IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Aspect angle for interstellar magnetic field in SN 1006
Autor/es:
PETRUK, O.; DUBNER, G.; CASTELLETTI, G.; BOCCHINO, F.; IAKUBOVSKYI, D.; KIRSCH, M. G. F.; MICELI, M.; ORLANDO, S.; TELEZHINSKY, I.
Revista:
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Editorial:
Blackwell Publishing
Referencias:
Lugar: Oxford, UK; Año: 2009 vol. 393 p. 1034 - 1040
ISSN:
0035-8711
Resumen:
A number of important processes taking place around strong shocks in
supernova remnants (SNRs) depend on the shock obliquity. The measured
synchrotron flux is a function of the aspect angle between interstellar
magnetic field (ISMF) and the line of sight. Thus, a model of
non-thermal emission from SNRs should account for the orientation of the
ambient magnetic field. We develop a new method for the estimation of
the aspect angle, based on the comparison between observed and
synthesized radio maps of SNRs, making different assumptions about the
dependence of electron injection efficiency on the shock obliquity. The
method uses the azimuthal profile of radio surface brightness as a probe
for orientation of ambient magnetic field because it is almost
insensitive to the downstream distribution of magnetic field and
emitting electrons. We apply our method to a new radio image of SN 1006
produced on the basis of archival Very Large Array and Parkes data. The
image recovers emission from all spatial structures with angular scales
from a few arcsec to 15arcmin. We explore different models of injection
efficiency and find the following best-fitting values for the aspect
angle of SN 1006: φo = 70o +/-
4.2o if the injection is isotropic, φo =
64o +/- 2.8o for quasi-perpendicular injection
(SNR has an equatorial belt in both cases) and φo =
11o +/- 0.8o for quasi-parallel injection
(polar-cap model of SNR). In the last case, SN 1006 is expected to have
a centrally peaked morphology contrary to what is observed. Therefore,
our analysis provides some indication against the quasi-parallel
injection model.