DeepDive: A deep dive into the physics of the first massive quiescent galaxies in the Universe

@article{ito2026deepdive,
  title = {{DeepDive: A deep dive into the physics of the first massive quiescent galaxies in the Universe}},
  author = {Kei Ito and Francesco M. Valentino and G. Brammer and M. L. Hamadouche and Katherine E. Whitaker and Vasily Kokorev and P. Zhu and T. Kakimoto and Po-Feng Wu and Jacqueline Antwi-Danso and W. M. Baker and Daniel Ceverino and Andreas L. Faisst and Marion Farcy and Seiji Fujimoto and Anna Gallazzi and Steven Gillman and Rashmi Gottumukkala and K. E. Heintz and Michaela Hirschmann and Christian Kragh Jespersen and Mariko Kubo and Minju Lee and G. Magdis and Masato Onodera and R. Shimakawa and M. Tanaka and Sune Toft and John R. Weaver},
  journal = {Astronomy and Astrophysics},
  year = {2026},
  month = may,
  doi = {10.1051/0004-6361/202556137},
  url = {https://doi.org/10.1051/0004-6361/202556137},
  note = {CC BY},
}

TY  - JOUR
TI  - DeepDive: A deep dive into the physics of the first massive quiescent galaxies in the Universe
AU  - Kei Ito
AU  - Francesco M. Valentino
AU  - G. Brammer
AU  - M. L. Hamadouche
AU  - Katherine E. Whitaker
AU  - Vasily Kokorev
AU  - P. Zhu
AU  - T. Kakimoto
AU  - Po-Feng Wu
AU  - Jacqueline Antwi-Danso
AU  - W. M. Baker
AU  - Daniel Ceverino
AU  - Andreas L. Faisst
AU  - Marion Farcy
AU  - Seiji Fujimoto
AU  - Anna Gallazzi
AU  - Steven Gillman
AU  - Rashmi Gottumukkala
AU  - K. E. Heintz
AU  - Michaela Hirschmann
AU  - Christian Kragh Jespersen
AU  - Mariko Kubo
AU  - Minju Lee
AU  - G. Magdis
AU  - Masato Onodera
AU  - R. Shimakawa
AU  - M. Tanaka
AU  - Sune Toft
AU  - John R. Weaver
PY  - 2026
DA  - 2026/05/19
JO  - Astronomy and Astrophysics
DO  - 10.1051/0004-6361/202556137
UR  - https://doi.org/10.1051/0004-6361/202556137
AB  - We present the DeepDive program, in which we obtained deep (1 − 3 hours) JWST/NIRSpec G235M/F170LP spectra for ten primary massive (log( M ★ / M ⊙ ) = 10.8 − 11.5) quiescent galaxies at z ∼ 3 − 4. A novel reduction procedure was used to extend the nominal wavelength coverage of G235M beyond H α and [N II] at z ∼ 4, revealing weak, narrow H α lines indicative of low star formation rates (SFR ∼ 0 − 5 M ⊙ yr −1 ). Two out of ten primary targets have broad H α lines, indicating the presence of active galactic nuclei. We also conducted an archival search of quiescent galaxies observed with NIRSpec gratings in the DAWN JWST Archive, which provides a statistical context for interpreting the DeepDive targets. This archival search provided a spectroscopic sample of 126 quiescent galaxies spanning 1 < z < 5, selected by high D n 4000, UVJ color, or low specific star formation rate (more than one dex lower than that of the star formation main sequence), and covering more than an order of magnitude in stellar mass. This sample allowed us to revisit the sample from the different selections, finding ∼90% overlap between these criteria. The total sample of 136 quiescent galaxies constructed in this study shows that those at z ∼ 3 − 5, including the DeepDive targets, typically exhibit weaker 4000 Å breaks and bluer colors than their lower-redshift counterparts, indicating generally younger stellar populations. Stacked spectra of sources grouped by the D n 4000 index reveal faint iron and magnesium absorption line features in the stellar continuum even for the low D n 4000 ( D n 4000 < 1.35) subsample at high redshift ( z ∼ 3). In addition, higher D n 4000 subsamples show fainter nebular emission lines. These results demonstrate that medium-resolution NIRSpec spectroscopy is essential for robustly characterizing the diversity and evolution of early quiescent galaxies. The large sample constructed in this paper will allow a statistical census of the properties of quiescent galaxies at high redshift to be obtained. All photometric and spectroscopic data from this study have been made publicly available.
SN  - 0004-6361
SN  - 1432-0746
ER  -