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哈勃太空望远镜探测到矮星系的“保护罩”:麦哲伦日冕_我的网站

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一 |     HHS Secretary Xavier Becerra answered questions at a Tuesday press conference following the overturning of Roe v. Wade, the landmark Supreme Court decision that protected the constitutional right to abortion.,"Friday's Supreme Court decision was despicable. But it was not unpredictable. HHS has been preparing for this for some time," he began.,“FDA has found medication abortion treatments like mifepristone safe and effective,” said Becerra, who preempted his answer to press questions by saying that he would answer well enough while “stay[ing] in the legal confines.”,Women Hoarding Birth Control, Abortion Pills After Roe v Wade Overturned, Media SaysYesterday, 18:18 GMT,“Those medications that may be classified as medication abortion that the FDA has approved as safe and effective are therefore available for prescription,” explained Becerra, before adding that he can’t say what precisely “that means” because the HHS is trying to stay within the “confines of the law.”,“Even though it’s a law that I personally believe jeopardizes the health of women, we will stay within the confines of the law,” said Becerra.,As for the legal conditions under which the abortion pill can be prescribed, Becerra’s cautious response to reporters and Americans was to “stay tuned.”,Becerra did provide some hope on the issue of abortion care for pro-choice advocates and women’s health care providers like Planned Parenthood, which says exclusion from state family planning programs violates federal law. He explained that if a state is using federal funding for healthcare programs, they must respect laws at the federal level even when those services provide abortion care.,VP Kamala Harris Did Not Believe Justices When They Said Roe Was SettledYesterday, 23:31 GMT,Becerra added that the White House isn’t interested in “going rogue” and providing Americans with abortion services.,"We're not interested in going rogue and doing things just because we want to make sure what we tell Americans is accurate—because we hear, we know, a lot Americans are hearing a lot of inaccurate information," Becerra replied after ABC’s Mary Bruce asked him why the White House’s proposals weren’t more prepared for the fall of Roe v. Wade if they had been expecting it.,"And so to every American who's impacted: My apologies that, as I said, we can't tell you there's a silver bullet. But what I am saying to you is that the more we dig, we will do everything we can with what we find to make sure we're protecting women's reproductive health care services. It takes a little time because we want to do it right, and we want to do it according to the law.",On Friday, Attorney General Merrick Garland announced that “states may not ban” abortion pills that are approved by the FDA. However, he failed to explain how the FDA could ensure access to abortion pills such as mifepristone.。    最近的理论预测表明,这些矮小的卫星星系必须受到一个无孔不入的防护罩的保护,以防止银河系将其基本的恒星形成气体移除。

二 | 这种所谓的麦哲伦日冕,由温度为50万度的超强气体组成,将作为麦哲伦云周围的一种宇宙碰撞区,使圆盘和恒星在碰撞中相对不受伤害。

三 | 尽管模拟显示麦哲伦日冕应该存在,但观察到的证据仍然难以找到。利用哈勃太空望远镜和远紫外光谱探测器独特的紫外线视野,加上遥远的类星体的探测能力,天文学家终于能够探测到麦哲伦日冕并开始绘制其地图。这个由热气体组成的弥漫性光环的发现,从大麦哲伦云延伸出10万光年,覆盖了南部天空的大部分,证实了这个预测。

四 | 它还照亮了我们对小星系如何与大星系互动而不失去未来恒星形成所需燃料的理解。

五 | 距离地球近20万光年的大麦哲伦星系是银河系的一个卫星星系,它漂浮在太空中,围绕着我们的银河系跳着漫长而缓慢的舞蹈。当银河系的引力轻柔地拉扯着它邻居的气体云时,它们就会坍塌,形成新的恒星。反过来,这些恒星又将气体云照亮,呈现出万花筒般的色彩,在这张来自美国宇航局/欧空局哈勃太空望远镜的图像中可以看到。几十亿年来,大麦哲伦云和小麦哲伦云--银河系最大的卫星星系一直遵循着一个危险的旅程。

六 | 当它们被拉向我们的母星系时,它们相互绕行,开始解体,留下了气态碎片的痕迹。然而,这些矮星系仍然完好无损,持续进行着旺盛的恒星形成,让天文学家们大惑不解。很多人都在努力解释这些物质流怎么可能存在,如果这些气体被从这些星系中移除,它们怎么还能形成恒星呢?由Krishnarao领导的一个天文学家小组终于找到了答案,在美国宇航局哈勃太空望远镜和一颗名为远紫外光谱探测器(FUSE)的退役卫星的数据帮助下,他们发现麦哲伦星系被一个日冕所包围,这是一个由高温超强气体组成的保护罩。这将这两个星系包裹起来,防止它们的气体供应被银河系抽走,从而使它们能够继续形成新的恒星。这一发现刚刚于9月28日发表在《自然》杂志上,涉及到星系演化的一个新方面。马里兰州巴尔的摩太空望远镜科学研究所的共同研究者安德鲁-福克斯说:"星系将自己包裹在气态的茧中,作为对其他星系的防御性盾牌。

七 | "几年前,天文学家预测了日冕的存在。"我们发现,如果我们在模拟麦哲伦云落入银河系的过程中加入日冕,我们就可以首次解释提取气体的质量,"威斯康星大学麦迪逊分校的共同研究者埃琳娜-德翁吉亚解释说。

八 | "我们知道,大麦哲伦云应该有足够大的质量来拥有一个日冕"。然而,虽然覆盖了南部天空的很大一部分,并从麦哲伦云延伸到10万光年以上,但日冕实际上是看不见的。

九 | 事实上,绘制它需要从30年的存档数据中搜寻合适的测量数据。科学家们认为,星系的日冕是数十亿年前坍缩形成星系的原始气体云的残留物。尽管在更遥远的矮星系周围已经看到了日冕,但天文学家以前从未能够像这样详细地探测一个日冕。Krishnarao说:"在计算机模拟中,有很多关于它们应该是什么样子的预测,它们在数十亿年中应该如何互动,但是在观测中,我们无法真正测试其中的大部分,因为矮星系通常太难探测了。

十 | 因为它们就在我们家门口,麦哲伦云提供了一个研究矮星系如何互动和演变的绝佳机会。"为了寻找麦哲伦日冕的直接证据,研究小组在哈勃和FUSE档案中筛选了位于麦哲伦日冕后面数十亿光年的类星体的紫外线观测。类星体是星系中极其明亮的核心,其中含有大量活跃的黑洞。尽管科学家们推断,尽管日冕会太暗而无法单独看到,但他们认为,它应该作为一种雾气,遮蔽和吸收来自背景中类星体的明显的亮光模式。过去,哈勃对类星体的观测被用来绘制仙女座星系周围的日冕。通过分析来自28个类星体的紫外光模式,研究人员能够检测和描述大麦哲伦星系周围的物质,并确认日冕的存在。正如预测的那样,类星体光谱上印有碳、氧和硅元素的明显特征,这些特征构成了环绕银河系的热等离子体光晕。

十一 | 需要极其详细的紫外线光谱来探测日冕。"哈勃和FUSE的分辨率对这项研究至关重要,Krishnarao解释说。"日冕气体是如此的弥漫,它甚至几乎不存在。此外,它还与其他气体混合在一起,包括从麦哲伦云中拉出的气流和源自银河系的物质。"通过绘制结果,研究小组还发现,气体的数量随着与大麦哲伦云中心的距离而减少。

十二 | 这是一个完美的提示信号,表明这个日冕真的存在,它确实在为星系形成一个保护盾。如此稀薄的气体笼罩如何能够保护一个星系免遭破坏?任何试图进入星系的东西都必须先通过这种物质,所以它可以吸收一些冲击。此外,日冕是第一个可以被提取的材料。在放弃一点日冕的同时,受保护星系本身内部的气体,能够形成新的恒星。

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Published on:21:27:14


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