MAGIC observation of the GRB080430 afterglow
Creators: name: MAGIC Collaboration
name: Aleksić, J.
name: Anderhub, H.
name: Antonelli, L. A.
name: Antoranz, P.
name: Backes, M.
name: Baixeras, C.
name: Balestra, S.
name: Barrio, J. A.
name: Bastieri, D.
name: González, J. Becerra
name: Becker, J. K.
name: Bednarek, W.
name: Berdyugin, A.
name: Berger, K.
name: Bernardini, E.
name: Biland, A.
name: Bock, R. K.
name: Bonnoli, G.
name: Bordas, P.
name: Tridon, D. Borla
name: Bosch-Ramon, V.
name: Bose, D.
name: Braun, I.
name: Bretz, T.
name: Britzger, D.
name: Camara, M.
name: Carmona, E.
name: Carosi, A.
name: Colin, P.
name: Commichau, S.
name: Contreras, J. L.
name: Cortina, J.
name: Costado, M. T.
name: Covino, S.
name: Dazzi, F.
name: De Angelis, A.
name: del Pozo, E. de Cea
name: Reyes, R. De los
name: De Lotto, B.
name: De Maria, M.
name: De Sabata, F.
name: Mendez, C. Delgado
name: Doert, M.
name: Domínguez, A.
name: Prester, D. Dominis
name: Dorner, D.
name: Doro, M.
name: Elsaesser, D.
name: Errando, M.
name: Ferenc, D.
name: Fernández, E.
name: Firpo, R.
name: Fonseca, M. V.
name: Font, L.
name: Galante, N.
name: López, R. J. García
name: Garczarczyk, M.
name: Gaug, M.
name: Godinovic, N.
name: Goebel, F.
name: Hadasch, D.
name: Herrero, A.
name: Hildebrand, D.
name: Höhne-Mönch, D.
name: Hose, J.
name: Hrupec, D.
name: Hsu, C. C.
name: Jogler, T.
name: Klepser, S.
name: Krähenbühl, T.
name: Kranich, D.
name: La Barbera, A.
name: Laille, A.
name: Leonardo, E.
name: Lindfors, E.
name: Lombardi, S.
name: Longo, F.
name: López, M.
name: Lorenz, E.
name: Majumdar, P.
name: Maneva, G.
name: Mankuzhiyil, N.
name: Mannheim, K.
name: Maraschi, L.
name: Mariotti, M.
name: Martínez, M.
name: Mazin, D.
name: Meucci, M.
name: Miranda, J. M.
name: Mirzoyan, R.
name: Miyamoto, H.
name: Moldón, J.
name: Moles, M.
name: Moralejo, A.
name: Nieto, D.
name: Nilsson, K.
name: Ninkovic, J.
name: Orito, R.
name: Oya, I.
name: Paoletti, R.
name: Paredes, J. M.
name: Pasanen, M.
name: Pascoli, D.
name: Pauss, F.
name: Pegna, R. G.
name: Perez-Torres, M. A.
name: Persic, M.
name: Peruzzo, L.
name: Prada, F.
name: Prandini, E.
name: Puchades, N.
name: Puljak, I.
name: Reichardt, I.
name: Rhode, W.
name: Ribó, M.
name: Rico, J.
name: Rissi, M.
name: Rügamer, S.
name: Saggion, A.
name: Saito, T. Y.
name: Salvati, M.
name: Sánchez-Conde, M.
name: Satalecka, K.
name: Scalzotto, V.
name: Scapin, V.
name: Schweizer, T.
name: Shayduk, M.
name: Shore, S. N.
name: Sierpowska-Bartosik, A.
name: Sillanpää, A.
name: Sitarek, J.
name: Sobczynska, D.
name: Spanier, F.
name: Spiro, S.
name: Stamerra, A.
name: Steinke, B.
name: Strah, N.
name: Struebig, J. C.
name: Suric, T.
name: Takalo, L.
name: Tavecchio, F.
name: Temnikov, P.
name: Tescaro, D.
name: Teshima, M.
name: Torres, D. F.
name: Turini, N.
name: Vankov, H.
name: Wagner, R. M.
name: Zabalza, V.
name: Zandanel, F.
name: Zanin, R.
name: Zapatero, J.
name: de Ugarte-Postigo, A.
Publisher: name: arXiv
Year: 2010
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Context: Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of gamma-ray bursts during the prompt phase, i.e. the initial burst of high-energy radiation, and during the long-lasting afterglows. In spite of many successes in interpreting these phenomena, there are still several open key questions about the fundamental emission processes, their energetics and the environment. Aim: Independently of specific gamma-ray burst theoretical recipes, spectra in the GeV/TeV range are predicted to be remarkably simple, being satisfactorily modeled with power-laws, and therefore offer a very valuable tool to probe the extragalactic background light distribution. Furthermore, the simple detection of a component at very-high energies, i.e. at $\sim 100$\,GeV, would solve the ambiguity about the importance of various possible emission processes, which provide barely distinguishable scenarios at lower energies. Methods: We used the results of the MAGIC telescope observation of the moderate resdhift ($z\sim0.76$) \object{GRB\,080430} at energies above about 80\,GeV, to evaluate the perspective for late-afterglow observations with ground based GeV/TeV telescopes. Results: We obtained an upper limit of $F_{\rm 95%\,CL} = 5.5 \times 10^{-11}$\,erg\,cm$^{-2}$\,s$^{-1}$ for the very-high energy emission of \object{GRB\,080430}, which cannot set further constraints on the theoretical scenarios proposed for this object also due to the difficulties in modeling the low-energy afterglow. Nonetheless, our observations show that Cherenkov telescopes have already reached the required sensitivity to detect the GeV/TeV emission of GRBs at moderate redshift ($z \lesssim 0.8$), provided the observations are carried out at early times, close to the onset of their afterglow phase.
description: 6 pages, 1 figure. Astronomy &amp; Astrophysics, in press. Revision affects only the author list.