Red Geyser Galaxies and the Suppression of Star Formation

红色间歇泉星系和恒星形成的抑制

• 批准号: 1816388
• 负责人: Kevin Bundy
• 金额: $ 27.85万
• 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: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1816388&HistoricalAwards=false
• 关键词: Red; Geyser; Galaxies; Suppression; Star

For most of cosmic time, typical galaxies grow continuously by turning hydrogen and helium gas into new stars. However, in the last few billion years (roughly the most recent 25% of cosmic history), many galaxies stopped forming stars and seem to have entered a permanent state of quiescence. Our own Milky Way galaxy may be undergoing a similar fate. Astronomers are not only trying to understand what initially stops star formation in these galaxies, but what keeps it from re-starting when fresh supplies of gas become available. This project seeks to understand a newly-discovered phenomenon that may play a role. So-called "red geyser" galaxies host super-massive black holes at their centers that periodically emanate a wind of hot gas that spreads through the entire galaxy. This hot gas may be able to heat up cooler reservoirs and prevent them from collapsing into new stars. This project will confirm the relationship between red geysers and central black holes and study red geyser winds in detail to understand how they impact their host galaxies. This program will also contribute to training in research methods for students. It will support the use of specialized Jupyter-type Marvin notebooks for astronomical research through training classes for high school students and early undergraduates. This training will provide experience and job-skills for next generation researchers.These investigators have recently discovered a new class of quiescent, relatively common early- type galaxy that hosts large-scale, AGN-driven winds. These "red geysers''---found in 5-10% of the quiescent population---may be the missing energy source needed to maintain low levels of star formation in galaxies where star formation in general ceased long ago. Initial integral field observations from the relatively low resolution (R~2000; 2.5 arcsec FWHM) MaNGA Survey revealed characteristic ionized gas velocity fields. This project addresses two key issues through follow-up observations with the Keck Observatory. Investigators seek to determine (1) whether the tell-tale enhanced emission is due to shocks or gas over-densities, and (2) how the wind energy couples to the cooler ambient gas in order to suppress star formation. Both questions will be addressed by analyzing recently obtained Keck spectroscopic data that spatially and spectrally resolves the multicomponent gas structure with finer detail, allowing the investigators to search for shocks and turbulence at the interface between the wind and cooler material. These Keck observations, obtained for six red geysers over two nights, will also constrain a quantitative wind model to confirm the role of red geysers in suppressing late-time star formation. Finally, they will test the hypothesis that these winds are driven by low-luminosity AGN feedback by stacking the available but shallow radio flux observations to determine whether radio AGN activity is more often associated with optical identification of the red geyser phenomenon.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.

在宇宙的大部分时间里，典型的星系通过将氢气和氦气转化为新的恒星而不断增长。然而，在过去的几十亿年里（大约是最近宇宙历史的25%），许多星系停止了恒星的形成，似乎进入了一种永久的静止状态。我们的银河系可能正经历着类似的命运。天文学家不仅试图了解这些星系中最初阻止恒星形成的原因，而且还试图了解当新的气体供应可用时，是什么阻止了恒星的形成。这个项目试图理解一个可能起作用的新发现的现象。所谓的“红色间歇泉”星系的中心有超大质量的黑洞，这些黑洞周期性地散发出一股热气风，蔓延到整个星系。这种热气体可能会加热较冷的储层，防止它们坍缩成新的恒星。该项目将确认红色间歇泉和中心黑洞之间的关系，并详细研究红色间歇泉风，以了解它们如何影响宿主星系。该项目还将有助于培养学生的研究方法。它将通过对高中生和早期本科生的培训课程，支持使用专门的木星式马文笔记本进行天文研究。这次培训将为下一代研究人员提供经验和工作技能。这些研究人员最近发现了一类新的静止的、相对常见的早期星系，它们拥有大规模的、由agn驱动的风。这些“红色间歇泉”——在静止人口的5-10%中发现——可能是在恒星形成通常很久以前就停止的星系中维持低水平恒星形成所需的缺失能量来源。相对低分辨率（R~2000； 2.5弧秒FWHM） MaNGA巡天的初始积分现场观测显示了特征性的电离气体速度场。该项目通过与凯克天文台的后续观测解决了两个关键问题。研究人员试图确定(1)这种明显的增强发射是由于冲击还是气体密度过大，以及(2)风能如何与较冷的环境气体耦合以抑制恒星形成。这两个问题都将通过分析最近获得的Keck光谱数据来解决，该数据在空间和光谱上更详细地解决了多组分气体结构，使研究人员能够在风和较冷物质之间的界面上搜索冲击和湍流。这些凯克在两个晚上对六个红色间歇泉的观测结果，也将限制定量风模型，以确认红色间歇泉在抑制晚期恒星形成中的作用。最后，他们将测试这些风是由低亮度AGN反馈驱动的假设，通过叠加可用的但较浅的射电通量观测来确定射电AGN活动是否更经常与红色间歇泉现象的光学识别联系在一起。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。

项目成果

Radio Morphology of Red Geysers

• DOI: 10.3847/1538-4357/ac24a0
• 发表时间: 2021-09
• 期刊: The Astrophysical Journal
• 作者: N. Roy;E. Moravec;K. Bundy;M. Hardcastle;G. Gürkan;Ranieri Diego Baldi;S. Leslie;K. Masters;J. Gelfand;R. Riffel;R. Riffel;Beatriz Mingo Fernandez;A. Drabent

Detecting Radio AGN Signatures in Red Geysers

• DOI: 10.3847/1538-4357/aaee72
• 发表时间: 2018-11
• 期刊: The Astrophysical Journal
• 作者: N. Roy;K. Bundy;Edmond Cheung;W. Rujopakarn;M. Cappellari;F. Belfiore;R. Yan;T. Heckman;M. Bershady;J. Greene;K. Westfall;N. Drory;K. Rubin;D. Law;Kai Zhang;J. Gelfand;D. Bizyaev;D. Wake;K. Masters;D. Thomas;Cheng Li;R. Riffel

Evidence of Wind Signatures in the Gas Velocity Profiles of Red Geysers

• DOI: 10.3847/1538-4357/abf1e6
• 发表时间: 2021-03
• 期刊: The Astrophysical Journal
• 作者: N. Roy;K. Bundy;R. Nevin;F. Belfiore;R. Yan;S. Campbell;R. Riffel;R. Riffel;M. Bershady;K. Westfall;N. Drory;Kai Zhang

Signatures of Inflowing Gas in Red Geyser Galaxies Hosting Radio Active Galactic Nuclei

• DOI: 10.3847/1538-4357/ac0f74
• 发表时间: 2021-06
• 期刊: The Astrophysical Journal
• 作者: N. Roy;K. Bundy;K. Rubin;K. Rowlands;K. Westfall;R. Riffel;D. Bizyaev;D. Stark;R. Riffel;I. Lacerna;P. Nair;Xuanyi Wu;N. Drory