Impact of the Cosmic Magnetic Field on the Formation of the Early Stars in the Universe

الموضوعات

علوم بحتة وطبيعية

الملخص

The investigation of the formation of the first stars in the Universe, termed Population III (Pop III), has until now largely neglected the impact of the cosmic magnetic field on their formation. Our present work focuses on the fragmentation properties of primordial protostellar discs and how they are modified by including magneto-hydrodynamic (MHD) aspects. We start from cosmological initial conditions at z = 100, then analyse the dynamics inside the most massive minihalo at a redshift close to z ~ 25. A magnetic field is inserted at an intermediate evolutionary stage, normalized to a fraction of the equipartition value. In order to explore the parameter space, different magnetic field geometries are considered including uniform, radial, toroidal, and poloidal configurations. The collapse of the gas is followed for ~8 orders of magnitude in density after the field was inserted, until a maximum of 10^15 cm^- 3 is reached. We find that the magnetic field leads to a delay in the collapse of the gas and inhibits the fragmentation of the emerging disc surrounding the central core. Moreover, the geometry of the field affects the collapse and the multiplicity of Pop III stars. The full understanding of the formation of these stars and their mass distribution thus needs to take into account the effect of magnetic fields. We further conclude that ideal MHD is only a first step in this endeavor, to be followed-up with a comprehensive treatment of dissipative effects, such as ambipolar diffusion and Ohmic dissipation. This is worth doing in future works.

روابط وملفات

التعريف والنوع

رقم الوثيقة

04a78d5c-bfce-4245-8fe8-c0d0765c839f

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

رسائل دكتوراة

نوع الملف

pdf text

أسماء الملفات

2326207_1.pdf

بيانات النشر

ألقاب المؤلفين

[{"name_ar":"Mounib El Eid","title_ar":"اشراف","title_en":"Supervision"},{"name_ar":"سينثيا ريموند سعد","title_ar":"اعداد","title_en":"Preparation"}]

اللغة

English

المصدر والدورية

اسم المصدر

Impact of the Cosmic Magnetic Field on the Formation of the Early Stars in the Universe

المحتوى والصفحات

عدد الصفحات

0

كلمات الباحثين

Show simple item record dc.contributor.advisor Touma, Jihad dc.contributor.author Saad, Cynthia dc.date.accessioned 2022-12-20T06:23:52Z dc.date.available 2022-12-20T06:23:52Z dc.date.issued 12/20/2022 dc.date.submitted 11/21/2022 dc.identifier.uri http://hdl.handle.net/10938/23772 dc.description.abstract The investigation of the formation of the first stars in the Universe, termed Population III (Pop III), has until now largely neglected the impact of the cosmic magnetic field on their formation. Our present work focuses on the fragmentation properties of primordial protostellar discs and how they are modified by including magneto-hydrodynamic (MHD) aspects. We start from cosmological initial con- ditions at z = 100, then analyse the dynamics inside the most massive minihalo at a redshift close to z ~ 25. A magnetic field is inserted at an intermediate evolutionary stage, normalized to a fraction of the equipartition value. In order to explore the parameter space, different magnetic field geometries are considered including uniform, radial, toroidal, and poloidal configurations. The collapse of the gas is followed for ~8 orders of magnitude in density after the field was inserted, until a maximum of 10^15 cm^- 3 is reached. We find that the magnetic field leads to a delay in the collapse of the gas and inhibits the fragmentation of the emerging disc surrounding the central core. Moreover, the geometry of the field affects the collapse and the multiplicity of Pop III stars. The full understanding of the formation of these stars and their mass distribution thus needs to take into account the effect of magnetic fields. We further conclude that ideal MHD is only a first step in this endeavor, to be followed-up with a comprehensive treatment of dissipative effects, such as ambipolar diffusion and Ohmic dissipation. This is worth doing in future works. dc.language.iso en dc.subject stars: formation dc.subject stars: Population III dc.subject ISM: magnetic fields dc.subject dark ages dc.subject reionization dc.subject first stars

إشراف وإعداد

الإشراف

Mounib El Eid

الإعداد

سينثيا ريموند سعد

الاقتباسات الببليوغرافية