Outflows and AGN in the Nuclei of Merging Galaxies, Viewed with Laser Guide Star Adaptive Optics

用激光导星自适应光学器件观察合并星系核中的外流和活动星系核

• 批准号: 1412851
• 负责人: Claire Max
• 金额: $ 26.06万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-15 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1412851&HistoricalAwards=false
• 关键词: Outflows; AGN; Nuclei; Merging; Galaxies

Quasars are the most luminous objects in the universe. The active galactic nucleus (AGN) that is the quasar's powerhouse can outshine its entire host galaxy. In the more than fifty years since their discovery, a picture has emerged of a quasar as a supermassive black hole residing at or near the center of a large galaxy. Interstellar gas in the galaxy, perhaps the residue of stars disrupted by tidal forces as they orbit close to the black hole, falls into the black hole and in doing so is heated to very high temperatures and emits copious radiation over a wide range of wavelengths. Along with the gas inflow, it is also clear that quasars drive gas out of the nuclear region. An outstanding question in the evolution of galaxies is to what extent the outflow from a quasar expels the interstellar medium, thereby quenching star formation in the host galaxy. This effect could have a strong influence on the development of galaxies at early times in the universe. This project will use newly-developed imaging and spectroscopic techniques to study nearby active galaxies in fine detail to gain insights as to how and from where the outflow is driven. It will also study a sub-sample of active galaxies that may have double active nuclei at their centers. In addition, it will contribute to an established workforce development program on Maui and a teacher training program in California.Multiple lines of evidence suggest that quasars in the early universe drive massive galactic outflows that expel much of the interstellar medium in their host galaxies. These outflows are needed to quench star formation, limit black hole accretion, and give rise to observed relationships between the central black hole?s mass and properties of the galaxy's bulge. Without them, it is difficult to explain the old stellar population and low gas content of local "red and dead" massive galaxies, as well as their steeply declining number at high masses. For high-redshift galaxies it is difficult to study outflow processes in detail, because the galaxies have small apparent sizes and faint fluxes. This project will study the physical processes of nuclear outflows for nearby quasars and luminous infrared galaxies (0.01 z 0.15), using laser guide star adaptive optics coupled with integral field spectrographs which can map emission and absorption lines on scales of 10 - 100 pc in the host galaxy. The outflow characteristics thereby deduced from observations in the near-infrared will be compared to those at other wavelengths, including molecular observations by the Herschel satellite, ALMA, CARMA, and the SMA, and visible observations with integral field spectrographs such as Gemini's GMOS instrument. The project will also include observations of active galactic nuclei from the Sloan Digital Sky Survey with dual [O III] emission lines at 0.2 z 0.6 to identify outflows and distinguish them from dual active nuclei.

类星体是宇宙中最发光的天体。活跃星系核（AGN）是类星体的动力源，其光芒可以让整个宿主星系黯然失色。自发现以来的五十多年里，类星体的图像已经出现，它是一个位于大星系中心或附近的超大质量黑洞。星系中的星际气体，可能是恒星在靠近黑洞的轨道上被潮汐力破坏的残余物，落入黑洞，并在此过程中被加热到非常高的温度，并在很宽的波长范围内发出大量的辐射。随着气体的流入，类星体将气体驱赶出核区域也很明显。星系演化中的一个突出问题是类星体的流出在多大程度上驱逐了星际介质，从而抑制了宿主星系中的恒星形成。 这种效应可能对宇宙早期星系的发展产生强烈影响。 该项目将使用新开发的成像和光谱技术来详细研究附近的活动星系，以深入了解外流的驱动方式和来源。 它还将研究活动星系的子样本，这些星系的中心可能有双活动核。 此外，它将为毛伊岛既定的劳动力发展计划和加利福尼亚州的教师培训计划做出贡献。 多种证据表明，早期宇宙中的类星体驱动了大量的星系外流，驱逐了其宿主星系中的大部分星际介质。这些流出对于抑制恒星形成、限制黑洞吸积以及产生中心黑洞质量和星系核球特性之间的观察到的关系是必需的。 如果没有它们，就很难解释当地“红色和死亡”大质量星系的古老恒星数量和低气体含量，以及它们在大质量时数量的急剧下降。对于高红移星系，很难详细研究流出过程，因为星系的表观尺寸较小且通量微弱。该项目将利用激光导星自适应光学器件与积分场摄谱仪相结合，研究附近类星体和发光红外星系（0.01 z 0.15）核流出的物理过程，该摄谱仪可以在宿主星系中以 10 - 100 pc 的尺度绘制发射线和吸收线。由此从近红外观测中推导出的流出特征将与其他波长的流出特征进行比较，包括赫歇尔卫星、ALMA、CARMA和SMA的分子观测，以及使用积分场摄谱仪（例如Gemini的GMOS仪器）的可见观测。该项目还将包括斯隆数字巡天中使用 0.2 z 0.6 双 [O III] 发射线对活动星系核进行观测，以识别外流并将其与双活动核区分开来。