J. Bolmont
Pol Bordas
J. Brucker
Francois Brun
Pierre Brun
Tomasz Bulik
I. Buesching
Svenja Carrigan
Sabrina Casanova
M. Cerruti
Paula M. Chadwick
A. Charbonnier
Ryan C. G. Chaves
A. Cheesebrough
A. C. Clapson
G. Coignet
Gabriele Cologna
Jan Conrad
M. Dalton
M. K. Daniel
I. D. Davids
B. Degrange
C. Deil
H. J. Dickinson
A. Djannati-Ataï
W. Domainko
L. O'C. Drury
G. Dubus
K. Dutson
J. Dyks
M. Dyrda
Kathrin Egberts
P. Eger
P. Espigat
L. Fallon
C. Farnier
S. Fegan
F. Feinstein
M. V. Fernandes
A. Fiasson
G. Fontaine
A. Foerster
M. Fuessling
Y. A. Gallant
H. Gast
L. Gerard
D. Gerbig
B. Giebels
J. F. Glicenstein
B. Glueck
P. Goret
D. Goering
S. Haeffner
J. D. Hague
D. Hampf
M. Hauser
S. Heinz
G. Heinzelmann
G. Henri
G. Hermann
James Anthony Hinton
A. Hoffmann
W. Hofmann
P. Hofverberg
M. Holler
D. Horns
A. Jacholkowska
O. C. de Jager
C. Jahn
M. Jamrozy
I. Jung
M. A. Kastendieck
K. Katarzynski
U. Katz
S. Kaufmann
D. Keogh
D. Khangulyan
B. Khelifi
D. Klochkov
W. Kluzniak
T. Kneiske
Nu. Komin
K. Kosack
R. Kossakowski
H. Laffon
G. Lamanna
D. Lennarz
T. Lohse
A. Lopatin
C. -C. Lu
V. Marandon
A. Marcowith
J. Masbou
D. Maurin
N. Maxted
M. Mayer
T. J. L. McComb
M. C. Medina
J. Mehault
R. Moderski
E. Moulin
C. L. Naumann
M. Naumann-Godo
M. de Naurois
D. Nedbal
D. Nekrassov
N. Nguyen
B. Nicholas
J. Niemiec
S. J. Nolan
S. Ohm
E. de Ona Wilhelmi
B. Opitz
M. Ostrowski
I. Oya
M. Panter
M. Paz Arribas
G. Pedaletti
G. Pelletier
P. -O. Petrucci
S. Pita
G. Puehlhofer
M. Punch
A. Quirrenbach
M. Raue
S. M. Rayner
A. Reimer
O. Reimer
M. Renaud
R. de los Reyes
F. Rieger
J. Ripken
L. Rob
S. Rosier-Lees
G. Rowell
B. Rudak
C. B. Rulten
J. Ruppel
V. Sahakian
David M. Sanchez
A. Santangelo
R. Schlickeiser
F. M. Schoeck
A. Schulz
U. Schwanke
S. Schwarzburg
S. Schwemmer
F. Sheidaei
J. L. Skilton
H. Sol
G. Spengler
L. Stawarz
R. Steenkamp
Christian Stegmann
F. Stinzing
K. Stycz
Iurii Sushch
A. Szostek
J. -P. Tavernet
R. Terrier
M. Tluczykont
K. Valerius
C. van Eldik
G. Vasileiadis
C. Venter
J. P. Vialle
A. Viana
P. Vincent
H. J. Voelk
F. Volpe
S. Vorobiov
M. Vorster
S. J. Wagner
M. Ward
R. White
A. Wierzcholska
M. Zacharias
A. Zajczyk
A. A. Zdziarski
Alraune Zech
H. -S. Zechlin
J. Aleksic
L. A. Antonelli
P. Antoranz
Michael Backes
J. A. Barrio
D. Bastieri
J. Becerra Gonzalez
W. Bednarek
A. Berdyugin
K. Berger
E. Bernardini
A. Biland
O. Blanch Bigas
R. K. Bock
A. Boller
G. Bonnoli
D. Borla Tridon
I. Braun
T. Bretz
A. Canellas
E. Carmona
A. Carosi
P. Colin
E. Colombo
J. L. Contreras
J. Cortina
L. Cossio
S. Covino
F. Dazzi
A. De Angelis
E. De Cea del Pozo
B. De Lotto
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
C. Fruck
R. J. Garcia Lopez
M. Garczarczyk
D. Garrido
G. Giavitto
N. Godinovic
D. Hadasch
D. Haefner
A. Herrero
D. Hildebrand
D. Hoehne-Moench
J. Hose
D. Hrupec
B. Huber
T. Jogler
S. Klepser
T. Kraehenbuehl
J. Krause
A. La Barbera
D. Lelas
E. Leonardo
E. Lindfors
S. Lombardi
M. Lopez
E. Lorenz
M. 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
P. Munar
D. Nieto
K. Nilsson
R. Orito
I. Oya
D. Paneque
R. Paoletti
S. Pardo
J. M. Paredes
S. Partini
M. Pasanen
F. Pauss
M. A. Perez-Torres
M. Persic
L. Peruzzo
M. Pilia
J. Pochon
F. Prada
P. G. Prada Moroni
E. Prandini
I. Puljak
I. Reichardt
R. Reinthal
W. Rhode
M. Ribo
J. Rico
S. Ruegamer
A. Saggion
K. Saito
T. Y. Saito
M. Salvati
K. Satalecka
V. Scalzotto
V. Scapin
C. Schultz
T. Schweizer
M. Shayduk
S. N. Shore
A. Sillanpaa
J. Sitarek
D. Sobczynska
F. Spanier
S. Spiro
A. Stamerra
B. Steinke
J. Storz
N. Strah
T. Suric
L. Takalo
H. Takami
F. Tavecchio
P. Temnikov
T. Terzic
D. Tescaro
M. Teshima
M. Thom
O. Tibolla
D. F. Torres
A. Treves
H. Vankov
P. Vogler
R. M. Wagner
Q. Weitzel
V. Zabalza
F. Zandanel
R. Zanin
T. Arlen
T. Aune
M. Beilicke
W. Benbow
A. Bouvier
S. M. Bradbury
J. H. Buckley
V. Bugaev
K. Byrum
A. Cannon
A. Cesarini
L. Ciupik
M. P. Connolly
W. Cui
R. Dickherber
C. Duke
M. Errando
A. Falcone
J. P. Finley
G. Finnegan
L. Fortson
A. Furniss
N. Galante
D. Gall
S. Godambe
S. Griffin
J. Grube
G. Gyuk
D. Hanna
J. Holder
H. Huan
C. M. Hui
P. Kaaret
N. Karlsson
M. Kertzman
Y. Khassen
D. Kieda
H. Krawczynski
F. Krennrich
M. J. Lang
S. LeBohec
G. Maier
S. McArthur
A. McCann
P. Moriarty
R. Mukherjee
P. D. Nunez
R. A. Ong
M. Orr
A. N. Otte
N. Park
J. S. Perkins
A. Pichel
Martin Pohl
H. Prokoph
K. Ragan
L. C. Reyes
P. T. Reynolds
E. Roache
H. J. Rose
J. Ruppel
M. Schroedter
G. H. Sembroski
G. D. Sentuerk
Igor O. Telezhinsky
G. Tesic
M. Theiling
S. Thibadeau
A. Varlotta
V. V. Vassiliev
M. Vivier
S. P. Wakely
T. C. Weekes
D. A. Williams
B. Zitzer
U. Barres de Almeida
M. Cara
C. Casadio
C. C. Cheung
W. McConville
F. Davies
A. Doi
G. Giovannini
M. Giroletti
K. Hada
P. Hardee
D. E. Harris
W. Junor
M. Kino
N. P. Lee
C. Ly
J. Madrid
F. Massaro
C. G. Mundell
H. Nagai
E. S. Perlman
I. A. Steele
R. C. Walker
D. L. Wood
eng
uncontrolled
galaxies: active
eng
uncontrolled
galaxies: individual (M 87)
eng
uncontrolled
galaxies: jets
eng
uncontrolled
galaxies: nuclei
eng
uncontrolled
gamma rays: galaxies
eng
uncontrolled
radiation mechanisms: non-thermal
Institut für Physik und Astronomie
Referiert
34961
2013
2013
eng
7
6
554
article
EDP Sciences
Les Ulis
HESS Collaboration
1
--
--
--
HESS discovery of VHE gamma-rays from the quasar PKS 1510-089
The quasar PKS 1510-089 (z = 0.361) was observed with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes during high states in the optical and GeV bands, to search for very high energy (VHE, defined as E >= 0.1 TeV) emission. VHE gamma-rays were detected with a statistical significance of 9.2 standard deviations in 15.8 h of H. E. S. S. data taken during March and April 2009. A VHE integral flux of I(0.15 TeV < E < 1.0TeV) = (1.0 +/- 0.2(stat) +/- 0.2(sys)) x 10(-11) cm(-2) s(-1) is measured. The best-fit power law to the VHE data has a photon index of G = 5.4 +/- 0.7(stat) +/- 0.3(sys). The GeV and optical light curves show pronounced variability during the period of H.E.S.S. observations. However, there is insufficient evidence to claim statistically significant variability in the VHE data. Because of its relatively high redshift, the VHE flux from PKS 1510-089 should suffer considerable attenuation in the intergalactic space due to the extragalactic background light (EBL). Hence, the measured gamma-ray spectrum is used to derive upper limits on the opacity due to EBL, which are found to be comparable with the previously derived limits from relatively-nearby BL Lac objects. Unlike typical VHE-detected blazars where the broadband spectrum is dominated by nonthermal radiation at all wavelengths, the quasar PKS 1510-089 has a bright thermal component in the optical to UV frequency band. Among all VHE detected blazars, PKS 1510-089 has the most luminous broad line region. The detection of VHE emission from this quasar indicates a low level of gamma - gamma absorption on the internal optical to UV photon field.
Astronomy and astrophysics : an international weekly journal
10.1051/0004-6361/201321135
0004-6361
wos:2011-2013
A107
WOS:000320444200106
Behera, B (reprint author), DESY, Platanenallee 6, D-15738 Zeuthen, Germany., Bagmeet.Behera@desy.de
Namibian authorities; University of Namibia; German Ministry for
Education and Research (BMBF); Max Planck Society; German Research
Foundation (DFG); French Ministry for Research; CNRS [IN2P3];
Astroparticle Interdisciplinary Programme of the CNRS; UK Science and
Technology Facilities Council (STFC); IPNP of the Charles University;
Czech Science Foundation; Polish Ministry of Science and Higher
Education; South African Department of Science and Technology; National
Research Foundation; International Max Planck Research School (IMPRS)
for Astronomy & Cosmic Physics at the University of Heidelberg
Attila Abramowski
F. Acero
Felix A. Aharonian
A. G. Akhperjanian
Gisela Anton
Shangkari Balenderan
Arnim Balzer
Anna Barnacka
Yvonne Becherini
J. Becker Tjus
B. Behera
K. Bernlöhr
E. Birsin
Jonathan Biteau
A. Bochow
Catherine Boisson
J. Bolmont
Pol Bordas
J. Brucker
Francois Brun
Pierre Brun
Tomasz Bulik
Svenja Carrigan
Sabrina Casanova
M. Cerruti
Paula M. Chadwick
Ryan C. G. Chaves
A. Cheesebrough
Sergio Colafrancesco
Gabriele Cologna
Jan Conrad
C. Couturier
M. Dalton
M. K. Daniel
I. D. Davids
B. Degrange
C. Deil
P. deWilt
H. J. Dickinson
A. Djannati-Ataï
W. Domainko
L. O'C. Drury
G. Dubus
K. Dutson
J. Dyks
M. Dyrda
Kathrin Egberts
P. Eger
P. Espigat
L. Fallon
C. Farnier
S. Fegan
F. Feinstein
M. V. Fernandes
D. Fernandez
A. Fiasson
G. Fontaine
A. Foester
M. Fuessling
M. Gajdus
Y. A. Gallant
T. Garrigoux
H. Gast
B. Giebels
J. F. Glicenstein
B. Glueck
D. Goeing
M. -H. Grondin
M. Grudzinska
S. Haeffner
J. D. Hague
J. Hahn
D. Hampf
J. Harris
M. Hauser
S. Heinz
G. Heinzelmann
G. Henri
G. Hermann
A. Hillert
James Anthony Hinton
W. Hofmann
P. Hofverberg
Markus Holler
D. Horns
A. Jacholkowska
C. Jahn
M. Jamrozy
I. Jung
M. A. Kastendieck
K. Katarzynski
U. Katz
S. Kaufmann
B. Khelifi
S. Klepser
D. Klochkov
W. Kluzniak
T. Kneiske
Nu. Komin
K. Kosack
R. Kossakowski
F. Krayzel
P. P. Krueger
H. Laffon
G. Lamanna
J. Lefaucheur
M. Lemoine-Goumard
J. -P. Lenain
D. Lennarz
T. Lohse
A. Lopatin
C. -C. Lu
V. Marandon
A. Marcowith
J. Masbou
G. Maurin
N. Maxted
M. Mayer
T. J. L. McComb
M. C. Medina
J. Mehault
U. Menzler
R. Moderski
M. Mohamed
E. Moulin
C. L. Naumann
M. Naumann-Godo
M. de Naurois
D. Nedbal
N. Nguyen
J. Niemiec
S. J. Nolan
S. Ohm
E. de Ona Wilhelmi
B. Opitz
M. Ostrowski
I. Oya
M. Panter
R. D. Parsons
M. Paz Arribas
N. W. Pekeur
G. Pelletier
J. Perez
P. -O. Petrucci
B. Peyaud
S. Pita
G. Puehlhofer
M. Punch
A. Quirrenbach
S. Raab
M. Raue
A. Reimer
O. Reimer
M. Renaud
R. de los Reyes
F. Rieger
J. Ripken
L. Rob
S. Rosier-Lees
G. Rowell
B. Rudak
C. B. Rulten
V. Sahakian
David M. Sanchez
A. Santangelo
R. Schlickeiser
A. Schulz
U. Schwanke
S. Schwarzburg
S. Schwemmer
F. Sheidaei
J. L. Skilton
H. Sol
G. Spengler
L. Stawarz
R. Steenkamp
Christian Stegmann
F. Stinzing
K. Stycz
Iurii Sushch
A. Szostek
J. -P. Tavernet
R. Terrier
M. Tluczykont
C. Trichard
K. Valerius
C. van Eldik
G. Vasileiadis
C. Venter
A. Viana
P. Vincent
H. J. Voelk
F. Volpe
S. Vorobiov
M. Vorster
S. J. Wagner
M. Ward
R. White
A. Wierzcholska
D. Wouters
M. Zacharias
A. Zajczyk
A. A. Zdziarski
Alraune Zech
H. S. Zechlin
eng
uncontrolled
gamma rays: galaxies
eng
uncontrolled
quasars: individual: PKS 1510-089
eng
uncontrolled
infrared: diffuse background
Institut für Physik und Astronomie
Referiert
35105
2013
2013
eng
14
4
552
article
EDP SCIENCES S A
LES ULIS CEDEX A
HESS Collaboration
1
--
--
--
Discovery of TeV gamma-ray emission from PKS 0447-439 and derivation of
an upper limit on its redshift
Very high-energy gamma-ray emission from PKS 0447-439 was detected with the H. E. S. S. Cherenkov telescope array in December 2009. This blazar is one of the brightest extragalactic objects in the Fermi bright source list and has a hard spectrum in the MeV to GeV range. In the TeV range, a photon index of 3.89 +/- 0.37 (stat) +/- 0.22 (sys) and a flux normalisation at 1 TeV, phi(1) (TeV) = (3.5 +/- 1.1(stat) +/- 0.9(sys)) x 10(-13) cm(-2) s(-1) TeV-1 were found. The detection with H. E. S. S. triggered observations in the X-ray band with the Swift and RXTE telescopes. Simultaneous UV and optical data from Swift UVOT and data from the optical telescopes ATOM and ROTSE are also available. The spectrum and light curve measured with H. E. S. S. are presented and compared to the multi-wavelength data at lower energies. A rapid flare is seen in the Swift XRT and RXTE data, together with a flux variation in the UV band, at a time scale of the order of one day. A firm upper limit of z < 0.59 on the redshift of PKS 0447-439 is derived from the combined Fermi-LAT and H. E. S. S. data, given the assumptions that there is no upturn in the intrinsic spectrum above the Fermi-LAT energy range and that absorption on the extragalactic background light (EBL) is not weaker than the lower limit provided by current models. The spectral energy distribution is well described by a simple one-zone synchrotron self-Compton scenario, if the redshift of the source is less than z less than or similar to 0.4.
ASTRONOMY & ASTROPHYSICS
10.1051/0004-6361/201321108
0004-6361
wos:2011-2013
A118
WOS:000317912000117
Zech, A (reprint author), Univ Paris Diderot, CNRS, Observ Paris, LUTH, 5 Pl Jules Janssen, F-92190 Meudon, France.
, Bagmeet.Behera@desy.de; Andreas.Zech@obspm.fr
Attila Abramowski
F. Acero
A. G. Akhperjanian
Gisela Anton
Shangkari Balenderan
Arnim Balzer
Anna Barnacka
Yvonne Becherini
J. Becker Tjus
B. Behera
K. Bernlöhr
E. Birsin
Jonathan Biteau
A. Bochow
Catherine Boisson
J. Bolmont
Pol Bordas
J. Brucker
Francois Brun
Pierre Brun
Tomasz Bulik
Svenja Carrigan
Sabrina Casanova
M. Cerruti
Paula M. Chadwick
Ryan C. G. Chaves
A. Cheesebrough
Sergio Colafrancesco
Gabriele Cologna
Jan Conrad
C. Couturier
M. Dalton
M. K. Daniel
I. D. Davids
B. Degrange
C. Deil
P. deWilt
H. J. Dickinson
A. Djannati-Ataï
W. Domainko
L. O&rsquo Drury
C.
G. Dubus
K. Dutson
J. Dyks
M. Dyrda
Kathrin Egberts
P. Eger
P. Espigat
L. Fallon
C. Farnier
S. Fegan
F. Feinstein
M. V. Fernandes
D. Fernandez
A. Fiasson
G. Fontaine
A. Foerster
Matthias Fussling
M. Gajdus
Y. A. Gallant
T. Garrigoux
H. Gast
B. Giebels
J. F. Glicenstein
B. Glueck
D. Goering
M. -H. Grondin
M. Grudzinska
S. Haeffner
J. D. Hague
J. Hahn
D. Hampf
J. Harris
S. Heinz
G. Heinzelmann
G. Henri
G. Hermann
A. Hillert
James Anthony Hinton
W. Hofmann
P. Hofverberg
M. Holler
D. Horns
A. Jacholkowska
C. Jahn
M. Jamrozy
I. Jung
M. A. Kastendieck
K. Katarzynski
U. Katz
S. Kaufmann
B. Khelifi
S. Klepser
D. Klochkov
W. Kluzniak
T. Kneiske
D. Kolitzus
Nu Komin
K. Kosack
R. Kossakowski
F. Krayzel
P. P. Krueger
H. Laffon
G. Lamanna
J. Lefaucheur
M. Lemoine-Goumard
J. -P. Lenain
D. Lennarz
T. Lohse
A. Lopatin
C. -C. Lu
V. Marandon
A. Marcowith
J. Masbou
G. Maurin
N. Maxted
M. Mayer
T. J. L. McComb
M. C. Medina
J. Mehault
U. Menzler
R. Moderski
M. Mohamed
E. Moulin
C. L. Naumann
M. Naumann-Godo
M. de Naurois
D. Nedbal
N. Nguyen
J. Niemiec
S. J. Nolan
S. Ohm
E. de Ona Wilhelmi
B. Opitz
M. Ostrowski
I. Oya
M. Panter
R. D. Parsons
M. Paz Arribas
N. W. Pekeur
G. Pelletier
J. Perez
P. -O. Petrucci
B. Peyaud
S. Pita
G. Puehlhofer
M. Punch
A. Quirrenbach
S. Raab
M. Raue
A. Reimer
O. Reimer
M. Renaud
R. de los Reyes
F. Rieger
J. Ripken
L. Rob
S. Rosier-Lees
G. Rowell
B. Rudak
C. B. Rulten
V. Sahakian
David M. Sanchez
A. Santangelo
R. Schlickeiser
A. Schulz
U. Schwanke
S. Schwarzburg
S. Schwemmer
F. Sheidaei
J. L. Skilton
H. Sol
G. Spengler
L. Stawarz
R. Steenkamp
Christian Stegmann
F. Stinzing
K. Stycz
Iurii Sushch
A. Szostek
J. -P. Tavernet
R. Terrier
M. Tluczykont
C. Trichard
K. Valerius
C. van Eldik
G. Vasileiadis
C. Venter
A. Viana
P. Vincent
H. J. Voelk
F. Volpe
S. Vorobiov
M. Vorster
S. J. Wagner
M. Ward
R. White
A. Wierzcholska
D. Wouters
M. Zacharias
A. Zajczyk
A. A. Zdziarski
Alraune Zech
H. -S. Zechlin
D. Pelat
eng
uncontrolled
galaxies: active
eng
uncontrolled
BL Lacertae objects: individual: PKS 0447-439
eng
uncontrolled
radiation mechanisms: non-thermal
eng
uncontrolled
gamma rays: galaxies
37289
2014
2014
eng
11
2
797
article
IOP Publ. Ltd.
Bristol
Veritas Collaboration
1
--
--
--
Investigating broadband variability of the TeV blazar 1ES 1959+650
We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift Ultraviolet and Optical Telescope, X-ray observations by the Swift X-ray Telescope, high-energy gamma-ray observations with the Fermi Large Area Telescope, and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 2012 April 17 and 2012 June 1 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe the observations. As applied to an elevated VHE state of 66% of the Crab Nebula flux, observed on a single night during the observation period, the reflected emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV.
The astrophysical journal : an international review of spectroscopy and astronomical physics
10.1088/0004-637X/797/2/89
0004-637X
1538-4357
wos:2014
89
WOS:000346291600017
Aliu, E (reprint author), Columbia Univ, Barnard Coll, Dept Phys & Astron, New York, NY 10027 USA., amy.furniss@gmail.com; Markus.Bottcher@nwu.ac.za
U.S. Department of Energy Office of Science; U.S. National Science
Foundation; Smithsonian Institution; NSERC in Canada; Science Foundation
Ireland [SFI 10/RFP/AST2748]; STFC in the U.K
E. Aliu
S. Archambault
T. Arlen
T. Aune
Anna Barnacka
M. Beilicke
W. Benbow
K. Berger
R. Bird
A. Bouvier
J. H. Buckley
V. Bugaev
M. Cerruti
X. Chen
L. Ciupik
E. Collins-Hughes
M. P. Connolly
W. Cui
J. Dumm
J. D. Eisch
A. Falcone
S. Federici
Q. Feng
J. P. Finley
H. Fleischhack
P. Fortin
L. Fortson
A. Furniss
N. Galante
G. H. Gillanders
S. Griffin
S. T. Griffiths
J. Grube
G. Gyuk
N. Hakansson
D. Hanna
J. Holder
G. Hughes
Z. Hughes
T. B. Humensky
C. A. Johnson
P. Kaaret
P. Kar
M. Kertzman
Y. Khassen
D. Kieda
H. Krawczynski
F. Krennrich
M. J. Lang
A. S. Madhavan
P. Majumdar
S. McArthur
A. McCann
K. Meagher
J. Millis
P. Moriarty
R. Mukherjee
T. Nelson
D. Nieto
R. A. Ong
A. N. Otte
N. Park
J. S. Perkins
M. Pohl
A. Popkow
H. Prokoph
J. Quinn
K. Ragan
J. Rajotte
L. C. Reyes
P. T. Reynolds
G. T. Richards
E. Roache
A. Sadun
M. Santander
G. H. Sembroski
K. Shahinyan
F. Sheidaei
A. W. Smith
D. Staszak
Igor O. Telezhinsky
M. Theiling
J. Tyler
A. Varlotta
V. V. Vassiliev
S. Vincent
S. P. Wakely
T. C. Weekes
A. Weinstein
R. Welsing
Alina Wilhelm
D. A. Williams
B. Zitzer
Markus Boettcher
M. Fumagalli
eng
uncontrolled
BL Lacertae objects: individual (1ES 1959+650)
eng
uncontrolled
gamma rays: galaxies
Institut für Physik und Astronomie
Referiert
44871
2016
2016
eng
12
594
article
EDP Sciences
Les Ulis
Veritas Collaboration
1
--
--
--
Very high energy outburst of Markarian 501 in May 2009
The very high energy (VHE; E > 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54 938-54 956), 2009, as part of an extensive multiwavelength campaign from radio to VHE. Strong VHE yray activity was detected on May 1st with Whipple and VERITAS, when the flux (E > 400 GeV) increased to 10 times the preflare baseline flux (3.9 x 10(-11) ph cm(-2) s(-1)), reaching five times the flux of the Crab Nebula. This coincided with a decrease in the optical polarization and a rotation of the polarization angle by 15. This VHE flare showed a fast flux variation with an increase of a factor similar to 4 in 25 min, and a falling time of similar to 50 min. We present the observations of the quiescent state previous to the flare and of the high state after the flare, focusing on the flux and spectral variability from Whipple, VERITAS, Fermi-LAT, RXTE, and Swift combined with optical and radio data.
Physical chemistry, chemical physics : a journal of European Chemical Societies
10.1051/0004-6361/201628744
1432-0746
wos2016:2019
A76
WOS:000385832200085
Pichel, A (reprint author), Inst Astron & Fis Espacio, Casilla Correo 67,Sucursal 28,C1428ZAA, Buenos Aires, DF, Argentina., anapichel@iafe.uba.ar
US Department of Energy Office of Science; US National Science Foundation; Smithsonian Institution; NSERC in Canada; South African Research Chairs Initiative (SARChI) by National Research Foundation; Department of Science and Technology of South Africa
importub
2020-03-22T13:48:01+00:00
filename=package.tar
9eac71db8d99b6f78ad5d64f40931fa9
E. Aliu
S. Archambault
A. Archer
T. Arlen
T. Aune
Anna Barnacka
B. Behera
M. Beilicke
W. Benbow
K. Berger
R. Bird
Markus Böttcher
A. Bouvier
M. Buchovecky
J. H. Buckley
V. Bugaev
J. V. Cardenzana
M. Cerruti
A. Cesarini
Xuhui Chen
L. Ciupik
E. Collins-Hughes
M. P. Connolly
W. Cui
J. Dumm
J. D. Eisch
A. Falcone
Simone Federici
Q. Feng
J. P. Finley
H. Fleischhack
P. Fortin
L. Fortson
A. Furniss
N. Galante
D. Gall
G. H. Gillanders
S. Griffin
S. T. Griffiths
J. Grube
G. Gyuk
M. Hütten
Nils Hakansson
J. Holder
G. Hughes
T. B. Humensky
C. A. Johnson
P. Kaaret
P. Kar
N. Kelley-Hoskins
M. Kertzman
Y. Khassen
D. Kieda
M. Krause
H. Krawczynski
F. Krennrich
M. J. Lang
A. S. Madhavan
G. Maier
S. McArthur
A. McCann
K. Meagher
J. Millis
P. Moriarty
R. Mukherjee
D. Nieto
R. A. Ong
M. Orr
A. N. Otte
D. Pandel
N. Park
V. Pelassa
J. S. Perkins
A. Pichel
Martin Pohl
A. Popkow
J. Quinn
K. Ragan
L. C. Reyes
P. T. Reynolds
E. Roache
J. Rousselle
A. C. Rovero
D. B. Saxon
G. H. Sembroski
K. Shahinyan
F. Sheidaei
C. Skole
A. W. Smith
D. Staszak
Igor O. Telezhinsky
M. Theiling
N. W. Todd
J. V. Tucci
J. Tyler
A. Varlotta
V. V. Vassiliev
S. Vincent
S. P. Wakely
O. M. Weiner
A. Weinstein
R. Welsing
Alina Wilhelm
D. A. Williams
B. Zitzer
M. G. Baring
J. Becerra Gonzalez
A. N. Cillis
D. Horan
D. Paneque
eng
uncontrolled
BL Lacertae objects: individual: Mrk 501
eng
uncontrolled
gamma rays: galaxies
Institut für Physik und Astronomie
Referiert
Import