Paul Scherrer Institut Laboratory for Astrophysics (LAP)

Paul Scherrer Institut
CH-5232 Villigen PSI
Phone +41 56 310 21 11
Fax +41 56 310 21 99


 

 

    
    LAP Home


    Astrophysics


    Space Research

      Current Activities

          MIRI-JWST

          EURECA-XEUS

        POLAR

          LEED

      Previous Projects

          RGS-XMM

          REM

          FUVITA-SRG

          SREM

          RHESSI


     Satellite Projects


    User Facilities


    

 

    News and Events


     Reports 


     Seminars


    Members


    Positions


    Contact




     

Google


WWW psi.ch


Updated:
23.03.2005
E-Mail: wojtek.hajdas@psi.ch


Printer Friendly Printout without Logo or Navigation Elements available here... just click and print

PSI Server Side Include SSI Information - to remove, set SSIINFO to execute with No in your /ssi/projectvariables.shtml


Hard X-ray polarimeter detector POLAR 

 

Discovered 35 years ago, Gamma Ray Bursts (GRB) remain a challenging issue
and one of the most interesting topics in astrophysics. The genuine character
of the GRB sources and the energy release mechanisms still remain a mystery
and there are several competing theoretical models and mechanisms trying to
explain it.

The launch of several high energy observatories with powerful instruments
on board (XMM, Integral, RHESSI, BeppoSax) and of advanced GRB detectors
(CGRO, HETE2) made possible a number of new discoveries and in
parallel noteworthy theoretical progresses. However the instruments advances
were mainly on effective area, energy and angular resolution, while very little
progress was achieved on polarization measurement, partly due to the experimental
difficulty of measuring polarization. Today, photon polarization turns  out to be one
of the ultimate observables required to make a clear distinction between different
theoretical models in order to fully understand the GRB nature.

To date however, the polarization was explored only in a few afterglow
measurements in visible light. The recent reports of a high linear polarization (80+-20%)
 in the prompt emission of GRB021206, together with its subsequent revisions as too
preliminary (if not mistaken) , demonstrated that polarimetric measurements are difficult
and need dedicated instruments. Such measurements are a must in the era of missions
like SWIFT or the forthcoming GLAST experiment.

Both SWIFT and GLAST can promptly determine the exact GRB coordinates
as well as the light-curve and spectral characteristics. For such bursts the the
polarimetric detectors will bring simultaneously additional unique information
about the magnetic field structure and dynamics during the prompt gamma
ray emission. We propose here a dedicated instrument with high sensitivity
for polarization measurements.

Poster presented during the ESA Cosmic Vision 2005 meeting in Noordwijk (ESA-ESTEC)