English

MAGIC reveals a complex morphology within the unidentified gamma-ray source HESS J1857+026

High Energy Astrophysical Phenomena 2014-11-19 v2

Abstract

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 12σ12 \sigma above 150150 GeV. The differential energy spectrum between 100100 GeV and 1313 TeV is well described by a power law function dN/dE=N0(E/1TeV)ΓdN/dE = N_0(E/1\textrm{TeV})^{-\Gamma} with N0=(5.37±0.44stat±1.5sys)×1012(TeV1cm2N_0 = (5.37 \pm0.44_{stat} \pm1.5_{sys}) \times 10^{-12} (\textrm{TeV}^{-1} \textrm{cm}^{-2}  s1)\textrm{ s}^{-1}) and Γ=2.16±0.07stat±0.15sys\Gamma = 2.16\pm0.07_{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.

Keywords

Cite

@article{arxiv.1401.7154,
  title  = {MAGIC reveals a complex morphology within the unidentified gamma-ray source HESS J1857+026},
  author = {MAGIC Collaboration and J. Aleksić and S. Ansoldi and L. A. Antonelli and P. Antoranz and A. Babic and P. Bangale and U. Barres de Almeida and J. A. Barrio and J. Becerra González and W. Bednarek and E. Bernardini and A. Biland and O. Blanch and S. Bonnefoy and G. Bonnoli and F. Borracci and T. Bretz and E. Carmona and A. Carosi and P. Colin and E. Colombo and J. L. Contreras and J. Cortina and S. Covino and P. Da Vela and F. Dazzi and A. De Angelis and G. De Caneva and B. De Lotto and C. Delgado Mendez and M. Doert and A. Domínguez and D. Dominis Prester and D. Dorner and M. Doro and S. Einecke and D. Eisenacher and D. Elsaesser and E. Farina and D. Ferenc and D. Fidalgo Carreto and M. V. Fonseca and L. Font and K. Frantzen and C. Fruck and R. J. García López and M. Garczarczyk and D. Garrido Terrats and M. Gaug and N. Godinović and A. González Muñoz and S. R. Gozzini and D. Hadasch and M. Hayashida and J. Herrera and A. Herrero and D. Hildebrand and J. Hose and D. Hrupec and W. Idec and V. Kadenius and H. Kellermann and S. Klepser and K. Kodani and Y. Konno and J. Krause and H. Kubo and J. Kushida and A. La Barbera and D. Lelas and N. Lewandowska and E. Lindfors and S. Lombardi and M. López and R. López-Coto and A. López-Oramas and E. Lorenz and I. Lozano and M. Makariev and K. Mallot and G. Maneva and N. Mankuzhiyil and K. Mannheim and L. Maraschi and B. Marcote and M. Mariotti and M. Martínez and D. Mazin and U. Menzel and M. Meucci and J. M. Miranda and R. Mirzoyan and A. Moralejo and P. Munar-Adrover and D. Nakajima and A. Niedzwiecki and K. Nilsson and K. Nishijima and K. Noda and N. Nowak and E. de Oña Wilhelmi and R. Orito and A. Overkemping and S. Paiano and M. Palatiello and D. Paneque and R. Paoletti and J. M. Paredes and X. Paredes-Fortuny and S. Partini and M. Persic and F. Prada and P. G. Prada Moroni and E. Prandini and S. Preziuso and I. Puljak and R. Reinthal and W. Rhode and M. Ribó and J. Rico and J. Rodriguez Garcia and S. Rügamer and A. Saggion and T. Saito and K. Saito and K. Satalecka and V. Scalzotto and V. Scapin and C. Schultz and T. Schweizer and S. N. Shore and A. Sillanpää and J. Sitarek and I. Snidaric and D. Sobczynska and F. Spanier and V. Stamatescu and A. Stamerra and T. Steinbring and J. Storz and M. Strzys and S. Sun and T. Surić and L. Takalo and H. Takami and F. Tavecchio and P. Temnikov and T. Terzić and D. Tescaro and M. Teshima and J. Thaele and O. Tibolla and D. F. Torres and T. Toyama and A. Treves and M. Uellenbeck and P. Vogler and R. M. Wagner and F. Zandanel and R. Zanin},
  journal= {arXiv preprint arXiv:1401.7154},
  year   = {2014}
}

Comments

9 pages, 6 figures. Accepted for publication in A&A

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