2021ApJ...907L...8A -
Astrophys. J., 907, L8-L8 (2021/January-3)
Recent star formation in a massive slowly quenched lensed quiescent galaxy at z = 1.88.
AKHSHIK M., WHITAKER K.E., LEJA J., MAHLER G., SHARON K., BRAMMER G., TOFT S., BEZANSON R., MAN A., NELSON E.J., PACIFICI C., WELLONS S. and WILLIAMS C.C.
Abstract (from CDS):
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.
Abstract Copyright:
© 2021. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Galaxy formation - High-redshift galaxies - Galaxy stellar content - Galaxy quenching
Simbad objects:
1
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