dc.contributor.author | Abramowski, A. | |
dc.contributor.author | Böttcher, M. | |
dc.contributor.author | Davids, I.D. | |
dc.contributor.author | Ivascenko, A. | |
dc.contributor.author | Krüger, P.P. | |
dc.contributor.author | Pekeur, N.W. | |
dc.contributor.author | Seyffert, A.S. | |
dc.contributor.author | Spanier, F. | |
dc.contributor.author | Sushch, I. | |
dc.contributor.author | Van der Walt, D.J. | |
dc.contributor.author | Venter, C. | |
dc.contributor.author | H.E.S.S. Collaboration | |
dc.date.accessioned | 2016-08-30T10:52:14Z | |
dc.date.available | 2016-08-30T10:52:14Z | |
dc.date.issued | 2015 | |
dc.identifier.citation | Abramowski, A. et al. 2015. Discovery of variable VHE γ-ray emission from the binary system 1FGL J1018.6-5856. Astronomy & astrophysics, 577: Article no A131. [https://doi.org/10.1051/0004-6361/201525699] | en_US |
dc.identifier.issn | 0004-6361 | |
dc.identifier.issn | 1432-0746 (Online) | |
dc.identifier.uri | http://hdl.handle.net/10394/18448 | |
dc.identifier.uri | https://doi.org/10.1051/0004-6361/201525699 | |
dc.identifier.uri | http://www.aanda.org/articles/aa/full_html/2015/05/aa25699-15/aa25699-15.html | |
dc.description.abstract | Re-observations with the HESS telescope array of the very high-energy (VHE) source HESS J1018–589 A that is coincident with the Fermi-LAT γ-ray binary 1FGL J1018.6–5856 have resulted in a source detection significance of more than 9σ and the detection of variability (χ2/ν of 238.3/155) in the emitted γ-ray flux. This variability confirms the association of HESS J1018–589 A with the high-energy γ-ray binary detected by Fermi-LAT and also confirms the point-like source as a new VHE binary system. The spectrum of HESS J1018–589 A is best fit with a power-law function with photon index Γ = 2.20 ± 0.14stat ± 0.2sys. Emission is detected up to ~20 TeV. The mean differential flux level is (2.9 ± 0.4) × 10-13 TeV-1 cm-2 s-1 at 1 TeV, equivalent to ~1% of the flux from the Crab Nebula at the same energy. Variability is clearly detected in the night-by-night light curve. When folded on the orbital period of 16.58 days, the rebinned light curve peaks in phase with the observed X-ray and high-energy phaseograms. The fit of the HESS phaseogram to a constant flux provides evidence of periodicity at the level of Nσ> 3σ. The shape of the VHE phaseogram and measured spectrum suggest a low-inclination, low-eccentricity system with amodest impact from VHE γ-ray absorption due to pair production (τ ≲ 1 at 300 GeV) | en_US |
dc.language.iso | en | en_US |
dc.publisher | EDP Sciences | en_US |
dc.subject | X-rays: binaries | en_US |
dc.subject | gamma rays: stars | en_US |
dc.subject | stars: individual: 1FGL J1018.6-5856 | en_US |
dc.subject | radiation mechanisms: non-thermal | en_US |
dc.subject | acceleration of particles | en_US |
dc.title | Discovery of variable VHE γ-ray emission from the binary system 1FGL J1018.6-5856 | en_US |
dc.type | Article | en_US |
dc.contributor.researchID | 24420530 - Böttcher, Markus | |
dc.contributor.researchID | 13146629 - Davids, Isak Delberth | |
dc.contributor.researchID | 24790052 - Ivascenko, Alex | |
dc.contributor.researchID | 11749903 - Krüger, Petrus Paulus | |
dc.contributor.researchID | 22050574 - Pekeur, Nicolette Whilna | |
dc.contributor.researchID | 25161814 - Spanier, Felix Alexander | |
dc.contributor.researchID | 24922986 - Sushch, Iurii | |
dc.contributor.researchID | 10060499 - Van der Walt, Diederick Johannes | |
dc.contributor.researchID | 12006653 - Venter, Christo | |
dc.contributor.researchID | 20126999 - Seyffert, Albertus Stefanus | |