We present very high energy (E > 100GeV) γ-ray observations of the γ-ray binary system LS I +61°303 obtained with the MAGIC stereo system between 2009 October and 2010 January. We detect a 6.3σ γ-ray signal above 400GeV in the combined data set. The integral flux above an energy of 300GeV is F(E > 300 GeV) = (1.4 ± 0.3stat ± 0.4syst) × 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°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°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. © 2012. The American Astronomical Society. All rights reserved.

J., A., E. A., A., L. A., A., P., A., M., A., M., B., et al. (2012). Detection of the γ-ray binary LSI +61°303 in a low-flux state at very high energy γ-rays with the magic telescopes in 2009. THE ASTROPHYSICAL JOURNAL, 746(1) [10.1088/0004-637X/746/1/80].

Detection of the γ-ray binary LSI +61°303 in a low-flux state at very high energy γ-rays with the magic telescopes in 2009

BONNOLI, GIACOMO;LEONARDO, ELVIRA;MEUCCI, MARIO;PAOLETTI, RICCARDO;PARTINI, SERENA;STAMERRA, ANTONIO;
2012-01-01

Abstract

We present very high energy (E > 100GeV) γ-ray observations of the γ-ray binary system LS I +61°303 obtained with the MAGIC stereo system between 2009 October and 2010 January. We detect a 6.3σ γ-ray signal above 400GeV in the combined data set. The integral flux above an energy of 300GeV is F(E > 300 GeV) = (1.4 ± 0.3stat ± 0.4syst) × 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°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°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. © 2012. The American Astronomical Society. All rights reserved.
J., A., E. A., A., L. A., A., P., A., M., A., M., B., et al. (2012). Detection of the γ-ray binary LSI +61°303 in a low-flux state at very high energy γ-rays with the magic telescopes in 2009. THE ASTROPHYSICAL JOURNAL, 746(1) [10.1088/0004-637X/746/1/80].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/25501
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