Subaru/FOCAS IFU revealed the metallicity gradient of a local extremely metal-poor galaxy
Abstract
We present the first measurement of the metallicity gradient in extremely metal-poor galaxies (EMPGs). With Subaru/Faint Object Camera And Spectrograph (FOCAS) Integral Field Unit (IFU), we have observed a nearby, low-mass EMPG, HSC J1631+4426, whose oxygen abundance and stellar mass are known to be 12 + log (O/H) = 6.9 and log10(M*/M⊙) = 5.8, respectively. The measured metallicity gradient is -0.36 ± 0.04 dex kpc-1 corresponding to -0.049 ± 0.006 dex$\:R_\mathrm{e}^{-1}$ for the continuum effective radius of Re = 0.14 kpc. Our observation has successfully demonstrated that three-dimensional spectroscopy with 8 m-class telescopes is powerful enough to reveal the metallicity distribution in local EMPGs, providing precious information on the baryon cycle in local analogs of primordial galaxies in the early Universe.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- December 2021
- DOI:
- 10.1093/pasj/psab100
- arXiv:
- arXiv:2110.05030
- Bibcode:
- 2021PASJ...73.1631K
- Keywords:
-
- galaxies: abundances;
- galaxies: dwarf;
- galaxies: evolution;
- galaxies: individual (HSC J1631+4426);
- galaxies: ISM;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- PASJ accepted, 7 pages, 4 figures