Speaker
Dr
Jaroslaw Dyks
(Nicolaus Copernicus Astronomical Center)
Description
The knowledge of radio emission geometry is crucial
for interpreting their gamma-ray profiles, and for
establishing the orientation of their tilted magnetic field.
I will review the continually increasing evidence against the most popular (nested cone) radio beam geometry.
It will be shown that several features of pulse profiles,
which have normally been considered as signatures of the nested cones,
can in fact be readily interpreted through a system of fan beams.
These include some properties of the radius-to-frequency mapping
as well as the special-relativistic lag of the core component in
multicomponent profiles.
A new statistical probe of beam shape will be introduced,
based on the ratio of component separations
observed in M and Q profiles. This method is independent of the parameters
that determine the scale of the beam (emission altitude, frequency,
rotation period, dipole tilt) while it retains the sensitivity to the
beam shape. When applied to the Q and M pulse profiles,
the method reinforces the problems of the conal geometry and favours
the azimuthally-structured beam (a system of fan beams).
The non-conal geometry has consequences for the gamma-ray profile modelling.
| Collaboration | B. Rudak, M. Pierbattista, L. Saha |
|---|
Author
Dr
Jaroslaw Dyks
(Nicolaus Copernicus Astronomical Center)
