Direct Comparisons of Black Hole Mass Measurements

黑洞经常出现在科幻小说中，但现在它们也是科学事实。这些看不见的物体是宇宙中最极端的。生活在星系中心的黑洞包含的物质相当于数百万或数十亿个太阳，但它们被压缩成令人难以置信的小尺寸。这意味着它们有巨大的引力。黑洞是不可见的，因为它们不发出任何光，但它们可以通过对周围物体的影响来探测到。就像风是看不见的，但它能明显地摇动树叶一样，黑洞是看不见的，但它的引力在恒星和发光的气体周围旋转。天文学家已经开发了几种不同的方法来使用望远镜来测量不可见黑洞周围恒星和气体的运动。更快的运动表明黑洞的引力更大。引力更大的黑洞包含更多坍塌的物质，因此恒星和气体的可见运动使天文学家能够“称重”不可见的黑洞。研究人员收集了一个小样本，他们可以用两种最广泛使用的方法对所有黑洞进行称重。在更广泛的影响方面，PI将与大亚特兰大的女童子军合作，为4-5年级和高中的女孩开发和提供天文学讲习班。PI将通过她持续的承诺，促进和参与各种各样的公共外展活动，使更广泛的社区参与进来，目标是将科学素养和科学鉴赏带给广大受众。黑洞是宇宙中最极端的物体之一。在星系中心发现的黑洞拥有数百万或数十亿个太阳的质量，但它们被坍缩成无限小的大小。虽然黑洞不发光，所以看不见，但它们对附近恒星或气体的引力作用可以探测到。因此，天文学家开发了几种不同的技术来测量恒星和气体的运动，以限制黑洞的质量。但是很难比较不同的技术在多大程度上彼此一致，因为每一种技术都需要一组特定的条件。然而，这是一个需要检查的重要问题，因为研究近距离黑洞的方法大多是一种，而研究遥远黑洞的方法则完全不同。遥远的天体被看作是它们过去的样子，所以附近和遥远的黑洞的大量样本被用来了解它们是如何随着时间的推移而诞生和成长的。因此，重要的是要确保这两种技术被校准到相同的质量尺度。研究人员已经收集了一小部分黑洞，在那里他们可以使用两种最广泛使用的方法来确定它们的质量。在这个程序中，他们将应用这两种方法，并仔细比较他们的结果。这将使他们第一次确定这两种技术是否给出了相似的答案，或者是否存在以前未知的偏见影响我们对黑洞及其星系的理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Black holes often appear in science fiction, but they are now also science fact. These invisible objects are some of the most extreme in the universe. The black holes that live in the centers of galaxies contain as much material as millions or billions of Suns, but they are collapsed down into incredibly small sizes. This means that they have enormous amounts of gravity. While black holes are invisible because they do not give off any light, they can be detected by their effects on objects around them. Just as the wind is invisible but it clearly shakes leaves, black holes are invisible but their gravity whips around stars and glowing gas. Astronomers have developed a few different ways to use telescopes to measure the motions of stars and gas around invisible black holes. Faster motions indicate more gravity from a black hole. Black holes with more gravity contain more material that has collapsed down, and so the visible motions of stars and gas allow astronomers to “weigh” invisible black holes. The researchers have collected a small sample where they can weigh all of the black holes with both of the most widely-used methods. In Broader Impacts, the PI will work with the Girl Scouts of Greater Atlanta to develop and offer astronomy workshops that target girls in grades 4-5 and high school. The PI will engage the broader community through her ongoing commitments to facilitate and participate in a wide variety of public outreach events, with the goal of bringing science literacy and appreciation to a broad audience.Black holes are some of the most extreme objects in the universe. The black holes that are found in the centers of galaxies contain the mass of millions or billions of Suns, but they are collapsed down into infinitesimal sizes. While black holes are invisible because they do not emit any light, they can be detected by their gravitational effects on nearby stars or gas. Astronomers have thus developed a few different techniques to measure the motions of stars and gas to constrain black hole masses. But it is difficult to compare how well the different techniques agree with each other because each one requires a specific set of conditions. Nevertheless, this is an important point to check, because nearby black holes are mostly studied with one method but a completely different method is used for distant black holes. Distant celestial objects are seen as they were in the past, so large samples of nearby and distant black holes are used to understand how they were born and grow over time. Thus it is important to be sure that both techniques are calibrated to the same mass scale. The researchers have collected a small number of black holes where they can determine their masses using both of the most widely-used methods. In this program, they will apply both methods and carefully compare their results. This will allow them to determine for the first time if both techniques are giving similar answers, or if there may be previously unknown biases affecting our understanding of black holes and their galaxies.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.