Gas outflows in two recently quenched galaxies at z = 4 and 7

Abstract

Outflows are a key element in the baryon cycle of galaxies, and their properties provide a fundamental test for our models of how star formation quenches in galaxies. Here we report the detection of outflowing gas in two recently quenched, massive ($M_{\star }\sim 10^{10.2}{M}_{\odot }$) galaxies at z=4.106 (NS_274) and z=7.276 (RUBIES-UDS-QG-z7) observed with JWST/NIRSpec. The outflows are traced by blue-shifted MgII absorption lines, and in the case of the z=4.1 system, also by FeII and NaI features. The spectra of the two sources are similar to those of local post-starburst galaxies, showing deep Balmer features and minimal star formation on 10 Myr timescales as traced by the lack of bright emission lines, also suggesting the absence of a strong and radiatively efficient AGN. The galaxies' SFHs are consistent with an abrupt quenching of star formation, which continued at rates of $\sim 15M_{\odot }$/yr averaged over 100 Myr timescales. Dedicated millimeter observations of NS_274 constrain its dust obscured SFR to $<12M_{\odot }$/yr. Under simple geometrical assumptions, we derive mass loading factors $\lesssim 1$ and $>10$ for the z=4.1 and z=7.3 systems, respectively, and similarly different energies carried by the outflows. Supernova feedback can account for the mass and energy of the outflow in NS_274. However, the low mass loading factor and average gas velocity suggest that the observed outflow is likely not the primary factor behind its quenching. SF-related processes seem to be insufficient to explain the extreme mass outflow rate of RUBIES-UDS-QG-z7, which would require an additional ejective mechanism such as an undetected AGN. Finally, the average outflow velocities per unit $M_{\star }$, SFR, or its surface area are consistent with those of lower-redshift post-starburst galaxies, suggesting that outflows in rapidly quenched galaxies might occur similarly across cosmic time. [Abridged]

12 pages, 7 figures + Appendix. Accepted in A&A on May 19, 2025. Data available at the links in the paper

References in corpus (39)

• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope I. Overview of the instrument and its capabilities
• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• NIRCam Performance on JWST In Flight
• The Discovery of 1000 km/s Outflows in Massive Post-starburst Galaxies at z=0.6
• Full spectrum fitting with photometry in pPXF: stellar population versus dynamical masses, non-parametric star formation history and metallicity for 3200 LEGA-C galaxies at redshift z~0.8
• A massive quiescent galaxy at redshift 4.658
• The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope II. Multi-object spectroscopy (MOS)
• An Atlas of Color-selected Quiescent Galaxies at $z>3$ in Public $JWST$ Fields
• Charting the evolution of the ages and metallicities of massive galaxies since z=0.7
• The Art of Measuring Physical Parameters in Galaxies: A Critical Assessment of Spectral Energy Distribution Fitting Techniques
• A massive galaxy that formed its stars at $z\sim 11$
• A 100-kiloparsec wind feeding the circumgalactic medium of a massive compact galaxy
• An Extremely Massive Quiescent Galaxy at $z=3.493$: Evidence of Insufficiently Rapid Quenching Mechanisms in Theoretical Models
• RUBIES: a complete census of the bright and red distant Universe with JWST/NIRSpec
• The JWST-PRIMAL Legacy Survey. A JWST/NIRSpec reference sample for the physical properties and Lyman-$\alpha$ absorption and emission of $\sim 500$ galaxies at $z=5.5-13.4$
• Galaxy Build-up in the first 1.5 Gyr of Cosmic History: Insights from the Stellar Mass Function at $z\sim 4-9$ from JWST NIRCam Observations
• A population of faint, old, and massive quiescent galaxies at 3 < z < 4 revealed by JWST NIRSpec Spectroscopy
• Star Formation Shut Down by Multiphase Gas Outflow in a Galaxy at a Redshift of 2.45
• CLASSY IV: Exploring UV diagnostics of the interstellar medium in local high-$z$ analogs at the dawn of the JWST era
• CLASSY III: The Properties of Starburst-Driven Warm Ionized Outflows
• JWST Reveals Widespread AGN-Driven Neutral Gas Outflows in Massive z ~ 2 Galaxies
• The fundamental signature of star formation quenching from AGN feedback: A critical dependence of quiescence on supermassive black hole mass not accretion rate
• Tracing the Quenching Journey across Cosmic Time
• An empirical study of dust properties at the earliest epochs
• The Mass Scale of High-Redshift Galaxies: Virial Mass Estimates Calibrated with Stellar Dynamical Models from LEGA-C
• Multi-phase outflows in post starburst E+A galaxies -- I. General sample properties and the prevalence of obscured starbursts
• Multi-phase outflows in post starburst E+A galaxies -- II. A direct connection between the neutral and ionized outflow phases
• MAGAZ3NE: High Stellar Velocity Dispersions for Ultra-Massive Quiescent Galaxies at $z\gtrsim 3$
• An exquisitely deep view of quenching galaxies through the gravitational lens: Stellar population, morphology, and ionized gas
• An AGN with an ionized gas outflow in a massive quiescent galaxy in a protocluster at $\mathbf{z}=3.09$
• Black holes regulate cool gas accretion in massive galaxies
• The cosmic build-up of dust and metals. Accurate abundances from GRB-selected star-forming galaxies at $1.7<z<6.3$
• A photo-z cautionary tale: Redshift confirmation of COSBO-7 at z=2.625
• Spectroscopic Confirmation of an Ultra-Massive Galaxy in a Protocluster at $z\sim 4.9$
• On the origin of star formation quenching in massive galaxies at $z\gtrsim 3$ in the cosmological simulations IllustrisTNG
• High-velocity outflows persist up to 1 Gyr after a starburst in recently-quenched galaxies at z > 1
• Evolution of Gas Flows along the Starburst to Post-Starburst to Quiescent Galaxy Sequence
• Black hole mass of a quiescent galaxy hosting a Type 1 AGN at z=2.09: Implications for black hole - galaxy co-evolution and AGN quenching at high redshift

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