TY - JOUR

T1 - Sizes, colour gradients and resolved stellar mass distributions for the massive cluster galaxies in XMMUJ2235-2557 at z = 1.39

AU - Chan, Jeffrey C C

AU - Beifiori, Alessandra

AU - Trevor Mendel, J.

AU - Saglia, Roberto P.

AU - Bender, Ralf

AU - Fossati, Matteo

AU - Galametz, Audrey

AU - Wegner, Michael

AU - Wilman, David J.

AU - Cappellari, Michele

AU - Davies, Roger L.

AU - Houghton, Ryan C W

AU - Prichard, Laura J.

AU - Lewis, Ian J.

AU - Sharples, Ray

AU - Stott, John P.

N1 - This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version Jeffrey C. C. Chan, Alessandra Beifiori, J. Trevor Mendel, Roberto P. Saglia, Ralf Bender, Matteo Fossati, Audrey Galametz, Michael Wegner, David J. Wilman, Michele Cappellari, Roger L. Davies, Ryan C. W. Houghton, Laura J. Prichard, Ian J. Lewis, Ray Sharples, John P. Stott; Sizes, colour gradients and resolved stellar mass distributions for the massive cluster galaxies in XMMUJ2235-2557 at z = 1.39, Monthly Notices of the Royal Astronomical Society, Volume 458, Issue 3, 21 May 2016, Pages 3181–3209, https://doi.org/10.1093/mnras/stw502 is available online at: https://academic.oup.com/mnras/article-lookup/doi/10.1093/mnras/stw502

PY - 2016/5/21

Y1 - 2016/5/21

N2 - We analyse the sizes, colour gradients and resolved stellar mass distributions for 36 massive and passive galaxies in the cluster XMMUJ2235-2557 at z = 1.39 using optical and near-infrared Hubble Space Telescope (HST) imaging. We derive light-weighted Sérsic fits in five HST bands (i775, z850, Y105, J125, H160), and find that the size decreases by ~20 per cent going from i775 to H160 band, consistent with recent studies. We then generate spatially resolved stellar mass maps using an empirical relationship between M*/LH160 and (z850- H160) and use these to derive mass-weighted Sérsic fits: the mass-weighted sizes are ~41 per cent smaller than their rest-frame r-band counterparts compared with an average of ~12 per cent at z ~ 0. We attribute this evolution to the evolution in the M*/LH160 and colour gradient. Indeed, as expected, the ratio of mass-weighted to light-weighted size is correlated with the M*/L gradient, but is also mildly correlated with the mass surface density and mass-weighted size. The colour gradients (∇z- H) are mostly negative, with a median value of ~0.45 mag dex-1, twice the local value. The evolution is caused by an evolution in age gradients along the semimajor axis (a), with ∇age = dlog (age)/dlog (a) ~- 0.33, while the survival of weaker colour gradients in old, local galaxies implies that metallicity gradients are also required, with ∇Z = dlog (Z)/dlog (a) ~- 0.2. This is consistent with recent observational evidence for the inside-out growth of passive galaxies at high redshift, and favours a gradual mass growth mechanism, such as minor mergers.

AB - We analyse the sizes, colour gradients and resolved stellar mass distributions for 36 massive and passive galaxies in the cluster XMMUJ2235-2557 at z = 1.39 using optical and near-infrared Hubble Space Telescope (HST) imaging. We derive light-weighted Sérsic fits in five HST bands (i775, z850, Y105, J125, H160), and find that the size decreases by ~20 per cent going from i775 to H160 band, consistent with recent studies. We then generate spatially resolved stellar mass maps using an empirical relationship between M*/LH160 and (z850- H160) and use these to derive mass-weighted Sérsic fits: the mass-weighted sizes are ~41 per cent smaller than their rest-frame r-band counterparts compared with an average of ~12 per cent at z ~ 0. We attribute this evolution to the evolution in the M*/LH160 and colour gradient. Indeed, as expected, the ratio of mass-weighted to light-weighted size is correlated with the M*/L gradient, but is also mildly correlated with the mass surface density and mass-weighted size. The colour gradients (∇z- H) are mostly negative, with a median value of ~0.45 mag dex-1, twice the local value. The evolution is caused by an evolution in age gradients along the semimajor axis (a), with ∇age = dlog (age)/dlog (a) ~- 0.33, while the survival of weaker colour gradients in old, local galaxies implies that metallicity gradients are also required, with ∇Z = dlog (Z)/dlog (a) ~- 0.2. This is consistent with recent observational evidence for the inside-out growth of passive galaxies at high redshift, and favours a gradual mass growth mechanism, such as minor mergers.

KW - Galaxies: Clusters: General

KW - Galaxies: Elliptical and lenticular, cD

KW - Galaxies: Formation

KW - Galaxies: Fundamental parameters

KW - Galaxies: High-redshift

KW - Galaxy: Evolution

U2 - 10.1093/mnras/stw502

DO - 10.1093/mnras/stw502

M3 - Journal article

AN - SCOPUS:84964791002

VL - 458

SP - 3181

EP - 3209

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -