A systematic search for dormant galaxies at z~5-7 from the JWST NIRSpec archive

Abstract

JWST has revealed a population of ``dormant'' galaxies at $z>5$ that have recently halted their star formation and are characterized by weak emission lines and significant Balmer breaks. Until now, only four such galaxies have been reported at $z>5$, three with low stellar masses, $M_{\ast }<10^9{M}_{\odot }$ (so-called mini-quenched galaxies), and one massive quiescent galaxy with $M_{\ast }=10^{10.2}{M}_{\odot }$; no such galaxy had been reported at intermediate masses. Here, we present a systematic search for dormant galaxies at $5<z<7.4$ that halted star formation at least 10 Myr before the time of observation. To do this, we made use of all the publicly available NIRSpec prism data in the DAWN JWST Archive (DJA) and selected galaxies with low H$\alpha$ equivalent widths ($E{W}_0<50$Å) and strong Balmer breaks ($F_{\nu ,4200}/F_{\nu ,3500}>1.4$). We find 14 dormant galaxies with stellar masses ranging from $10^{7.6}-10^{10.5}$, revealing an intermediate-mass population. By construction, these 14 sources are located about 1 dex below the star-forming main sequence. Their star formation histories suggest that they halted star formation between 10 and 25 Myr before the time of observation which, according to models, is comparable with the timescales of internally regulated bursts driving a ``breathing'' mode of star formation. Our results show that $\sim 1\%$ of the galaxies in the DJA are in a dormant phase of their star formation histories, and they span a wide stellar mass range. These galaxies can be empirically selected using only their spectral features in NIRSpec prism data.

Accepted in A&A

References in corpus (24)

• Mass and environment as drivers of galaxy evolution in SDSS and zCOSMOS and the origin of the Schechter function
• The James Webb Space Telescope
• Rapid formation of exponential disks and bulges at high redshift from the dynamical evolution of clump cluster and chain galaxies
• The Science Performance of JWST as Characterized in Commissioning
• H-alpha Observations of a Large Sample of Galaxies at z~2: Implications for Star Formation in High Redshift Galaxies
• HiZELS: a high redshift survey of H-alpha emitters. I: the cosmic star-formation rate and clustering at z=2.23
• Stochastic modelling of star-formation histories II: star-formation variability from molecular clouds and gas inflow
• UNCOVERing the extended strong lensing structures of Abell 2744 with the deepest JWST imaging
• RUBIES: a complete census of the bright and red distant Universe with JWST/NIRSpec
• What Causes The Formation of Disks and End of Bursty Star Formation?
• Mini-quenching of $z=4-8$ galaxies by bursty star formation
• Identification of a transition from stochastic to secular star formation around $z=9$ with JWST
• Two lensed star candidates at $z\simeq 4.8$ behind the galaxy cluster MACS J0647.7+7015
• Dust attenuation evolution in $z\sim 2$-$12$ JWST galaxies
• JADES: Differing assembly histories of galaxies -- Observational evidence for bursty SFHs and (mini-)quenching in the first billion years of the Universe
• Zapped then Napped? A rapidly quenched remnant leaker candidate with a steep spectroscopic ${\beta }_{UV}$ slope at z=8.5
• An Hα view of galaxy build-up in the first 2 Gyr: luminosity functions at z~4-6.5 from NIRCam/grism spectroscopy
• The NIRSpec Wide GTO Survey
• Gas outflows in two recently quenched galaxies at z = 4 and 7
• The THESAN-ZOOM project: Burst, quench, repeat -- unveiling the evolution of high-redshift galaxies along the star-forming main sequence
• A First Look at Spatially Resolved Star Formation at $4.8<z<6.5$ with JWST FRESCO NIRCam Slitless Spectroscopy
• Exploring over 700 massive quiescent galaxies at z = 2-7: Demographics and stellar mass functions
• Strong Balmer break objects at z ~ 7-10 uncovered with JWST
• The Hα Luminosity Function of Galaxies at z {\sim} 4.5

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