Affiliation: Centro de Astrobiología, CSIC-INTA

Contribution: Oral

Title: JWST reveals a Milky Way-like barred spiral galaxy at redshift of 3

Abstract: Understanding the cosmic evolution of the barred galaxy population is fundamental to quantifying their impact on the internal secular evolution of galaxies and dating the formation of the first dynamically cold stellar disks in the Universe. In this context, the new imaging capability provided by JWST is revolutionizing the study of high-redshift disk galaxies, unveiling for the first time their complex morphologies. In this talk, I will discuss the discovery of ceers-2112, the furthest Milky Way-like barred spiral galaxy observed to date, recently published in Nature (Costantin et al. 2023, Nature, 623, 499). Ceers-2112 is located in the EGS field, targeted as part of the CEERS ERS program. The combined analysis of HST/ACS+WFC3 and JWST/NIRCam images place the galaxy at redshift z = 3.03, thus this bar was already formed when the Universe was only 2 Gyr old. The morphological analysis of the stack NIRCam images undoubtedly discloses the presence of a bar component. Considering that stellar bars typically form in 1 Gyr, this discovery proves that baryon-dominated structures and mature stellar (and not only gaseous) disks are in place as early as ∼12 Gyrs ago (z ∼ 5), challenging the current understanding of galaxy evolution. I will put in context this discovery in the recent view of disk galaxy formation that is emerging from the first morphological studies of high-redshift galaxies obtained with JWST observations.

This contribution can be found here (pdf).