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

Understand

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, $M_*<10^9M_\odot$ (so-called mini-quenched galaxies), and one massive quiescent galaxy with $M_*=10^{10.2}M_\odot$; 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 ($EW_{0}<50$\AA) and strong Balmer breaks ($F_{\nu,4200}/F_{\nu,3500}>1.4$).