TY - JOUR
T1 - The new galaxy evolution paradigm revealed by the Herschel Surveys
AU - Eales, Stephen
AU - Smith, Dan
AU - Bourne, Nathan
AU - Loveday, Jon
AU - Rowlands, Kate
AU - Werf, Paul van der
AU - Driver, Simon
AU - Dunne, Loretta
AU - Dye, Simon
AU - Furlanetto, Cristina
AU - Ivison, R. J.
AU - Maddox, Steve
AU - Robotham, Aaron
AU - Smith, Matthew W. L.
AU - Taylor, Edward N.
AU - Valiante, Elisabetta
AU - Wright, Angus
AU - Cigan, Philip
AU - Zotti, Gianfranco De
AU - Jarvis, Matt J.
AU - Marchetti, Lucia
AU - Michałowski , Michał J.
AU - Phillipps, Steve
AU - Viaene, Sebastian
AU - Vlahakis, Catherine
PY - 2018/1
Y1 - 2018/1
N2 - The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys which presents a challenge for galaxy-evolution models. The Herschel surveys reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a single Galaxy Sequence (GS) rather than a star-forming ‘main sequence’ and a separate region of ‘passive’ or ‘red-and-dead’ galaxies. The form of the GS is now clearer because far-infrared surveys such as the Herschel ATLAS pick up a population of optically red star-forming galaxies that would have been classified as passive using most optical criteria. The space-density of this population is at least as high as the traditional star-forming population. By stacking spectra of H-ATLAS galaxies over the redshift range 0.001 < z < 0.4, we show that the galaxies responsible for the rapid low-redshift evolution have high stellar masses, high star-formation rates but, even several billion years in the past, old stellar populations – they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today. The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution. We propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population.
AB - The Herschel Space Observatory has revealed a very different galaxyscape from that shown by optical surveys which presents a challenge for galaxy-evolution models. The Herschel surveys reveal (1) that there was rapid galaxy evolution in the very recent past and (2) that galaxies lie on a single Galaxy Sequence (GS) rather than a star-forming ‘main sequence’ and a separate region of ‘passive’ or ‘red-and-dead’ galaxies. The form of the GS is now clearer because far-infrared surveys such as the Herschel ATLAS pick up a population of optically red star-forming galaxies that would have been classified as passive using most optical criteria. The space-density of this population is at least as high as the traditional star-forming population. By stacking spectra of H-ATLAS galaxies over the redshift range 0.001 < z < 0.4, we show that the galaxies responsible for the rapid low-redshift evolution have high stellar masses, high star-formation rates but, even several billion years in the past, old stellar populations – they are thus likely to be relatively recent ancestors of early-type galaxies in the Universe today. The form of the GS is inconsistent with rapid quenching models and neither the analytic bathtub model nor the hydrodynamical EAGLE simulation can reproduce the rapid cosmic evolution. We propose a new gentler model of galaxy evolution that can explain the new Herschel results and other key properties of the galaxy population.
KW - Galaxies: evolution
U2 - 10.1093/mnras/stx2548
DO - 10.1093/mnras/stx2548
M3 - Article
SN - 0035-8711
VL - 474
SP - 3507
EP - 3524
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -