The Imprint of Galaxy Formation on the Intergalactic Environment

星系形成对星系际环境的影响

• 批准号: 0908910
• 负责人: Piero Madau
• 金额: $ 55.15万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0908910&HistoricalAwards=false
• 关键词: Imprint; Galaxy; Formation; Intergalactic; Environment

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Dr. Madau and his team will combine observations of the gas from which the galaxies were formed with theoretical and numerical studies of the state of that gas. The intergalactic gas is ionized by the ultraviolet light from short-lived massive stars and from the active nuclei of galaxies, so the amount of neutral gas tells us about past star formation, and about the black holes that lie at the centers of galaxies and power their active nuclei. To set limits on this ionizing light at times when the cosmos had expanded only to a quarter of its present size, the team will examine the spectra of quasars dating from this period, and make a census of the deep absorption lines of neutral hydrogen in their light. They will take infrared spectra of even more distant quasars to measure the absorption lines of heavier elements that are produced in stellar interiors, to examine how rapidly these were produced from stars and flung into the intergalactic gas. By looking at spectra of pairs of quasars that are nearby on the sky, the team will study gas around the nearer quasar by its absorption of the light of the more distant object. The team will improve CUBA, a one-dimensional radiative transfer code, and release it to the public. This code will be used to trace ionizing photons as they propagate through models of the cosmos that follow both the invisible dark matter and the gas, as gas condenses into star-forming galaxies. These calculations will also consider the effect of galactic winds in blowing the metals formed in the stars out into the intergalactic gas. A graduate student and a postdoc will be trained by participating in the research. Team members expect to mentor undergraduate researchers, and to take part in a summer program for talented undergraduates from low-income families. The upgraded CUBA code will be released to the astronomical community, and visualizations from the simulation runs will be available for public outreach.

该奖项是根据2009年《美国回收与再投资法》（公共法第111-5）.DR资助的。 Madau和他的团队将结合对星系的天然气的观察结果，并与该气体状态的理论和数值研究相结合。 层间气体通过来自短寿命的大恒星和星系的活跃核的紫外线被电离，因此中性气的量告诉我们过去的恒星形成，以及有关星系中心的黑洞和动力核的黑洞。 为了在宇宙仅扩展到其当前大小的四分之一时对这种电离光的限制，该团队将检查从这一段时期来看的类星体的光谱，并在其光中对中性氢的深度吸收线进行普查。 他们将采用更遥远的类星体的红外光谱，以测量在恒星内部产生的较重元素的吸收系，以检查这些元素从恒星中产生的速度并参阅粉间气体的速度。 通过查看附近天空附近的一对类星体的光谱，该团队将通过吸收更遥远的物体的光来研究较近的类星体周围的气体。 该团队将改善古巴，这是一维辐射转移代码，并将其发布给公众。 该代码将用于跟踪电离光子通过遵循无形的暗物质和气体的宇宙模型传播时，因为气体将气体凝结成星形的星系。 这些计算还将考虑银河风在将恒星中形成的金属吹入呈白层间气体中的影响。 研究生和博士后将通过参与研究培训。 团队成员期望指导本科研究人员，并为低收入家庭的才华横溢的本科生参加夏季计划。 升级的古巴代码将发布给天文学界，模拟运行中的可视化将用于公共宣传。