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تسجيل مستخدم جديدالتوقيت والتصوير للذخائر المتصادمة: ما يكفي من الوقت والجاذبية لتسريع الرصاصة
Timing and Lensing of the Colliding Bullet Clusters: barely enough time and gravity to accelerate the bullet
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HongSheng Zhao
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نقدم محددات نظرية جزئية على الكمية الإجمالية للمادة الظلام في عقدة الرصاص المدمجة باستخدام الحوارات الزمنية لمجموعة المحلية التقليدية. نحن نعتبر أقواس الذرات في الأنظمة الجذرية التي تناسب بيانات الإشعاع. وتم العثور على أنظمة CDM متوافقة بشكل ضعيف في الجاذبية النيوتونية بإجمالي الشحنة M_{CDM} = 1 × 10 ^ {15} Msun من الظلام البارد: يمكن للشريحة الرصاصية التحرك بسرعة V_{DM} = 3000 كم / س، ويمكن لغاز الرصاص البارد التحرك بسرعة V_{gas} = 4200 كم / س. هذه هي تقريبًا أقصى سرعات التي يمكن تسارعها بواسطة الجاذبية لشريحتين من الظلام البارد في وقت هابل حتى بدون الضغط الشديد. وتنقض التوافق إذا اعتمدنا أعلى نهاية من مجموعات البيانات الخطأ لسرعة الغاز الرصاصي (5000-5400 كم / س)، ولن يكون الغاز الرصاصي مرتبطًا بشريحة العقدة لوقت هابل. وستطلب الأنظمة التي تحمل V_{DM} ~ 4500 كم / س ~ V_{gas} كمية غير واقعية كبيرة من CDM لعقدة تحتوي فقط على ~ 10 ^ {14} Msun من الغاز. يمكن تطبيق نتائجنا على أشياء أخرى بخارج الجاذبية العامة، على سبيل المثال، يمكن الحصول على سرعة $ 4500 كم / س بسهولة في نموذج الإشعاع الموندي المتأثر الفلاشي لأنجوس et al. (2007). ومع ذلك، يصعب التوافق مع بيانات الإشعاع والسرعة لنموذج MONDian مع قليل من الظلام البارد $ M_{HDM} le 0.6times 10 ^ {15} msun ونموذج CDM مع كتلة شريحة صغيرة $ le 1times 10 ^ {15} msun.
We present semi-analytical constraint on the amount of dark matter in the merging bullet galaxy cluster using the classical Local Group timing arguments. We consider particle orbits in potential models which fit the lensing data. {it Marginally consistent} CDM models in Newtonian gravity are found with a total mass M_{CDM} = 1 x 10^{15}Msun of Cold DM: the bullet subhalo can move with V_{DM}=3000km/s, and the bullet X-ray gas can move with V_{gas}=4200km/s. These are nearly the {it maximum speeds} that are accelerable by the gravity of two truncated CDM halos in a Hubble time even without the ram pressure. Consistency breaks down if one adopts higher end of the error bars for the bullet gas speed (5000-5400km/s), and the bullet gas would not be bound by the sub-cluster halo for the Hubble time. Models with V_{DM}~ 4500km/s ~ V_{gas} would invoke unrealistic large amount M_{CDM}=7x 10^{15}Msun of CDM for a cluster containing only ~ 10^{14}Msun of gas. Our results are generalisable beyond General Relativity, e.g., a speed of $4500kms$ is easily obtained in the relativistic MONDian lensing model of Angus et al. (2007). However, MONDian model with little hot dark matter $M_{HDM} le 0.6times 10^{15}msun$ and CDM model with a small halo mass $le 1times 10^{15}msun$ are barely consistent with lensing and velocity data.
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