TY - JOUR
T1 - The nature of massive transition galaxies in CANDELS, GAMA and cosmological simulations
AU - Pandya, Viraj
AU - Brennan, Ryan
AU - Somerville, Rachel S.
AU - Choi, Ena
AU - Barro, Guillermo
AU - Wuyts, Stijn
AU - Taylor, Edward N.
AU - Behroozi, Peter
AU - Kirkpatrick, Allison
AU - Faber, Sandra M.
AU - Primack, Joel
AU - Koo, David C.
AU - McIntosh, Daniel H.
AU - Kocevski, Dale
AU - Bell, Eric F.
AU - Dekel, Avishai
AU - Fang, Jerome J.
AU - Ferguson, Henry C.
AU - Grogin, Norman
AU - Koekemoer, Anton M.
AU - Lu, Yu
AU - Mantha, Kameswara
AU - Mobasher, Bahram
AU - Newman, Jeffrey
AU - Pacifici, Camilla
AU - Papovich, Casey
AU - van der Wel, Arjen
AU - Yesuf, Hassen M.
N1 - Publisher Copyright:
© 2017 The Authors.
PY - 2017/12
Y1 - 2017/12
N2 - We explore observational and theoretical constraints on how galaxies might transition between the 'star-forming main sequence' (SFMS) and varying 'degrees of quiescence' out to z = 3. Our analysis is focused on galaxies with stellar mass M* > 1010M⊙, and is enabled by GAMA and CANDELS observations, a semi-analytic model (SAM) of galaxy formation, and a cosmological hydrodynamical 'zoom in' simulation with momentum-driven AGN feedback. In both the observations and the SAM, transition galaxies tend to have intermediate Sérsic indices, half-light radii, and surface stellar mass densities compared to star-forming and quiescent galaxies out to z=3.We place an observational upper limit on the average population transition time-scale as a function of redshift, finding that the average high-redshift galaxy is on a 'fast track' for quenching whereas the average low-redshift galaxy is on a 'slow track' for quenching. We qualitatively identify four physical origin scenarios for transition galaxies in the SAM: oscillations on the SFMS, slow quenching, fast quenching, and rejuvenation. Quenching time-scales in both the SAM and the hydrodynamical simulation are not fast enough to reproduce the quiescent population that we observe at z ~ 3. In the SAM, we do not find a clear-cut morphological dependence of quenching time-scales, but we do predict that the mean stellar ages, cold gas fractions, SMBH (supermassive black hole) masses and halo masses of transition galaxies tend to be intermediate relative to those of star-forming and quiescent galaxies at z < 3.
AB - We explore observational and theoretical constraints on how galaxies might transition between the 'star-forming main sequence' (SFMS) and varying 'degrees of quiescence' out to z = 3. Our analysis is focused on galaxies with stellar mass M* > 1010M⊙, and is enabled by GAMA and CANDELS observations, a semi-analytic model (SAM) of galaxy formation, and a cosmological hydrodynamical 'zoom in' simulation with momentum-driven AGN feedback. In both the observations and the SAM, transition galaxies tend to have intermediate Sérsic indices, half-light radii, and surface stellar mass densities compared to star-forming and quiescent galaxies out to z=3.We place an observational upper limit on the average population transition time-scale as a function of redshift, finding that the average high-redshift galaxy is on a 'fast track' for quenching whereas the average low-redshift galaxy is on a 'slow track' for quenching. We qualitatively identify four physical origin scenarios for transition galaxies in the SAM: oscillations on the SFMS, slow quenching, fast quenching, and rejuvenation. Quenching time-scales in both the SAM and the hydrodynamical simulation are not fast enough to reproduce the quiescent population that we observe at z ~ 3. In the SAM, we do not find a clear-cut morphological dependence of quenching time-scales, but we do predict that the mean stellar ages, cold gas fractions, SMBH (supermassive black hole) masses and halo masses of transition galaxies tend to be intermediate relative to those of star-forming and quiescent galaxies at z < 3.
KW - Galaxies: bulges
KW - Galaxies: evolution
KW - Galaxies: formation
KW - Galaxies: highredshift
KW - Galaxies: star formation
KW - Galaxies: structure
UR - http://www.scopus.com/inward/record.url?scp=85052490508&partnerID=8YFLogxK
U2 - 10.1093/mnras/stx2027
DO - 10.1093/mnras/stx2027
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AN - SCOPUS:85052490508
SN - 0035-8711
VL - 472
SP - 2054
EP - 2084
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 2
ER -