Nonthermal processes and neutrino emission from the black hole GRO J0422+32 in a bursting state

¹ Instituto Argentino de Radioastronomía (IAR CCT La Plata, CONICET), C.C.5, (1984) Villa Elisa, Buenos Aires, Argentina
e-mail: fvieyro@iar-conicet.gov.ar
² Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
³ Departament d’Astronomia i Meteorologia, Institut de Ciències del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain

Received: 6 July 2012
Accepted: 22 August 2012

Abstract

Context. GRO J0422+32 is a member of the class of low-mass X-ray binaries (LMXBs). It was discovered during an outburst in 1992. During the entire episode a persistent power-law spectral component extending up to  ~1 MeV was observed, which suggests that nonthermal processes should have occurred in the system.

Aims. We study relativistic particle interactions and the neutrino production in the corona of GRO J0422+32, and explain the behavior of GRO J0422+32 during its recorded flaring phase.

Methods. We have developed a magnetized corona model to fit the spectrum of GRO J0422+32 during the low-hard state. We also estimate neutrino emission and study the detectability of neutrinos with 1 km³ detectors, such as IceCube.

Results. The short duration of the flares (~hours) and an energy cutoff around a few TeV in the neutrino spectrum make neutrino detection difficult. There are, however, many factors that can enhance neutrino emission.

Conclusions. The northern-sky coverage and full duty cycle of IceCube make it possible to detect neutrino bursts from objects of this kind through time-dependent analysis.