TY - JOUR
T1 - EMPRESS. III. Morphology, stellar population, and dynamics of extremely metal-poor galaxies (EMPGs)
T2 - Are EMPGs local analogs of high-z young galaxies?
AU - Isobe, Yuki
AU - Ouchi, Masami
AU - Kojima, Takashi
AU - Shibuya, Takatoshi
AU - Hayashi, Kohei
AU - Rauch, Michael
AU - Kikuchihara, Shotaro
AU - Zhang, Haibin
AU - Ono, Yoshiaki
AU - Fujimoto, Seiji
AU - Harikane, Yuichi
AU - Kim, Ji Hoon
AU - Komiyama, Yutaka
AU - Kusakabe, Haruka
AU - Lee, Chien Hsiu
AU - Mawatari, Ken
AU - Onodera, Masato
AU - Sugahara, Yuma
AU - Yabe, Kiyoto
N1 - Funding Information:
We thank Koki Kakiichi and Chengze Liu for having useful discussions. We are grateful to Daniel Prole for providing the coordinates of UDGs in Prole et al. (2019a). This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. We thank the staff of Las Campanas for their help with the observations. The Hyper Suprime-Cam (HSC) Collaboration includes the astronomical communities of Japan and Taiwan, and Princeton University. The HSC instrumentation and software were developed by the National Astronomical Observatory of Japan (NAOJ), the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), the University of Tokyo, the High Energy Accelerator Research Organization (KEK), the Academia Sinica Institute for Astronomy and Astrophysics in Taiwan (ASIAA), and Princeton University. Based on data collected at the Subaru Telescope and retrieved from the HSC data archive system, which is operated by Subaru Telescope and Astronomy Data Center at NAOJ. This work was supported by the joint research program of the Institute for Cosmic Ray Research (ICRR), University of Tokyo. The Cosmic Dawn Center is funded by the Danish National Research Foundation under grant No. 140. S.F. acknowledges support from the European Research Council (ERC) Consolidator Grant funding scheme (project ConTExt, grant No. 648179). This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 847523 “INTERACTIONS.” This work is supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan, as well as KAKENHI Grant-in-Aid for Scientific Research (A) (15H02064, 17H01110, and 17H01114) through Japan Society for the Promotion of Science (JSPS). Yuki Isobe, Takashi Kojima, Kohei Hayashi, Ken Mawatari, Masato Onodera, Yuma Sugahara, and Kiyoto Yabe are supported by JSPS KAKENHI grant Nos. 21J20785, 18J12840, 18J00277, 20K14516, 17K14257, 18J12727, and 18K13578, respectively.
Publisher Copyright:
© 2021. The American Astronomical Society. All rights reserved.
PY - 2021/9/10
Y1 - 2021/9/10
N2 - We present the morphology and stellar population of 27 extremely metal-poor galaxies (EMPGs) at z ∼ 0 with metallicities of 0.01–0.1 Ze. We conduct multicomponent surface brightness (SB) profile fitting for the deep Subaru/Hyper Suprime-Cam i-band images of the EMPGs with the GALFIT software, carefully removing the SB contributions of tails. We find that the EMPGs with a median stellar mass of log(M* M⊙) = 6.0 have a median Sérsic index of n = 1.1 and a median effective radius of re = 200 pc, suggesting that typical EMPGs have a very compact disk. We compare the EMPGs with z ∼ 6 galaxies and local galaxies on the size–mass (re–M*) diagram, and identify that the majority of the EMPGs have an re–M* relation similar to z ∼ 0 star-forming galaxies rather than z ∼ 6 galaxies. Not every EMPG is a local analog of high-z young galaxies in the re–M* relation. A spectrum of one pair of EMPG and tail, so far available, indicates that the tail is dynamically related to the EMPG with a median velocity difference of ΔV = 101 ± 32 km s-1. This moderately large ΔV cannot be explained by the dynamics of the tail, but likely by the infall on the tail. For the first time, we may identify the metal-poor star-forming system just now infalling into the tail.
AB - We present the morphology and stellar population of 27 extremely metal-poor galaxies (EMPGs) at z ∼ 0 with metallicities of 0.01–0.1 Ze. We conduct multicomponent surface brightness (SB) profile fitting for the deep Subaru/Hyper Suprime-Cam i-band images of the EMPGs with the GALFIT software, carefully removing the SB contributions of tails. We find that the EMPGs with a median stellar mass of log(M* M⊙) = 6.0 have a median Sérsic index of n = 1.1 and a median effective radius of re = 200 pc, suggesting that typical EMPGs have a very compact disk. We compare the EMPGs with z ∼ 6 galaxies and local galaxies on the size–mass (re–M*) diagram, and identify that the majority of the EMPGs have an re–M* relation similar to z ∼ 0 star-forming galaxies rather than z ∼ 6 galaxies. Not every EMPG is a local analog of high-z young galaxies in the re–M* relation. A spectrum of one pair of EMPG and tail, so far available, indicates that the tail is dynamically related to the EMPG with a median velocity difference of ΔV = 101 ± 32 km s-1. This moderately large ΔV cannot be explained by the dynamics of the tail, but likely by the infall on the tail. For the first time, we may identify the metal-poor star-forming system just now infalling into the tail.
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U2 - 10.3847/1538-4357/ac05bf
DO - 10.3847/1538-4357/ac05bf
M3 - Article
AN - SCOPUS:85115918370
SN - 0004-637X
VL - 918
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 54
ER -