Bibcode
MAGIC Collaboration; Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; de Oña Wilhelmi, E.; di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Griffiths, S.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Oramas, A.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Munar-Adrover, P.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K. et al.
Referencia bibliográfica
Astronomy and Astrophysics, Volume 612, id.A14, 8 pp.
Fecha de publicación:
4
2018
Revista
Número de citas
29
Número de citas referidas
23
Descripción
Context. The large jet kinetic power and non-thermal processes occurring
in the microquasar SS 433 make this source a good candidate for a very
high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes above the
sensitivity limits of current Cherenkov telescopes have been predicted
for both the central X-ray binary system and the interaction regions of
SS 433 jets with the surrounding W50 nebula. Non-thermal emission at
lower energies has been previously reported, indicating that efficient
particle acceleration is taking place in the system. Aim. We explore the
capability of SS 433 to emit VHE gamma rays during periods in which the
expected flux attenuation due to periodic eclipses (Porb
13.1 days) and precession of the circumstellar disk (Ppre
162 days) periodically covering the central binary system is expected to
be at its minimum. The eastern and western SS 433/W50 interaction
regions are also examined using the whole data set available. We aim to
constrain some theoretical models previously developed for this system
with our observations. Methods: We made use of dedicated
observations from the Major Atmospheric Gamma Imaging Cherenkov
telescopes (MAGIC) and High Energy Spectroscopic System (H.E.S.S.) of SS
433 taken from 2006 to 2011. These observation were combined for the
first time and accounted for a total effective observation time of 16.5
h, which were scheduled considering the expected phases of minimum
absorption of the putative VHE emission. Gamma-ray attenuation does not
affect the jet/medium interaction regions. In this case, the analysis of
a larger data set amounting to 40-80 h, depending on the region, was
employed. Results: No evidence of VHE gamma-ray emission either
from the central binary system or from the eastern/western interaction
regions was found. Upper limits were computed for the combined data set.
Differential fluxes from the central system are found to be ≲
10-12-10-13 TeV-1 cm-2
s-1 in an energy interval ranging from few × 100 GeV
to few TeV. Integral flux limits down to
10-12-10-13 ph cm-2 s-1 and
10-13-10-14 ph cm-2 s-1 are
obtainedat 300 and 800 GeV, respectively. Our results are used to place
constraints on the particle acceleration fraction at the inner
jetregions and on the physics of the jet/medium interactions.
Conclusions: Our findings suggest that the fraction of the jet kinetic
power that is transferred to relativistic protons must be relatively
small in SS 433, qp ≤ 2.5 × 10-5, to
explain the lack of TeV and neutrino emission from the central system.
At the SS 433/W50 interface, the presence of magnetic fields ≳10
μG is derived assuming a synchrotron origin for the observed X-ray
emission. This also implies the presence of high-energy electrons with
Ee- up to 50 TeV, preventing an efficient
production of gamma-ray fluxes in these interaction regions.
Proyectos relacionados
Astrofísica de Partículas
El Grupo de Astrofísica de Partículas del IAC participa activamente en tres grandes colaboraciones internacionales de astrofísica de muy altas energías: AMS (Alpha Magnetic Spectrometer), los telescopios de radiación Cherenkov MAGIC I y II, y el Cherenkov Telescope Array (CTA). AMS es un detector de partículas diseñado para operar en el espacio, a
Ramón
García López