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تسجيل مستخدم جديدMAGIC reveals a complex morphology within the unidentified gamma-ray source HESS J1857+026
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HESS J1857+026 is an extended TeV gamma-ray source that was discovered by H.E.S.S. as part of its Galactic plane survey. Given its broadband spectral energy distribution and its spatial coincidence with the young energetic pulsar PSR J1856+0245, the source has been put forward as a pulsar wind nebula (PWN) candidate. MAGIC has performed follow-up observations aimed at mapping the source down to energies approaching 100 GeV in order to better understand its complex morphology. HESS J1857+026 was observed by MAGIC in 2010, yielding 29 hours of good quality stereoscopic data that allowed us to map the source region in two separate ranges of energy. We detected very-high-energy gamma-ray emission from HESS J1857+026 with a significance of $12 sigma$ above $150$ GeV. The differential energy spectrum between $100$ GeV and $13$ TeV is well described by a power law function $dN/dE = N_0(E/1textrm{TeV})^{-Gamma}$ with $N_0 = (5.37 pm0.44_{stat} pm1.5_{sys}) times 10^{-12} (textrm{TeV}^{-1} textrm{cm}^{-2}$ $textrm{ s}^{-1})$ and $Gamma = 2.16pm0.07_{stat} pm0.15_{sys}$, which bridges the gap between the GeV emission measured by Fermi-LAT and the multi-TeV emission measured by H.E.S.S.. In addition, we present a detailed analysis of the energy-dependent morphology of this region. We couple these results with archival multi-wavelength data and outline evidence in favor of a two-source scenario, whereby one source is associated with a PWN, while the other could be linked with a molecular cloud complex containing an HII region and a possible gas cavity.
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We investigate the physical nature and origin of the gamma-ray emission from the extended source HESS J1841-055 observed at TeV and GeV energies. We observed HESS J1841-055 at TeV energies for a total effective time of 43 hours with the MAGIC telesco
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The nature of the gamma-ray source HESS J1507-622 that is located significantly off-set from the Galactic plane is not ascertained to date. Identifying the environment of an enigmatic object may help to constrain its nature. The path of the line of s
ight of HESS J1507-622 through the Galaxy is compared to the characteristic length scales of stellar populations of different ages. Furthermore, for this object, the energy density in particles is contrasted to the magnetic field energy density and constraints on the distance based on equipartition between these two components are calculated. The line of sight of HESS J1507-622 reaches a minimum distance to the Galactic center at around a galactocentric distance of 5.3 kpc at about 300 pc off the Galactic disc. This location coincides with the scale length and width of stars with an age of 1.2 Gyr which could in principle be an indication that HESS J1507-622 is connected to a stellar population of similar age. For such a case the source appears to be strongly particle dominated. In a leptonic scenario, if a magnetic field in the source of 1 $mu$G is assumed, equipartition between magnetic field and particles would be realized at a distance of >1 Mpc. This could indicate an extragalactic origin of this object. However, an extragalactic origin is challenged by the extension of the source. The environment of HESS J1507-622 still remains elusive. For the case where this source belongs to a new class of gamma-ray emitters, the distribution of related objects (if existing) may help to settle the respective environment and distance scale.
The nature of the first unidentified VHE gamma-ray source with significant angular offset from the Galactic plane of 3.5 degrees, HESS J1507-622, is explored. Fermi-LAT data in the high-energy (HE, 100 MeV < E < 100 GeV) gamma-ray range collected ove
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