EMPRESS. III. Morphology, Stellar Population, and Dynamics of Extremely Metal-poor Galaxies (EMPGs): Are EMPGs Local Analogs of High-z Young Galaxies?

Research output: Contribution to journalJournal articleResearchpeer-review

  • Yuki Isobe
  • Masami Ouchi
  • Takashi Kojima
  • Takatoshi Shibuya
  • Kohei Hayashi
  • Michael Rauch
  • Shotaro Kikuchihara
  • Haibin Zhang
  • Yoshiaki Ono
  • Fujimoto, Seiji
  • Yuichi Harikane
  • Ji Hoon Kim
  • Yutaka Komiyama
  • Haruka Kusakabe
  • Chien-Hsiu Lee
  • Ken Mawatari
  • Masato Onodera
  • Yuma Sugahara
  • Kiyoto Yabe

We present the morphology and stellar population of 27 extremely metal-poor galaxies (EMPGs) at z similar to 0 with metallicities of 0.01-0.1 Z(circle dot). 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-circle dot)=6.0 n = 1.1 and a median effective radius of r (e) = 200 pc, suggesting that typical EMPGs have a very compact disk. We compare the EMPGs with z similar to 6 galaxies and local galaxies on the size-mass (r(e) -M-*) diagram, and identify that the majority of the EMPGs have an r (e) -M-* relation similar to z similar to 0 star-forming galaxies rather than z similar to 6 galaxies. Not every EMPG is a local analog of high-z young galaxies in the r(e) -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 Delta V = 101 +/- 32 km s(-1). This moderately large Delta V 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.

Original languageEnglish
Article number54
JournalAstrophysical Journal
Volume918
Issue number2
Number of pages14
ISSN0004-637X
DOIs
Publication statusPublished - 7 Sep 2021

    Research areas

  • STAR-FORMING GALAXIES, LOW-MASS GALAXIES, PHYSICAL-PROPERTIES, REIONIZATION-ERA, CLUSTER, DISCOVERY, ABUNDANCE, EMISSION, RELEASE, I.

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