TY - JOUR
T1 - Marta
T2 - The connection between chemical enrichment, feedback, and dust in a Wolf-Rayet galaxy at z${\sim}$2
AU - Curti, Mirko
AU - Cataldi, Elisa
AU - Belfiore, Francesco
AU - Moreschini, Bianca
AU - Arnaboldi, Magda
AU - Chruślińska, Martyna
AU - Mannucci, Filippo
AU - Marconi, Alessandro
AU - D'Amato, Quirino
AU - Carniani, Stefano
AU - Baker, William M.
AU - Cia, Annalisa De
AU - Kumari, Nimisha
AU - Amiri, Amirnezam
AU - Cresci, Giovanni
AU - Kobayashi, Chiaki
AU - Cullen, Fergus
AU - Feltre, Anna
AU - Maiolino, Roberto
AU - Shivaei, Irene
N1 - © The Authors 2026. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0)
PY - 2026/6/30
Y1 - 2026/6/30
N2 - We present the analysis of the stellar and interstellar medium (ISM) properties of MARTA-4327, a star-forming galaxy at z=2.224 observed by means of deep JWST/NIRSpec spectroscopy in both medium- and high-resolution gratings as part of the "Measuring Abundances at high Redshift with the Te Approach" (MARTA) programme. We report one of the highest-redshift detections of the Wolf-Rayet (WR) blue and red bumps in a non-lensed system. The broad He ii$λ$4686 feature is consistent with a young (${\sim 5-6}$ Myr) burst dominated by WN stars, although both SSP models and empirical templates struggle to reproduce the nitrogen stellar features at ${\approx}$ 4640 A. Based on the relative strength of the available optical stellar features, we disfavor the presence of very massive stars (VMS) in this system. Elemental abundance ratios such as Ne/O, N/O, and Ar/O align with observations of local star-forming galaxies (including WR galaxies), suggesting that any impact of the WR population on the chemical enrichment of the ISM is strongly localized. However, the gas-phase Fe/O ratio appears enhanced compared to local galaxies of similar metallicity, which we interpret as evidence for reduced Fe depletion onto dust grains, possibly linked to localized destruction in WR-driven wind environments. In addition, we detect a broad and blueshifted (~70 km/s) H$α$ component, revealing the presence of an ionized outflow with a mass loading factor ${η\sim 0.2}$. Finally, we report the robust detection of O I$λ$8446 emission (among the firsts at high redshift), which we interpret as originating from Ly$β$ fluorescence and/or collisional excitation in dense clumps. Overall, MARTA-4327 represents a unique system for studying the role of massive stars in shaping the ISM in galaxies at Cosmic Noon.
AB - We present the analysis of the stellar and interstellar medium (ISM) properties of MARTA-4327, a star-forming galaxy at z=2.224 observed by means of deep JWST/NIRSpec spectroscopy in both medium- and high-resolution gratings as part of the "Measuring Abundances at high Redshift with the Te Approach" (MARTA) programme. We report one of the highest-redshift detections of the Wolf-Rayet (WR) blue and red bumps in a non-lensed system. The broad He ii$λ$4686 feature is consistent with a young (${\sim 5-6}$ Myr) burst dominated by WN stars, although both SSP models and empirical templates struggle to reproduce the nitrogen stellar features at ${\approx}$ 4640 A. Based on the relative strength of the available optical stellar features, we disfavor the presence of very massive stars (VMS) in this system. Elemental abundance ratios such as Ne/O, N/O, and Ar/O align with observations of local star-forming galaxies (including WR galaxies), suggesting that any impact of the WR population on the chemical enrichment of the ISM is strongly localized. However, the gas-phase Fe/O ratio appears enhanced compared to local galaxies of similar metallicity, which we interpret as evidence for reduced Fe depletion onto dust grains, possibly linked to localized destruction in WR-driven wind environments. In addition, we detect a broad and blueshifted (~70 km/s) H$α$ component, revealing the presence of an ionized outflow with a mass loading factor ${η\sim 0.2}$. Finally, we report the robust detection of O I$λ$8446 emission (among the firsts at high redshift), which we interpret as originating from Ly$β$ fluorescence and/or collisional excitation in dense clumps. Overall, MARTA-4327 represents a unique system for studying the role of massive stars in shaping the ISM in galaxies at Cosmic Noon.
KW - astro-ph.GA
U2 - 10.1051/0004-6361/202558145
DO - 10.1051/0004-6361/202558145
M3 - Article
SN - 0004-6361
VL - 710
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
M1 - A18
ER -