A Systematic Search for Detached Tidal Dwarf Galaxies

系统搜索分离的潮汐矮星系

• 批准号: 1714491
• 负责人: Beverly Smith
• 金额: $ 3.83万
• 依托单位: East Tennessee State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1714491&HistoricalAwards=false
• 关键词: Systematic; Search; Detached; Tidal; Dwarf

Our home galaxy, the Milky Way, is one of billions of galaxies in the Universe. It is a flattened disk of stars. The Milky Way is on a collision course with a similar disk galaxy, the Andromeda galaxy. Such gravitational interactions between galaxies change the structure of the galaxies. Tidal forces during the collision produce long streamers of stars that extend hundreds of thousands of light years into space. These are called tidal tails. Concentrations of stars in these tails resemble the small dwarf galaxies observed near the Milky Way. Some tidal dwarf galaxies may separate from their parent galaxies to become independent dwarf galaxies. Alternatively, tidal dwarfs may disperse with time with their stars being spread throughout intergalactic space. A third possibility is that these tidal dwarfs may fall back into their parent galaxy. The number of tidal dwarfs that detach from their original galaxies is not yet known. The investigator seeks to understand the remnants of these galaxies created during interactions and test whether observations of these dwarf galaxies be used to understand the history of galaxy formation. The investigator will employ undergraduate students as research assistants. These students will be trained in data analysis, problem solving, and scientific techniques. They will be encouraged to present their results at local and regional conferences. This experience will better prepare the students for careers as scientists, teachers, or data analysts.The investigator will compare the tidal dwarf galaxies near nearby interacting galaxies and a control sample of isolated disk galaxies. Ultraviolet, visible light, and infrared images will be searched for possible tidal dwarfs near these galaxies. The properties of these objects will be compared to those of other dwarf galaxies. The results will be compared to computer simulations of tidal dwarf formation and evolution. The final list of tidal dwarf galaxies will be made available to the public. The results of this project will test theories of galaxy formation. Galaxy interactions were more common when the Universe was younger. Tidal dwarf galaxies cannot be easily studied in more distant galaxies. However, they can be easily studied in nearby interacting galaxies. The investigator will use archival data from the infrared (IR), ultraviolet (UV) and optical telescopes, including the Sloan Digitized Sky Survey. The interacting galaxy sample includes 46 nearby pairs of galaxies with tidal tails. The control sample is a set of 39 normal spiral galaxies. The images around the targeted galaxies will be searched for possible tidal dwarf galaxies. The UV/optical/IR data will be compared to models of aging stellar populations to determine the average age of the stars in these regions and the total mass of the stars. The galaxies in the sample have a median distance of only 44 megaparsecs; thus, the survey will be sensitive to regions with star formation rates of 0.001 solar masses per year and stellar masses of 100,000 solar masses. The numbers of possible tidal dwarfs around the interacting galaxies will be compared with those near the normal spirals to determine whether there is an excess near interacting galaxies.

我们的家园银河系是宇宙中数十亿个星系中的一个。它是由恒星组成的扁平圆盘。银河系正在与一个类似的盘状星系仙女座星系发生碰撞。星系之间的这种引力相互作用改变了星系的结构。碰撞过程中的潮汐力产生了长长的恒星流带，向太空延伸数十万光年。这些被称为潮尾。在这些彗尾中聚集的恒星类似于在银河系附近观测到的小矮星系。一些潮汐矮星系可能会从它们的母星系中分离出来，成为独立的矮星系。另外，潮汐矮星可能随着时间的推移而分散，它们的恒星散布在星系间的空间中。第三种可能性是，这些潮汐矮星可能会落回它们的母星系。从原来的星系中分离出来的潮汐矮星的数量尚不清楚。研究者试图了解在相互作用中产生的这些星系的残余物，并测试对这些矮星系的观察是否可以用来了解星系形成的历史。研究者将聘请本科生作为研究助理。这些学生将接受数据分析、问题解决和科学技术方面的培训。将鼓励他们在地方和区域会议上介绍他们的成果。这种经历将更好地为学生成为科学家、教师或数据分析师做好准备。研究人员将比较邻近相互作用星系附近的潮汐矮星系和孤立盘状星系的对照样本。紫外线、可见光和红外图像将在这些星系附近搜索可能的潮汐矮星。这些天体的特性将与其他矮星系的特性进行比较。结果将与潮汐矮星形成和演化的计算机模拟进行比较。潮汐矮星系的最终名单将向公众公布。这个项目的结果将检验星系形成的理论。在宇宙较年轻的时候，星系间的相互作用更为常见。潮汐矮星系在更遥远的星系中不容易被研究。然而，它们可以很容易地在附近相互作用的星系中进行研究。研究人员将使用来自红外（IR）、紫外线（UV）和光学望远镜的档案数据，包括斯隆数字化巡天。相互作用的星系样本包括46对附近有潮汐尾的星系。对照样本是一组39个正常的螺旋星系。目标星系周围的图像将被搜索以寻找可能的潮汐矮星系。紫外/光学/红外数据将与老化恒星群的模型进行比较，以确定这些区域恒星的平均年龄和恒星的总质量。样本中星系的中间距离只有44百万秒差距；因此，该调查将对恒星形成速度为每年0.001太阳质量和恒星质量为100,000太阳质量的区域敏感。相互作用星系周围可能的潮汐矮星数量将与正常螺旋附近的潮汐矮星数量进行比较，以确定相互作用星系附近是否有多余的潮汐矮星。

项目成果

The Hot Gas Exhaust of Starburst Engines in Mergers: Testing Models of Stellar Feedback and Star Formation Regulation

合并中星爆发动机的热气排放：恒星反馈和恒星形成调节的测试模型

• DOI: 10.3847/1538-3881/ab3e72
• 发表时间: 2019
• 期刊: The Astronomical Journal
• 作者: Smith, Beverly J.;Wagstaff, Peter;Struck, Curtis;Soria, Roberto;Dunn, Brianne;Swartz, Douglas;Giroux, Mark L.
• 通讯作者: Giroux, Mark L.