main idea: a paradox introduction: the gas of the cluster must cool down but the end product escape from detection
structure:
p1. the cooling flow
-the gas is primarily heated by the collapse of cluster and gives off x-rays
-the x-rays can't penetrate the earth' atmosphere and can't be observed by optical observers
-x-rays carry so much energy that the gas will cool down and settle into the cluster in the end
-the effects may bring trillions of new stars, a result calculated by the scientists
p2. 2 hypos of the phenomenon(no due result occur as calculated)
-black holes swallow the gas ?not even the biggest black hole is that massive.(否定词前置的部分倒装)
-the energy from the galaxy of cluster heat the gas and thus offset the effect of cooling flow ❓ whether the energy is enough to heat the gas
-left paradox
1 gas释放x光;光学望远镜观察不到,X光也穿不过大气层,只能依赖轨道上的天文台(observatory);X带走energy,以至于气体能稳定冷却在星系团中心【x-rays carry away so much energy that the gas should steadily cool off and settle into the center of the cluster】 ——cooling flows冷气流。 Flow:Effects:好多新星
2 唯一的麻烦:没人能找到(大量的冷气和新形成的新星)。如果是黑洞吞噬了他们,最大的黑洞也没这么大。也有人说flow不存在【 long-lasting outbursts of energy from the central galaxy of the cluster heated the gas enough to offset the radiative cooling星系团中心星系的持久的能量爆发使气体加热到足以抵消辐射冷却】,但爆发是否提供足够的能量分布在足够大的体积上,阻止冷气流。悖论:热团必冷却,但是冷却的最终产品the end of the product缺观察不到
主题:寻找cluster gas
结构:介绍hot gas 形成原理——提出问题:找不到——叙述进度:F的探索——进度2:T的探索
主要内容
P1
由cluster因引力collapse而加热的gas会放射出X光。完美地望远镜探测不到这些光线,它们也没法闯过地球的大气层,隐私我们只能靠环球卫星来discover。20年前NASA的X光探测仪和其他仪器发现X光携带大量energy,以至于那团gas会cool off然后settle into the centre of the culster——“cool flow”.
F开始用这届一起继续研究flows。他认为这些flows由巨大影响。如果他们呢存在了十亿年,那么它们将会散发出几百亿个新的stars。
P2
唯一的问题都是没有人能找到他们。observers在做无用功。如果黑洞把他们吸收了,那应该质量也会增加很多,但实际测试并没有发现黑洞的质量有很大的变化。
T认为这些长时间大范围的flows是不存在的。可能的解释是是gas be heated的爆发出来的energy已经足以让flows offset the radiative cooling。radio 宇航员也一直在为这个解释做研究。
但是问题又出现了:爆发出的energy有没有平均分配到足以使整个flows呢?
so, the paradox remained: he hot cluste rgas must cool, but the end product of the cooling mysterious escaped detection.
245 black hole blowback
P1: cluster collapse heat gas, gas give off x-rays, and discovery and study of this gas depend on orbiting observations. X-rays“cooling flow”has dramatic effects if they persist billion years, the deposited gas could form trillions of new stars.
P2: trouble: can not find them. Not black hole swallow them all. Or T:cooling flow do not exist. Paradox remained( the end product of the cooling)