Professor Andrew Bunker

Abstract:

We report the discovery of a substantial sodium doublet (Na D λλ5890, 5896)—traced neutral outflow in the quiescent galaxy JADES-GS-206183 at z = 1.317. Its JWST/NIRSpec-Microshutter Array spectrum shows a deep, blueshifted Na D absorption, revealing a neutral outflow with vout=828−49+79kms−1 and a mass outflow rate of log(Ṁout/M⊙yr−1)=2.40−0.16+0.11 . This outflow rate exceeds that of any neutral outflows identified beyond z ∼ 1 by the same line and is comparable with those in local galaxies with intensive star formation (SF) or luminous active galactic nuclei (AGN). JADES-GS-206183 is also a peculiar quiescent galaxy with a spiral+bar morphology, high dust attenuation (AV = 2.27 ± 0.23 mag). Paschen α (Paα) emission from the FRESCO NIRCam grism confirms its low star formation rate (SFRPaα = 10.78 ± 0.55 M⊙ yr−1), placing it 0.5 dex below the main sequence ( log(sSFRyr−1)=−10.2 ). Despite the systematics introduced by different SF history priors, the spectral energy distribution modeling, combining Hubble Space Telescope-to-NIRCam photometry with the Very Large Telescope/MUSE spectrum, suggests that JADES-GS-206183 experienced an older episode of SF 0.5–2 Gyr ago and a possible rejuvenation within the recent ∼10 Myr. Moreover, 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 Hα line, it likely traces an ionized outflow rather than an AGN. The results demonstrate that the Na D outflow in JADES-GS-206183 is highly unlikely to be driven by current SF or nuclear activity. Instead, it may represent a long-lasting fossil outflow from past AGN activity, potentially cotriggered with the early phase of rejuvenation.