TY - JOUR
T1 - Recent star formation in a massive slowly quenched lensed quiescent galaxy at z=1.88
AU - Akhshik, Mohammad
AU - Whitaker, Katherine E.
AU - Leja, Joel
AU - Mahler, Guillaume
AU - Sharon, Keren
AU - Brammer, Gabriel
AU - Toft, Sune
AU - Bezanson, Rachel
AU - Man, Allison
AU - Nelson, Erica J.
AU - Pacifici, Camilla
AU - Wellons, Sarah
AU - Williams, Christina C.
N1 - Publisher Copyright:
© 2021. The American Astronomical Society.
PY - 2021/1/20
Y1 - 2021/1/20
N2 - In this Letter, we reconstruct the formation pathway of MRG-S0851, a massive, logM*M⊙ = 11.02 ±0.04, strongly lensed, red galaxy at z = 1.883 ± 0.001. While the global photometry and spatially resolved outskirts of MRG-S0851 imply an early formation scenario with a slowly decreasing or constant star formation history, a joint fit of 2D grism spectroscopy and photometry reveals a more complex scenario: MRG-S0851 is likely to be experiencing a centrally concentrated rejuvenation in the inner ∼1 kpc in the last ∼100 Myr of evolution. We estimate 0.5 ± 0.1% of the total stellar mass is formed in this phase. Rejuvenation episodes are suggested to be infrequent for massive galaxies at z ∼ 2, but as our analyses indicate, more examples of complex star formation histories may yet be hidden within existing data. By adding an FUV color criterion to the standard U-V/V-J diagnostic-thereby heightening our sensitivity to recent star formation-we show that we can select populations of galaxies with similar spectral energy distributions to that of MRG-S0851, but note that deep follow-up spectroscopic observations and/or spatially resolved analyses are necessary to robustly confirm the rejuvenation of these candidates. Using our criteria with MRG-S0851 as a prototype, we estimate that ∼1% of massive quiescent galaxies at 1 < z < 2 are potentially rejuvenating.
AB - In this Letter, we reconstruct the formation pathway of MRG-S0851, a massive, logM*M⊙ = 11.02 ±0.04, strongly lensed, red galaxy at z = 1.883 ± 0.001. While the global photometry and spatially resolved outskirts of MRG-S0851 imply an early formation scenario with a slowly decreasing or constant star formation history, a joint fit of 2D grism spectroscopy and photometry reveals a more complex scenario: MRG-S0851 is likely to be experiencing a centrally concentrated rejuvenation in the inner ∼1 kpc in the last ∼100 Myr of evolution. We estimate 0.5 ± 0.1% of the total stellar mass is formed in this phase. Rejuvenation episodes are suggested to be infrequent for massive galaxies at z ∼ 2, but as our analyses indicate, more examples of complex star formation histories may yet be hidden within existing data. By adding an FUV color criterion to the standard U-V/V-J diagnostic-thereby heightening our sensitivity to recent star formation-we show that we can select populations of galaxies with similar spectral energy distributions to that of MRG-S0851, but note that deep follow-up spectroscopic observations and/or spatially resolved analyses are necessary to robustly confirm the rejuvenation of these candidates. Using our criteria with MRG-S0851 as a prototype, we estimate that ∼1% of massive quiescent galaxies at 1 < z < 2 are potentially rejuvenating.
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U2 - 10.3847/2041-8213/abd416
DO - 10.3847/2041-8213/abd416
M3 - Article
AN - SCOPUS:85100304119
SN - 2041-8205
VL - 907
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - abd416
ER -