2023/03/13 by Fudamoto, Yoshinobu, Inoue, Akio K., Coe, Dan +26
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2303.07513
We present results of [CII] 158 \rmμm emission line observations, and report the spectroscopic redshift confirmation of a strongly lensed (μ∼20) star-forming galaxy, MACS0308-zD1 at z=6.2078±0.0002. The [CII] emission line is detected with a signal-to-noise ratio >6 within the rest-frame UV bright clump of the lensed galaxy (zD1.1) and exhibits multiple velocity components; the narrow [CII] has a velocity full-width-half-maximum (FWHM) of 110±20 \rmkm/s, while broader [CII] is seen with an FWHM of 230±20 \rmkm/s. The broader [CII] component is blueshifted (-80±20 \rmkm/s) with respect to the narrow [CII] component, and has a morphology which extends beyond the UV-bright clump. We find that while the narrow [CII] emission is most likely associated with zD1.1, the broader component is possibly associated with outflowing gas. Based on the non-detection of λ\rm 158 μm dust continuum, we find that MACS0308-zD1's star-formation activity occurs in a dust-free environment with the stringent upper limit of infrared luminosity \lesssim9×108 \rm L\odot. Targeting this strongly lensed faint galaxy for follow-up ALMA and JWST observations will be crucial to characterize the details of typical galaxy growth in the early Universe.