EMPRESS. XII. Statistics on the Dynamics and Gas Mass Fraction of Extremely-Metal Poor Galaxies
Yi Xu, Masami Ouchi, Yuki Isobe, Kimihiko Nakajima, Shinobu Ozaki, Nicolas F. Bouché, John H. Wise, Eric Emsellem, Haruka Kusakabe, Takashi Hattori, Tohru Nagao… 展开作者
Yi Xu, Masami Ouchi, Yuki Isobe, Kimihiko Nakajima, Shinobu Ozaki, Nicolas F. Bouché, John H. Wise, Eric Emsellem, Haruka Kusakabe, Takashi Hattori, Tohru Nagao, Gen Chiaki, Hajime Fukushima, Yuichi Harikane, Kohei Hayashi, Yutaka Hirai, Ji Hoon Kim, Michael V. Maseda, Kentaro Nagamine, Takatoshi Shibuya, Yuma Sugahara, Hidenobu Yajima, Shohei Aoyama, Seiji Fujimoto, Keita Fukushima, Shun Hatano, Akio K. Inoue, Tsuyoshi Ishigaki, Masahiro Kawasaki, Takashi Kojima, Yutaka Komiyama, Shuhei Koyama, Yusei Koyama, Chien-Hsiu Lee, Akinori Matsumoto, Ken Mawatari, Takashi J. Moriya, Kentaro Motohara, Kai Murai, Moka Nishigaki, Masato Onodera, Yoshiaki Ono, Michael Rauch, Tomoki Saito, Rin Sasaki, Akihiro Suzuki, Tsutomu T. Takeuchi, Hiroya Umeda, Masayuki Umemura, Kuria Watanabe, Kiyoto Yabe, Yechi Zhang
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18 pages, 9 figures, accepted for publication in ApJ
We present demography of the dynamics and gas-mass fraction of 33 extremely metal-poor galaxies (EMPGs) with metallicities of $0.015-0.195~Z_\odot$ and low stellar masses of $10^4-10^8~M_\odot$ in the local universe. We conduct deep optical integral-field spectroscopy (IFS) for the low-mass EMPGs with the medium high resolution ($R=7500$) grism of the 8m-Subaru FOCAS IFU instrument by the EMPRESS 3D survey, and investigate H$α$ emission of the EMPGs. Exploiting the resolution high enough for the low-mass galaxies, we derive gas dynamics with the H$α$ lines by the fitting of 3-dimensional disk models. We obtain an average maximum rotation velocity ($v_\mathrm{rot}$) of $15\pm3~\mathrm{km~s^{-1}}$ and an average intrinsic velocity dispersion ($σ_0$) of $27\pm10~\mathrm{km~s^{-1}}$ for 15 spatially resolved EMPGs out of the 33 EMPGs, and find that all of the 15 EMPGs have $v_\mathrm{rot}/σ_0<1$ suggesting dispersion dominated systems. There is a clear decreasing trend of $v_\mathrm{rot}/σ_0$ with the decreasing stellar mass and metallicity. We derive the gas mass fraction ($f_\mathrm{gas}$) for all of the 33 EMPGs, and find no clear dependence on stellar mass and metallicity. These $v_\mathrm{rot}/σ_0$ and $f_\mathrm{gas}$ trends should be compared with young high-$z$ galaxies observed by the forthcoming JWST IFS programs to understand the physical origins of the EMPGs in the local universe.
EMPRESS. XIII. Chemical Enrichments of Young Galaxies Near and Far at z ~ 0 and 4-10: Fe/O, Ar/O, S/O, and N/O Measurements with Chemical Evolution Model Comparisons
EMPRESS. IV. Extremely Metal-Poor Galaxies (EMPGs) Including Very Low-Mass Primordial Systems with M*=10^4--10^5 M_sun and 2--3% (O/H)_sun: High (Fe/O) Suggestive of Metal Enrichment by Hypernovae/Pair-Instability Supernovae
EMPRESS. II. Highly Fe-Enriched Metal-poor Galaxies with $\sim 1.0$ (Fe/O)$_\odot$ and $0.02$ (O/H)$_\odot$ : Possible Traces of Super Massive ($>300 M_{\odot}$) Stars in Early Galaxies
我们提出了当地年轻的低质量的元素丰度比和电离辐射（~$10^{6}$ M_sun）太阳氧丰度（O/H）_sun为2%的极端贫金属星系（EMPGs）（sSFR~300 Gyr $^{-1}$）和其他（极端）贫金属星系，这是由斯巴鲁调查（EMPRESS）和文献中探索的极贫金属代表汇编而成。在使用包括Keck和Subaru在内的8m级望远镜拍摄的EMPG的非常深的光谱中检测到了[FeIII] 4658和HeII 4686等弱发射线（Kojima et al. 2019，Izotov et al. 2018），使我们能够通过光电离模型推导出元素丰度比。结果表明，该星系的氮氧丰度比（N/O）低于20%（N/O）太阳，与氧丰度低的特点相一致。然而，铁氧丰度比（Fe/O）的EMPGs一般都很高;与2%的太阳氧丰度的EMPGs显示高Fe/O比~90 - 140%（Fe/O）_sun，这是不可能解释的建议方案的Ia型超新星铁生产，铁的尘埃耗尽，和贫金属气体流入先前富含金属的星系与太阳丰度。此外，这些EMPG有非常高的HeII 4686/H $β$比~1/40，这是现有的模型中没有重现的高质量X射线双星的祖先恒星质量小于120 M_sun。比较恒星核合成和光电离模型与EMPG的全面样本，确定本和以前的EMPG研究，我们提出，高Fe/O比和高HeII 4686/H $β$比解释过去存在的超大质量（$>$…
EMPRESS. III. Morphology, Stellar Population, and Dynamics of Extremely Metal Poor Galaxies (EMPGs): Are EMPGs Local Analogs of High-$z$ Young Galaxies?
Extremely Metal-Poor Representatives Explored by the Subaru Survey (EMPRESS). I. A Successful Machine Learning Selection of Metal-Poor Galaxies and the Discovery of a Galaxy with M*<10^6 M_sun and 0.016 Z_sun
EMPRESS. X. Spatially resolved mass-metallicity relation in extremely metal-poor galaxies: evidence of episodic star-formation fueled by a metal-poor gas infall
EMPRESS. IX. Extremely Metal-Poor Galaxies are Very Gas-Rich Dispersion-Dominated Systems: Will JWST Witness Gaseous Turbulent High-z Primordial Galaxies?
EMPRESS. VIII. A New Determination of Primordial He Abundance with Extremely Metal-Poor Galaxies: A Suggestion of the Lepton Asymmetry and Implications for the Hubble Tension
Population Studies. XIII. A New Analysis of the Bidelman-MacConnell "Weak-Metal" Stars - Confirmation of Metal-Poor Stars in the Thick Disk of the Galaxy
EMPRESS. XV. A New Determination of the Primordial Helium Abundance Suggesting a Moderately Low $Y_\mathrm{P}$ Value
Institute for Cosmic Ray Research, The University of Tokyo（东京大学宇宙射线研究所）；Department of Physics, Graduate School of Science, The University of Tokyo（东京大学理学研究科物理学系）；National Astronomical Observatory of Japan, National Institutes of Natural Sciences（日本国立天文台，国立自然科学研究院）；Department of Astronomical Science, SOKENDAI (The Graduate University for Advanced Studies)（SOKENDAI（ advanced studies研究生院）天体科学系）；Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo（东京大学 Kavli宇宙物理数学研究所 (WPI)）；Department of Physics, Tohoku University（东北大学物理学系）
GHASP: an H$α$ kinematics survey of spiral galaxies - XII. Distribution of luminous and dark matter in spiral and irregular nearby galaxies using R$_c$-band photometry
A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE).XIII. The role of ram-pressure stripping in transforming the diffuse and ultra-diffuse galaxies in the Virgo cluster
