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The Long-term Survival Chances of Young Massive Star Clusters

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 155-186页

作者： richard de grijs Geneviève Parmentier department of Physics & Astronomy The University of Sheffield Hicks Building Hounsfield Road Sheffield S3 7RH U. K.National Astronomical Observatories Chinese Academy of SciencesBeijing 100012 Institute of Astrophysics & Geophysics Université de LiègeAllée du 6 Aot17Sart-Tilman (B5c)B-4000 LiègeBelgium

We review the long-term survival chances of young massive star clusters （YMCs）, hallmarks of intense starburst episodes often associated with Violent galaxy interactions. We address the key question as to whether at least some of these YMCs can be considered protoglobular clusters （GCs）, in which case these would be expected to evolve into counterparts of the ubiquitous old GCs believed to be among the oldest galactic building blocks. In the absence of significant external perturbations, the key factor determining a cluster＇s long-term survival chances is the shape of its stellar initial mass function （IMF）. It is, however, not straightforward to assess the IMF shape in unresolved extragalactic YMCs. We discuss in detail the promise of using high-resolution spectroscopy to make progress towards this goal, as well as the numerous pitfalls associated with this approach. We also discuss the latest progress in worldwide efforts to better understand the evolution of entire cluster systems, the disruption processes they are affected by, and whether we can use recently gained insights to determine the nature of at least some of the YMCs observed in extragalactic starbursts as proto-GCs. We conclude that there is an increasing body of evidence that GC formation appears to be continuing until today; their long-term evolution crucially depends on their environmental conditions, however.

关键词： stellar dynamics - globular clusters general - galaxies interactions - Magellanic Clouds - galaxies starburst - galaxies star clusters

Stellar populations in star clusters

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Research in Astronomy and Astrophysics 2016年第12期16卷 1-18页

作者： Cheng-Yuan Li richard de grijs Li-Cai deng department of Physics and Astronomy Macquarie University Purple Mountain Observatory Chinese Academy of Sciences Kavli Institute for Astronomy & Astrophysics and department of Astronomy Peking University International Space Science Institute–Beijing Key Laboratory for Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences

Stellar populations contain the most important information about star cluster formation and evo- lution. Until several decades ago, star clusters were believed to be ideal laboratories for studies of simple stellar populations （SSPs）. However, discoveries of multiple stellar populations in Galactic globular clus- ters have expanded our view on stellar populations in star clusters. They have simultaneously generated a number of controversies, particularly as to whether young star clusters may have the same origin as old globular clusters. In addition, extensive studies have revealed that the SSP scenario does not seem to hold for some intermediate-age and young star clusters either, thus making the origin of multiple stellar popu- lations in star clusters even more complicated. Stellar population anomalies in numerous star clusters are well-documented, implying that the notion of star clusters as true SSPs faces serious challenges. In this review, we focus on stellar populations in massive clusters with different ages. We present the history and progress of research in this active field, as well as some of the most recent improvements, including ob- servational results and scenarios that have been proposed to explain the observations. Although our current ability to determine the origin of multiple stellar populations in star clusters is unsatisfactory, we propose a number of promising projects that may contribute to a significantly improved understanding of this subject.

关键词： galaxies: star clusters: general -- galaxies: star formation -- stars: rotation

Not-so-simple stellar populations in nearby resolved star clusters

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Not-so-simple stellar populations in nearby resolved star cl...

The International Astronomical Union’s East Asian Regional Office of Astronomy For development

中国天文学会2014年学术年会

作者： richard de grijs KIAA/PKU

＜正＞Until about a decade ago,star clusters were considered"simple"stellar populations:all stars in acluster were thought to have similar ages and the same *** the individual stellar masses were thought to vary,in essence conforming to a"universal"initial mass *** the past decade,this situation has changed ***,at the same time,star clusters are

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The International Astronomical Union’s East Asian Regional ...

Old stellar population synthesis:new age and mass estimates for Mayall II = G1

中国天文学会2015年学术年会

作者： richard de grijs 北京大学

＜正＞At the 2012 General Assembly of the International Astronomical Union（IAU）,the Office of Astronomy for development（OAD）programme announced a number of exciting new partnerships to assist with the IAU’s decadal strategic plan（2010-2020）.These landmark decisions included establishing a new coordinating centre that aims at using astronomy as a tool for development in East *** agreement covers two

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Research in Astronomy and Astrophysics 2009年第6期9卷 641-652页

作者： Jun Ma richard de grijs Zhou Fan Soo-Chang Rey Zhen-Yu Wu Xu Zhou Jiang-Hua Wu Zhao-Ji Jiang Jian-Sheng Chen Kyungsook Lee Sangmo Tony Sohn National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China department of Physics ＆ Astronomy The University of Sheffield Hicks Building Hounsfield Road Sheffield S3 7RH UK Graduate University Chinese Academy of Sciences Beijing 100049 China department of Astronomy and Space Science Chungnam National University Daejeon 305-764 Korea Center for Space Astrophysics Yonsei University Seoul 120-749 Korea California Institute of Technology MC 405-47 1200 E. California Boulevard Pasadena CA 91125

Mayall Ⅱ = G1 is one of the most luminous globular clusters （GCs） in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHKs 2MASS data, we construct the most extensive spectral energy distribution of G 1 to date, spanning the wavelength range from 1538 to 20 000A. A quantitative comparison with a variety of simple stellar population （SSP） models yields a mean age which is consistent with G1 being among the oldest building blocks of M31 and having formed within ～1.7 Gyr after the Big Bang. Irrespective of the SSP model or stellar initial mass function adopted, the resulting mass estimates （of order 10^7M⊙） indicate that GI is one of the most massive GCs in the Local Group. However, we speculate that the cluster＇s exceptionally high mass suggests that it may not be a genuine GC. Our results also suggest that G1 may contain, on average, （1.65±0.63） × 10^2L⊙ far-ultraviolet-bright, hot, extreme horizontal-branch stars, depending on the adopted SSP model. In addition, we demonstrate that extensive multi-passband photometry coupled with SSP analysis enables one to obtain age estimates for old SSPs that have similar accuracies as those from integrated spectroscopy or resolved stellar photometry, provided that some of the free parameters can be constrained independently.

关键词： galaxies individual (M31) -- galaxies star clusters -- galaxies stellar content

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十亿像素的相机，你会怎么用？

天文爱好者 2011年第12期 20-23页

作者：何锐思（richard de grijs）王琴（翻译）北京大学科维理天文和天体物理研究所华中师范大学

当我希望遇到一个好的摄影机会时，我喜欢用一个装有9百万像素CCD（光学传感器阵列，“电荷耦合器件”）的数码单反相机。虽然我几年前买入时，它还是最先进的设备，但是我最近已看到些广告，发现两千万像素的相机也都不算太贵了，所以... 详细信息

当我希望遇到一个好的摄影机会时，我喜欢用一个装有9百万像素CCD（光学传感器阵列，“电荷耦合器件”）的数码单反相机。虽然我几年前买入时，它还是最先进的设备，但是我最近已看到些广告，发现两千万像素的相机也都不算太贵了，所以说技术是在明显地向前发展。这些数字简单地说明这两种CCD分别包含了9百万和2千万像素。在一个可单独控制的二维数字光栅上，像素都是最小的单元。实际上，安置在我的单反相机中的CCD是由一个3696×2616像素的矩形光栅组成的。

关键词：十亿像素相机盖亚 CCD 卫星

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以星溯银河

天文爱好者 2019年第1期 25-31页

作者：何锐思(richard de grijs) 程思森(译) 麦考瑞大学物理与天文学系不详

近期,欧洲空间局“盖亚”卫星在揭开银河系形成史方面取得了重大突破。之前的研究显示,大型星系(如银河系)一般是由若干较小的星系融合的结果。于是,随之出现了一个新问题:像银河系这样的星系是许多小星系,还是少数稍大些的星系融合产生... 详细信息

近期,欧洲空间局“盖亚”卫星在揭开银河系形成史方面取得了重大突破。之前的研究显示,大型星系(如银河系)一般是由若干较小的星系融合的结果。于是,随之出现了一个新问题:像银河系这样的星系是许多小星系,还是少数稍大些的星系融合产生的?来自荷兰格罗宁根大学的阿米娜·海勒米(Amina Helmi)教授在其学术生涯中主要致力于寻找银河系中可能为我们提供其演化线索的“化石”。她利用银晕中恒星的化学组成、位置和轨道追溯它们的历史,并由此识别出塑造早期银河系的各个”融合者”的身份。

关键词：银河系欧洲空间局学术生涯化学组成星系演化线恒星银晕

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大气中的生命“密码”

天文爱好者 2019年第12期 15-22页

作者：何锐思程思淼(译) 麦考瑞大学物理与天文学系不详

近日,加拿大麦吉尔大学的两位天文学家采集到了地球的“指纹”,这将可用来鉴别能够支持生命的系外行星。伊芙琳·麦克唐纳(Evelyn Macdonald)和她的导师尼古拉斯·科文教授(Nicolas Cowan)利用科学卫星(SCISAT)十多年来观测地球大气的数... 详细信息

近日,加拿大麦吉尔大学的两位天文学家采集到了地球的“指纹”,这将可用来鉴别能够支持生命的系外行星。伊芙琳·麦克唐纳(Evelyn Macdonald)和她的导师尼古拉斯·科文教授(Nicolas Cowan)利用科学卫星(SCISAT)十多年来观测地球大气的数据,构建了地球的“凌星光谱”——地球大气在红外波段的指纹。

关键词：地球大气麦吉尔大学麦克唐纳系外行星红外波段指纹尼古拉斯 SAT

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盖亚“香肠”星系

天文爱好者 2019年第8期 20-25页

作者：何锐思程思淼(译) 麦考瑞大学物理与天文学系不详

在银河系的一生中,它极有可能跟许多星系发生过碰撞或其他形式的相互作用。事实上,这类相互作用在宇宙中十分常见.通过研究那些被吸积的物质留在银晕中的潮汐残留物,天文学家能够追溯银河系吸积物质的历史。对于十亿年前人马矮星系坠入... 详细信息

在银河系的一生中,它极有可能跟许多星系发生过碰撞或其他形式的相互作用。事实上,这类相互作用在宇宙中十分常见.通过研究那些被吸积的物质留在银晕中的潮汐残留物,天文学家能够追溯银河系吸积物质的历史。对于十亿年前人马矮星系坠入银心,如今在星系地图中留下了可见的潮汐星流这类最近发生的融合事件来说,这一方法尤其有效。

关键词：矮星系香肠相互作用银河系天文学家残留物潮汐物质