2025/10/10 by Eleonora Parlanti, G. Tozzi, Giulia Tozzi +80
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #astro-ph.GA
paper · pdf · doi:10.48550/arxiv.2510.09820
23 pages, 16 figures, submitted to A&A
openalex publication_date 2025/10/10 · openalex created_date 2025/10/15 · arxiv created 2026/07/30 · arxiv updated 2026/07/31 · openalex updated_date 2026/08/01
Cosmic noon represents the prime epoch of galaxy assembly, and a sweet spot for observations with the James Webb Telescope (JWST) and ground-based near-IR integral-field unit (IFU) spectrographs. This work analyses JWST NIRSpec Micro Shutter Array (MSA), NIRCam Wide Field Slitless Spectroscopy (WFSS) of K20-ID7, a large spiral, star-forming (SF) galaxy at z=2.2, with evidence for radial gas inflows. By exploiting the synergy with ground-based IFU ERIS observations, we conduct a comprehensive and resolved study of the interstellar medium (ISM) and stellar properties, from rest optical to near-IR, via emission-line diagnostics, resolved spectral energy distribution (SED) fitting of high-resolution imaging, and Paβ line detection in NIRCam WFSS data. Our analysis reveals massive (M⋆≃(0.67-3.5)×109 M\odot) SF clumps with star formation rates (SFRs) ~3-24 M\odot/yr, and quite low dust attenuation (AV≃0.4), electron density (ne<300 cm-3), and ionisation (log(U)≃ -3.0). The central bulge turns out to be modestly massive (M⋆=(7±3)×109 M\odot), heavily obscured (AV=6.43±0.55), and likely to have formed most of its stellar mass in the past (SFR=82±42 M\odot/yr over the last 100 Myr), yet still forming stars at a lower rate (SFR=12±8 M\odot/yr over the last 10 Myr). We infer a metallicity 12+log(O/H)~8.54 and an apparent enhancement of the N/O abundance (log(N/O)≃ -1.0) in all distinct galaxy regions, a likely consequence of dilution effects due to radial inflows of metal-poor gas. We measure a sub-solar sulfur abundance (log(S/O)≃-1.9). Finally, the radial stellar age profile reveals older stellar populations in the inner galaxy regions compared to the outskirts, pointing to an inside-out growth of K20-ID7.