📝 SummarXiv

Abstract

We have discovered a substantial sodium doublet (Na D $\lambda\lambda$5890, 5896\AA)-traced neutral outflow in a quiescent galaxy JADES-GS-206183 at $z=1.317$ in GOODS-S field. Its JWST NIRSpec/MSA spectrum shows a significantly blueshifted and deep Na D absorption, revealing a neutral outflow with a velocity of $v_{\rm out}=828^{+79}_{-49}\,\mathrm{km\,s^{-1}}$ and a mass outflow rate of $\log(\dot{M}_{\rm out}/\mathrm{M_{\odot}\,yr^{-1}})=2.40^{+0.11}_{-0.16}$. This outflow rate exceeds that of any neutral outflows identified beyond $z\sim1$ by the same line diagnostic and is comparable with those in local galaxies with intensive star formation or luminous AGN. Nonetheless, the Paschen $\alpha$ (Pa$\alpha$) emission in the FRESCO NIRCam grism confirms that its star formation rate is low ($\mathrm{SFR_{Pa\alpha}}=10.78\pm 0.55\,\mathrm{M_{\odot}\,yr^{-1}}$), corresponding to a low specific SFR of -10.2 $\mathrm{yr^{-1}}$, 0.5 dex below the main sequence. The best-fit SED modeling based on its multi-band photometry from HST/ACS to JWST/NIRCam and the VLT/MUSE spectrum, suggests this galaxy has experienced a quiescent period lasting about one Gyr or more while seems to rejuvenate within the recent 10 Myr. Surprisingly, rest-frame optical lines indicate that the current AGN activity of JADES-GS-206183, if present, is also weak. Even though we tentatively detect a broad component of the H$\alpha$ line, it is more likely tracing the ionized outflow than an AGN. The results demonstrate that the Na D outflow in JADES-GS-206183 is highly unlikely to be driven by current star formation or nuclear activity. Instead, we propose that this outflow may be a long-lasting fossil one driven by past AGN activity, potentially co-triggered with the early phase of rejuvenation.