سمینار این هفته را خانم آزاده مرادی نژاد دیزگاه از دانشکده فیزیک نظری دانشگاه ژنو ارائه خواهند کرد. عنوان و چکیدهٔ سمینار ایشان به شرح زیر است:

محاسبه افت خیزهای پس زمینه فرابنفش ناشی از خوشه بندی اختروش ها

(Ultraviolet background fluctuations with clustered sources) 

Abstract: Modeling helium reionization is challenging since a wide range of dynamical range is needed to account simultaneously for the scarcity and clustering of the sources and the physical properties of the low density intergalactic medium. Up to now several semi-analytic approaches have been developed that combine the analytical approaches with numerical simulations. Nevertheless several issues including the contribution of the quasar clustering to the variance of helium-ionizing fluctuations towards the end of the HeII reionization are still not settled. In this talk I will describe our analytical approach to this issue, which is based on the count-in-cells formalism. We demonstrate that an exact expression can be obtained if the clustering of the ionizing sources follows the hierarchical ansatz. In this case, quasar clustering contributes less than 30% to the variance of the intensity fluctuations for attenuation length less than 55 Mpc and the correlation length below 15 Mpc.

این سمینار در روز یکشنبه ۱۴ آذر ماه ۱۳۹۳، ساعت ۱۵ در کلاس فیزیک ۴ در طبقهٔ اول  دانشکدهٔ فیزیک برگزار خواهد شد.