GA-NIFS: Multiphase analysis of a star-forming galaxy at <i>z</i> ∼ 5.5
In this study, we present a detailed multiphase analysis of HZ4, a main-sequence star-forming galaxy at z ∼ 5.5, known for being a turbulent rotating disk and having a detection of a [C II ] outflow in the ALMA observations. We exploited JWST/NIRSpec observations in the integral field spectroscopy mode with low- and high-spectral resolution which allow us, for the first time, to spatially resolve the rest-frame UV and optical emission of the galaxy to investigate the galaxy properties. In particular, the high-resolution dataset allowed us to study the kinematics of the ionized gas phase, and the conditions of the interstellar medium, such as the excitation mechanism, dust attenuation, and metallicity. The lower spectral-resolution observations allowed us to study the continuum emission and infer the stellar populations’ ages and properties. Our findings suggest that HZ4 is a galaxy merger rather than a rotating disk as previously inferred from lower-resolution [C II ] data. The merger is associated with an extended broad, blueshifted emission, potentially indicative of an outflow originating from a region of intense star formation and extending up to 4 kpc. In light of these new observations, we reanalyzed the ALMA data to compare the multiphase gas properties. If we interpret the broad components seen in [C II ] and [O III ] λ 5007 Å as outflows, the neutral and ionized components are co-spatial, and the mass loading factor of the ionized phase is significantly lower than that of the neutral phase, aligning with trends observed in multiphase systems at lower redshifts. Nonetheless, additional observations and larger statistical samples are essential to determine the role of mergers and outflows in the early Universe and to clarify the origin of the broad emission components observed in this system.
Authors
- G. Cresci (ORCID: https://orcid.org/0000-0002-5281-1417)
- Francesco D’Eugenio (ORCID: https://orcid.org/0000-0003-2388-8172)
- Santiago Arribas (ORCID: https://orcid.org/0000-0001-7997-1640)
- Bruno Rodríguez Del Pino (ORCID: https://orcid.org/0000-0001-5171-3930)
- Michele Perna (ORCID: https://orcid.org/0000-0002-0362-5941)
- R. Maiolino (ORCID: https://orcid.org/0000-0002-4985-3819)
- Stefano Carniani (ORCID: https://orcid.org/0000-0002-6719-380X)
- Rodrigo Herrera-Camus (ORCID: https://orcid.org/0000-0002-2775-0595)
- Gareth C. Jones (ORCID: https://orcid.org/0000-0002-0267-9024)
- Pablo G. Pérez‐González (ORCID: https://orcid.org/0000-0003-4528-5639)
- S. Charlot (ORCID: https://orcid.org/0000-0003-3458-2275)
- Mirko Curti (ORCID: https://orcid.org/0000-0002-2678-2560)
- Hannah Übler (ORCID: https://orcid.org/0000-0003-4891-0794)
- Isabella Lamperti (ORCID: https://orcid.org/0000-0003-3336-5498)
- Andrew J. Bunker (ORCID: https://orcid.org/0000-0002-8651-9879)
- Giacomo Venturi (ORCID: https://orcid.org/0000-0001-8349-3055)
- Eleonora Parlanti (ORCID: https://orcid.org/0000-0002-7392-7814)
- Sandra Zamora
- Torsten Böker
Institutions
- Centre National de la Recherche Scientifique (FR)
- European Southern Observatory (DE)
- Scuola Normale Superiore (IT)
- University of Concepción (CL)
- University of Cambridge (GB)
- Arcetri Astrophysical Observatory (IT)
- Institut d'Astrophysique de Paris (FR)
- Sorbonne Université (FR)
- University of Oxford (GB)
- Centro de Astrobiología (ES)
- Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (IT)
- University of Florence (IT)
- University College London (GB)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2025-02-05
- DOI
- https://doi.org/10.1051/0004-6361/202451692
- Citations
- 17
- Primary Topic
- Astronomy and Astrophysical Research
- Type
- article
- Field-Weighted Citation Impact
- 20.26
Funders
- National Science Foundation
- UK Research and Innovation
- National Radio Astronomy Observatory
- European Commission
- Korea Astronomy and Space Science Institute
- Isaac Newton Trust
- Ministerio de Ciencia e Innovación
- National Astronomical Observatory of Japan
- Science and Technology Facilities Council
- National Institutes of Natural Sciences
- Agencia Estatal de Investigación