12-20 July 2017
BEXCO
Asia/Seoul timezone
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Contribution

BEXCO - Room F(201/202/203/204)

[GA312] H.E.S.S. II observations of PSR B1259-63's 2014 periastron passage

Speakers

  • Carlo ROMOLI

Primary authors

Co-authors

Description

PSR B1259-63 is a gamma-ray binary system composed of an O9.5Ve main sequence star, LS 2883, and a 47.8ms spinning neutron star orbiting it every 3.4 years in a highly eccentric orbit (e = 0.87). PSR B1259-63 is so far the only gamma-ray binary in which the compact object has been firmly identified. H.E.S.S. observed this system during its periastron passage in 2004, 2007, 2011 and 2014. Fort this latter event, a detailed campaign was organised making use of the new capabilities of H.E.S.S.II, in particular its improved sensitivity and a lower analysis energy threshold. This campaign covered for the first time the exact time of periastron and parts of the orbit so far unexplored at VHE energies, and included as well observations during the GeV flare observed contemporaneously with the Fermi-LAT. The analysis of the H.E.S.S. II data indicate a relatively high TeV flux during this GeV flare, as well as at orbital phases preceding the first neutron star crossing of the circumstellar disk. These results will be summarised and discussed in the context of previous models attempting to explain the complex gamma-ray emission from this source.