Binaries are very common in galaxies, and more than half of Galactic hot subdwarf stars, which are thought as a possible origin of UV-upturn of old stellar populations, are found in binaries. Previous works showed that binary evolution can make the spectra of binary star populations significantly different from those of single star populations. However, the effect of binary evolution has not been taken into account in most works of spectral fitting of galaxies. This paper studies the role of binary evolution in spectral fitting of early-type galaxies, via a stellar population synthesis model including both single and binary star populations. Spectra from ultraviolet to optical band are fitted to determine a few parameters of galaxies. The results show that the inclusion of binaries in stellar population models may lead to obvious change in the determination of some galaxy parameters and therefore it is potentially important for spectral studies. In particular, the ages of young components of composite stellar populations become much older when using binary star population models instead of single star population models. This implies that binary star population models will measure significantly different star formation histories (SFHs) for galaxies compared to single star population models. In addition, stellar population models with binary interactions measure larger dust extinctions than single star population models on average. It suggests that when using binary star population models instead of single star population models, negative extinctions are possibly unnecessary in spectral fitting of early-type galaxies.
The Evolution of the Fractions of Quiescent and Star-forming Galaxies as a Function of Stellar Mass Since z=3: Increasing Importance of Massive, Dusty Star-forming Galaxies in the Early Universe
利用UltraVISTA DR 1和3D-HST星表,我们构建了一个恒星质量完整的样本,其独特的组合调查的体积和深度,研究的分数的演化的静止星系,适度清晰的恒星形成的星系,尘埃恒星形成的星系作为一个函数的恒星质量在红移间隔$0.2 \le z \le 3.0$。我们发现,尘埃恒星形成星系的整体星系人口中的作用变得更加重要,随着恒星质量的增加,并迅速增长的红移。具体来说,尘埃恒星形成星系占主导地位的星系人口与$\log{(M_{\rm star}/M_{\odot})} \gtrsim 10.3$在$z\gtrsim2$。尘埃和非尘埃恒星形成星系的比例作为恒星质量的函数,随红移的变化很小。尘埃恒星形成星系在$\log{(M_{\rm star}/M_{\odot})} \gtrsim 10.0-10.5$的恒星形成种群中占主导地位,是$\sim$ 3-5的一个因子,而在$\log{(M_{\rm star}/M_{\odot})} \lesssim 10$中,清晰的恒星形成星系占主导地位。在$\log{(M_{\rm star}/M_{\odot})} > 10.5$,红色星系在所有红移$z<3$的星系群中占主导地位,这可能是因为它们处于静止状态(在晚期)或尘埃恒星形成(在早期宇宙)。
Uncertainties in high-$z$ galaxy properties inferred from SED fitting using JWST NIRCam photometry
Yonsei University(延世大学);University of Chicago(芝加哥大学);Kavli Institute for Cosmological Physics, University of Chicago(芝加哥大学卡弗里宇宙物理研究所);Centre de Recherche Astrophysique de Lyon UMR5574, Univ Lyon, Univ Lyon1, Ens de Lyon(里昂天体物理研究中心)
Early type galaxies and structural parameters from ESO public survey KiDS
Kilo Degree Survey(KiDS)是利用VLT巡天望远镜(VST)进行的大规模光学成像巡天,VST是研究星系演化的理想工具。我们期望观测到数以百万计的星系,我们提取的四个波段(u,g,r和i)的结构参数。该样本将代表最大的数据集,其测量的结构参数高达红移$z=0.5$。在本文中,我们将介绍样本,并描述使用2DPHOT环境的2D拟合过程和使用外部目录验证参数。
CSST Preparations: Galaxy Completeness and Sérsic Profile Fitting across the Wide, Deep, and Extreme Fields
Xiamen University(厦门大学);Peking University(北京大学);Kavli Institute for Astronomy and Astrophysics, Peking University(北京大学科维理天文与天体物理研究所);Shanghai Jiao Tong University(上海交通大学)
Quantifying Element Importance for Mass Recovery from Population III Supernova Yield Fits
University of Chicago(芝加哥大学);Kavli Institute for Cosmological Physics, University of Chicago(芝加哥大学卡弗里宇宙物理学研究所);NSF-Simons AI Institute for the Sky (SkAI)(美国国家科学基金会-西蒙斯天空人工智能研究所);NSF NOIRLab(美国国家科学基金会NOIR天文台);Oregon State University(俄勒冈州立大学)
The JWST Resolved Stellar Populations Early Release Science Program. IX. The RR Lyrae Population in WLM with HST and JWST
Minnesota Institute for Astrophysics, University of Minnesota(明尼苏达大学天体物理研究所);Department of Astronomy, University of California, Berkeley(加州大学伯克利分校天文学系);Space Telescope Science Institute(太空望远镜科学研究所);Department of Physics and Astronomy, Rutgers, the State University of New Jersey(新泽西州立大学罗格斯大学物理与天文系)
Early Planet Formation in Embedded Disks (eDisk). VIII. A Small Protostellar Disk around the Extremely Low-Mass and Young Class 0 Protostar, IRAS 15398-3359