Features of collisionless turbulence in the intracluster medium from simulated Faraday Rotation maps

Autor(es)

Nakwacki, M. S. ^{[1, 2]} ; Kowal, G. ^{[3, 4]} ; Santos-Lima, R. ^[5] ; de Gouveia Dal Pino, E. M. ^[5] ; Falceta-Goncalves, D. A. ^{[6, 3]}

Afiliação do(s) autor(es)

^[1] Univ Buenos Aires, Fac Ciencias Exactas & Nat, RA-1053 Buenos Aires, DF - Argentina

^[2] UBA CONICET, Inst Astron & Fis Espacio, Buenos Aires, DF - Argentina

^[3] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, Sao Paulo, SP - Brazil

^[4] Univ Cruzeiro Sul, Nucleo Astrofs Ter, Sao Paulo, SP - Brazil

^[5] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Sao Paulo, SP - Brazil

^[6] Univ St Andrews, Sch Phys & Astron, SUPA, St Andrews KY16 9SS, Fife - Scotland

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 455, n. 4, p. 3702-3723, FEB 1 2016.
• Citações Web of Science: 4

Resumo

Observations of the intracluster medium (ICM) in galaxy clusters suggest for the presence of turbulence and the magnetic fields' existence has been proved through observations of Faraday Rotation (FR) and synchrotron emission. The ICM is also known to be filled by a rarefied weakly collisional plasma. In this work, we study the possible signatures left on FR maps by collisionless instabilities. For this purpose, we use a numerical approach to investigate the dynamics of the turbulence in collisionless plasmas based on an magnetohydrodynamical (MHD) formalism taking into account different levels of pressure anisotropy. We consider models covering the sub/super-Alfvenic and trans/supersonic regimes, one of them representing the fiducial conditions corresponding to the ICM. From the simulated models, we compute FR maps and analyse several statistical indicators in order to characterize the magnetic field structure and compare the results obtained with the collisionless model to those obtained using standard collisional MHD framework. We find that important imprints of the pressure anisotropy prevails in the magnetic field and also manifest in the associated FR maps which evidence smaller correlation lengths in the collisionless MHD case. These points are remarkably noticeable for the case mimicking the conditions prevailing in ICM. Nevertheless, in this study we have neglected the decrease of pressure anisotropy due to the feedback of the instabilities that naturally arise in collisionless plasmas at small scales. This decrease may not affect the statistical imprint differences described above, but should be examined elsewhere. (AU)

• Processo FAPESP: 13/10559-5 - Investigação de fenômenos de altas energias e plasmas astrofísicos: teoria, simulações numéricas, observações e desenvolvimento de instrumentação para o Cherenkov Telescope Array (CTA)
• Beneficiário: Elisabete Maria de Gouveia Dal Pino
• Modalidade de apoio: Auxílio à Pesquisa - Projetos Especiais
• Processo FAPESP: 13/18815-0 - Reconexão magnética e processos relacionados em plasmas astrofísicos colisionais e acolisionais: das chamas solares para fontes extragaláticas
• Beneficiário: Grzegorz Kowal
• Modalidade de apoio: Bolsas no Brasil - Jovens Pesquisadores
• Processo FAPESP: 13/15115-8 - Estudo de efeitos de plasma não-colisional: aplicação ao meio intra-aglomerado de galáxias
• Beneficiário: Reinaldo Santos de Lima
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 13/04073-2 - Reconexão magnética e processos relacionados em plasmas astrofísicos colisionais e acolisionais: das chamas solares para fontes extragaláticas
• Beneficiário: Grzegorz Kowal
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 10/50298-8 - Kinetic magnetohydrodynamics and astrophysical collisionless plasmas
• Beneficiário: Maria Soledad Nakwacki
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 09/50053-8 - Magnetic reconnection and particle acceleration in astrophysical sources and diffuse media
• Beneficiário: Grzegorz Kowal
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado