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

PY - 2021/9/7

Y1 - 2021/9/7

N2 - 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.

AB - 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.

KW - STAR-FORMING GALAXIES

KW - LOW-MASS GALAXIES

KW - PHYSICAL-PROPERTIES

KW - REIONIZATION-ERA

KW - CLUSTER

KW - DISCOVERY

KW - ABUNDANCE

KW - EMISSION

KW - RELEASE

KW - I.

U2 - 10.3847/1538-4357/ac05bf

DO - 10.3847/1538-4357/ac05bf

M3 - Journal article

VL - 918

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 54

ER -