We investigate the incidence and properties of ionised gas outflows in a sample of 52 galaxies with stellar masses between 107 M and 109 M observed with ultra-deep JWST/NIRSpec MSA spectroscopy as part of the JWST Advanced Deep Extragalactic Survey (JADES). The high-spectral resolution (R2700) NIRSpec observations allowed us to identify for the first time the potential signature of outflows in the rest-frame optical nebular lines in low-mass galaxies at z > 4. The incidence fraction of ionised outflows, traced by broad components, is about 25–40%, depending on the intensity of the emission lines. The low incidence fraction might be due to both the sensitivity limit and the fact that outflows are not isotropic, but have a limited opening angle, which only results in detection when this is directed toward our line of sight. Evidence for outflows increases slightly with stellar mass and star formation rate. The median velocity and mass-loading factor (i.e. the ratio of the mass outflow rate and star formation rate) of the outflowing ionised gas are 350 km s−1 and η = 2.0+−1165, respectively. These are 1.5 and 100 times higher than the typical values observed in local dwarf galaxies. Some of these high-redshift outflows can escape the gravitational potential of the galaxy and dark matter halo and enrich the circumgalactic medium and possibly even the intergalactic medium. Our results indicate that outflows can significantly impact the star formation activity in low-mass galaxies within the first 2 Gyr of the Universe.

JADES : the incidence rate and properties of galactic outflows in low-mass galaxies across 3 < z < 9*

Carniani S.;Venturi G.;Parlanti E.;
2024

Abstract

We investigate the incidence and properties of ionised gas outflows in a sample of 52 galaxies with stellar masses between 107 M and 109 M observed with ultra-deep JWST/NIRSpec MSA spectroscopy as part of the JWST Advanced Deep Extragalactic Survey (JADES). The high-spectral resolution (R2700) NIRSpec observations allowed us to identify for the first time the potential signature of outflows in the rest-frame optical nebular lines in low-mass galaxies at z > 4. The incidence fraction of ionised outflows, traced by broad components, is about 25–40%, depending on the intensity of the emission lines. The low incidence fraction might be due to both the sensitivity limit and the fact that outflows are not isotropic, but have a limited opening angle, which only results in detection when this is directed toward our line of sight. Evidence for outflows increases slightly with stellar mass and star formation rate. The median velocity and mass-loading factor (i.e. the ratio of the mass outflow rate and star formation rate) of the outflowing ionised gas are 350 km s−1 and η = 2.0+−1165, respectively. These are 1.5 and 100 times higher than the typical values observed in local dwarf galaxies. Some of these high-redshift outflows can escape the gravitational potential of the galaxy and dark matter halo and enrich the circumgalactic medium and possibly even the intergalactic medium. Our results indicate that outflows can significantly impact the star formation activity in low-mass galaxies within the first 2 Gyr of the Universe.
2024
Settore FIS/05 - Astronomia e Astrofisica
dynamics; galaxies: evolution; galaxies: high-redshift; galaxies: ISM; galaxies: kinematics; ISM: jets and outflows
   Winds in galaxies.
   WINGS
   European Commission
   Grant Agreement n. 101040227

   Star formation quenching and feedback in galaxies throughout the cosmic epochs
   QUENCH
   European Commission
   Horizon 2020 Framework Programme
   695671

   Finding the most distant galaxies with NIRSpec guaranteed time on the James Webb Space Telescope
   FirstGalaxies
   European Commission
   Horizon 2020 Framework Programme
   789056
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11384/143463
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