CAREER: Structure Formation and Support by Magnetized, Supersonic Turbulence in the Interstellar Medium and Star-Forming Regions

Mordecai-Mark Mac Low博士被任命为美国自然历史博物馆天体物理学助理馆长，这为利用最先进的天文馆的资产进行公共教育和对恒星诞生和星际气体结构的基础研究提供了一个非凡的机会。恒星是由巨大的星际气体云形成的，这些气体云在自身引力的作用下坍缩。在我们自己的星系和其他星系中观察到的气体，如果没有某种支持，在星系生命周期的一小部分时间内，都会坍缩成恒星。在星际气体中观察到超音速随机运动（湍流），在气体中观察到密度更大的恒星形成云。这些超声速运动似乎支持云不立即坍缩，然而这些超声速运动产生的冲击波将气体扫向极其密集的片状和细丝。在星际气体中，这些密集的区域可能是恒星形成云的祖先，而在云中，这些区域似乎演变成更密集的核心，在那里可以观察到最年轻的恒星。了解由超音速运动引起的支撑和崩塌之间的平衡是如何工作的，将为理解恒星形成星系的演化和恒星的起源开辟道路，包括我们自己的太阳。Mac Low正在计算磁化气体中超音速湍流的三维模型，以研究恒星形成的云是如何被星际气体卷走的，以及原恒星的核心是如何依次被卷走的。他包括了对超新星爆炸和驱动气体中超音速运动的原恒星流出的真实描述，以及气体的加热和冷却。他还模拟了电离辐射是如何通过模拟的密度结构转移的，以了解我们自己和其他星系中的气体是如何在离热恒星很远的地方电离的，以及分子云是如何发射和辐射冷却的。博物馆的玫瑰地球和空间科学中心包括两个永久性展厅——宇宙厅和行星地球厅——以及一个新的海登天文馆。新的天文馆有一个蔡司星投影仪，结合了模拟投影技术的最新发展，和一个数字圆顶，可以实时投影900万像素的计算机生成的图形。麦克·洛博士将他的研究成果，以及他对现代天体物理学的一般知识，融入到为天文馆制作的太空节目中，融入到天文馆和宇宙厅的其他展品中，以及它们的相关网站中。他还与大学预科教师合作，将现代研究的精神和成果融入他们的教学中。该项目由天文科学学部资助

AST-9985392MAC LOWThe appointment of Dr. Mordecai-Mark Mac Low to a position as Assistant Curator of Astrophysics at the American Museum of Natural History presents an extraordinary opportunity to combine public education using the assets of a state-of-the-art planetarium with fundamental research on the birth of stars and the structure of the interstellar gas. Stars are formed from huge clouds of interstellar gas that collapse under the force of their own gravity. The gas observed in our own and other galaxies would all collapse into stars in a small fraction of the lifetimes of the galaxies if it were not somehow supported. Supersonic random motions (turbulence) are observed in the interstellar gas, and in the denser star-forming clouds observed in that gas. These supersonic motions appear to support the clouds against immediate collapse, yet shock waves from these supersonic motions sweep gas up into extremely dense sheets and filaments. In the interstellar gas, these dense regions may be the progenitors of the star-forming clouds, while within the clouds, these regions appear to evolve into the even denser cores in which the very youngest stars are observed. Understanding how the balance between support and collapse caused by the supersonic motion works will open the way to understanding the evolution of star-forming galaxies and the origins of stars including our own SunDr. Mac Low is computing three-dimensional models of supersonic turbulence in magnetized gas in order to study how star-forming clouds are swept up in the interstellar gas and how protostellar cores are in turn swept up in the clouds. He includes realistic descriptions of the supernova explosions and protostellar outflows that drive the supersonic motions in the gas, as well as the heating and cooling of the gas. He also models how ionizing radiation is transferred through the modeled density structure to understand how the gas in our own and other galaxy is ionized at enormous distances from hot stars, as well as how molecular clouds emit and are radiatively cooled. The Rose Center for Earth and Space Sciences at the Museum includes two permanent exhibition halls---the Hall of the Universe and the Hall of Planet Earth---and a new Hayden Planetarium. The new Planetarium has both a Zeiss star projector incorporating the latest developments in analog projection technology, and a Digital Dome that allows the projection of nine megapixels of computer-generated graphics in real time. Dr. Mac Low incorporates the results of his research, as well as his general knowledge of modern astrophysics, into the Space Shows produced for the Planetarium, into other exhibits in the Planetarium and the Hall of the Universe, and into their associated web sites. He also works with pre-college teachers to incorporate the spirit and results of modern research into their teaching.This project is supported by funds from the Division of Astronomical Sciences.***