Accueil > Séminaires d’Astrophysique > Probing relativistic jet physics with polarimetry of gamma-ray burst afterglows

 

Probing relativistic jet physics with polarimetry of gamma-ray burst afterglows

Klaas Wiersema (University of Leicester, UK) — au CESR

Par Francois RINCON - 30/09/2010

 

Séminaires d’Astrophysique

de l’Observatoire Midi-Pyrénées


Séminaire de

Klaas Wiersema

(University of Leicester, UK)

Jeudi 28 Octobre 2010 à 11h

CESR


Probing relativistic jet physics with polarimetry of gamma-ray burst afterglows

In the era of Swift, we have come to understand that both short and long gamma-ray bursts (GRBs) result from collimated relativistic outflows emanating from very deep potential wells, likely of newly formed black holes. The bright afterglows of GRBs are formed when these jets push relativistic blast waves into the ambient gas and are thus one of the few laboratories of particle acceleration in (collisionless) shocks, and relativistic MHD. Lightcurves and spectral energy distributions (SEDs) from radio- to X-ray frequencies are the most commonly used tools to study the properties of the blastwave. However, many questions remain unanswered : how are the relativistic particles that radiate the observed emission accelerated ? Where does the magnetic field in the shocked region come from ? What is its structure ? In addition, the lightcurves observed in the Swift era show a multitude of unexpected complexity, requiring modification of our theoretical understanding of afterglow physics. These modifications often are impossible to test with the lightcurves and SEDs we usually get. Polarimetry in optical and radio wavelengths provides vital additional diagnostics on the micro- and macro-physics of the afterglow, in particular the magnetic fields and energy distribution within the jets. I will show the most detailed linear- and circular polarimetric study of a Swift afterglow to date, obtained through our intensive VLT campaign. I will demonstrate the observational complexity of afterglow polarimetry, and the need to use the biggest telescopes available. In addition I will highlight the exciting possibilities of radio afterglow polarimetry with the SKA pathfinders (e.g. Lofar, MeerKAT).

 

 

[Page Précédente] [Dans la même rubrique] [Sommaire]

 

 

Site du CNRS Logo OMP
Logo UPS
Logo INSU-CNRS

Annuaire

Rechercher

Sur ce site



Bibliotheque

Laboratoire Astrophysique de Toulouse - Tarbes (UMR5572)

CNRS (Midi-Pyrénées)

Univ. Paul Sabatier

Liens utiles

Accueil Imprimer Contact mail Plan du site Crédits