Affiliation: Centro de Astrobiología (CSIC-INTA)

Contribution: Oral

Title: Unveiling the spatially resolved ISM in the lensed galaxy A1689-zD1 at z=7.13

Abstract: Combining JWST infrared observations and ALMA observations allows us to investigate the multi-phase structure of high-redshift galaxies. The Reionization and the ISM/Stellar Origins with JWST and ALMA (RIOJA) is a JWST GO Cycle 1 program targeting bright [OIII]88m emitters at z>6 with NIRCam and NIRSpec IFU to establish the coevolution between stellar, gaseous, and dusty properties of high-redshift galaxies. In this talk, we discuss RIOJA’s results on A1689-zD1, a well-known strongly lensed sub-L* galaxy at z=7.13. It was the first galaxy with a dust continuum detection in the EoR, and it remains as one of the galaxies with the largest dataset from ALMA at this epoch. Our analysis combines spatially resolved rest-frame UV/optical NIRCam imaging and optical NIRSPec integral field spectroscopy together with ALMA detections, also spatially resolved, of [CII]158 μm and [OIII]88 μm, along with their respective dust emissions. This comprehensive dataset reveals A1689-zD1’s intricate stellar, gas, and dust structure, uncovering up to five distinct clumps with spatial offsets between the different galaxy components. The ionized gas clumps display velocity variations of ~100 km/s, suggesting a merging system. The dust and ionized gas clumps coincide, whereas only one of the rest-frame UV clumps can be associated with them. We focus on the spatial characterization of the interstellar medium (ISM) combining the rest-frame UV and FIR emission lines, deriving properties such as its electron density, temperature, SFR and metallicity. We find a subsolar metallicity (~0.2Zsun) and minimal dust attenuation despite clear ALMA dust detections. These results highlight the significance of studying lensed sub-L* galaxies like A1689-zD1, that thanks to the magnified field and increased spatial resolution, provide insights into the role of assembling galaxies and the coevolution between dust, gas and stars in the early Universe.

This contribution can be found here (pdf).