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تسجيل مستخدم جديدصنع المجرات في سياق كوسمولوجي: الحاجة إلى ردود الفعل النجمية المبكرة
Making Galaxies in a Cosmological Context: The Need for Early Stellar Feedback
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تأليف
G. Stinson
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نقدم برنامج Making Galaxies in a Cosmological Context (MaGICC) للمحاكاة بطريقة الذبابات الجزيئية المنعكسة (SPH). نصفح عن دراسة المعلمات لمحاكاة تشكيل المجرات لمجرة L* تستخدم الانفعال النجمي المبكر مع الانفعال النجوم الشعاعي لتطابق علاقة الكتلة النجمية والكتلة الهالية. على الرغم من أن الانفعال النجوم الشعاعي يمكن أن يقلل من التشكيل النجمي كافياً لتطابق علاقة الكتلة النجمية والكتلة الهالية، فإن المجرة تشكل الكثير من النجوم قبل z = 2 لتطابق التطور المرئي باستخدام التطابق الغذائي. يعمل الانفعال النجمي المبكر الخاص بنا بشكل حراري فقط وبالتالي يعمل كمصدر للايونيزاسيون كذلك كمصدر للضغط الإضافي من الإشعاع الناتج من النجوم الشابة الكبيرة. يحرك الانفعال المبكر الحرارة إلى > 10 ^ 6 K قبل التبريد إلى 10 ^ 4 K. ينشأ الضغط من هذا الغاز الساخن دفقاً أكثر واسعاً ويمنع المزيد من التشكيل النجمي قبل z = 1 من أجل الانفعال النجوم الشعاعي فقط. يحتوي الدفق الناتج على مجرة بدوران مستقر، وملخص سطح السطوع الأسيوي، ويطابق العديد من علاقات الدفق التالية. ينشأ الدفق من الداخل إلى الخارج مع طول مكعب الأسيوي الزائد كما يتطور المجرة. في المجمل، يساعد الانفعال النجمي المبكر في محاكاة المجاري التي تطابق النتائج المرئية في الأحمر الداكن والأحمر المتأخر.
We introduce the Making Galaxies in a Cosmological Context (MaGICC) program of smoothed particle hydrodynamics (SPH) simulations. We describe a parameter study of galaxy formation simulations of an L* galaxy that uses early stellar feedback combined with supernova feedback to match the stellar mass--halo mass relationship. While supernova feedback alone can reduce star formation enough to match the stellar mass--halo mass relationship, the galaxy forms too many stars before z=2 to match the evolution seen using abundance matching. Our early stellar feedback is purely thermal and thus operates like a UV ionization source as well as providing some additional pressure from the radiation of massive, young stars. The early feedback heats gas to >10^6 K before cooling to 10^4 K. The pressure from this hot gas creates a more extended disk and prevents more star formation prior to z=1 than supernovae feedback alone. The resulting disk galaxy has a flat rotation curve, an exponential surface brightness profile, and matches a wide range of disk scaling relationships. The disk forms from the inside-out with an increasing exponential scale length as the galaxy evolves. Overall, early stellar feedback helps to simulate galaxies that match observational results at low and high redshifts.
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