RT Journal Article
T1 Detection of the gamma-ray binary LS I+61 degrees 303 in a low-flux state at very high energy gamma-rays with the magic telescopes in 2009
A1 Antoranz Canales, Pedro
A1 Barrio Uña, Juan Abel
A1 Contreras González, José Luis
A1 Fonseca González, Mª Victoria
A1 Miranda Pantoja, José Miguel
A1 Scapin, Valeria
AB We present very high energy (E > 100 GeV) gamma-ray observations of the gamma-ray binary system LS I +61 degrees 303 obtained with the MAGIC stereo system between 2009 October and 2010 January. We detect a 6.3 sigma gamma-ray signal above 400 GeV in the combined data set. The integral flux above an energy of 300 GeV is F(E > 300 GeV) = (1.4 +/- 0.3(stat) +/- 0.4(syst)) x 10(-12) cm(-2) s(-1), which corresponds to about 1.3% of the Crab Nebula flux in the same energy range. The orbit-averaged flux of LS I +61 degrees 303 in the orbital phase interval 0.6-0.7, where a maximum of the TeV flux is expected, is lower by almost an order of magnitude compared to our previous measurements between 2005 September and 2008 January. This provides evidence for a new low-flux state in LS I +61 degrees 303. We find that the change to the low-flux state cannot be solely explained by an increase of photon-photon absorption around the compact star.
PB IOP Publishing
SN 0004-637X
YR 2012
FD 2012-02-10
LK https://hdl.handle.net/20.500.14352/43819
UL https://hdl.handle.net/20.500.14352/43819
LA eng
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NO © The American Astronomical Society. We thank the Instituto de Astrofisica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the Marie Curie program, bythe CPAN CSD2007-00042 and MultiDark CSD2009-00064projects of the Spanish Consolider-Ingenio 2010 programme,by grant DO02-353 of the Bulgarian NSF, by grant 127740of the Academy of Finland, by the YIP of the HelmholtzGemeinschaft, by the DFG Cluster of Excellence “Origin andStructure of the Universe,” and by the Polish MNiSzW GrantN N203 390834
NO German BMBF
NO German MPG
NO Italian INFN
NO Swiss National Fund SNF
NO Spanish MICINN
NO Marie Curie
NO YIP of the Helmholtz Gemeinschaft
NO DFG Cluster of Excellence "Origin and Structure of the Universe"
NO CPAN
NO Bulgarian NSF
NO Academy of Finland
NO Polish MNiSzW
NO MultiDark
DS Docta Complutense
RD 30 abr 2024