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

Abstract

(2016) '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., 458 (3). pp. 3181-3209. Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTWe 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 nearinfrared Hubble Space Telescope imaging. We derive light-weighted Sérsic fits in five HST bands (i 775 , z 850 ,Y 105 , J 125 , H 160 ), and find that the size decreases by ∼ 20% going from i 775 to H 160 band, consistent with recent studies. We then generate spatially resolved stellar mass maps using an empirical relationship between M * /L H 160 and (z 850 − H 160 ) and use these to derive mass-weighted Sérsic fits: the mass-weighted sizes are ∼ 41% smaller than their restframe r-band counterparts compared with an average of ∼ 12% at z ∼ 0. We attribute this evolution to the evolution in the M * /L H 160 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 semi-major axis (a), with ∇ age = d log(age)/d log(a) ∼ −0.33, while the survival of weaker colour gradients in old, local galaxies implies that metallicity gradients are also required, with ∇ Z = d log(Z)/d log(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.

The KMOS Cluster Survey (KCS). I. The Fundamental Plane and the Formation Ages of Cluster Galaxies at Redshift 1.4 < Z < 1.6*

“…All the HST data were processed as described by Chan et al (2016) and Chan et al (2017), using ASTRODRIZZLE (Gonzaga et al 2012). For this paper we used the ACS/z F850lp and WFC3 Y F105w and H F160w bands for the two clusters; see Chan et al (2016) and Chan et al (2017) for more details on the available bands.…”

“…All the HST data were processed as described by Chan et al (2016) and Chan et al (2017), using ASTRODRIZZLE (Gonzaga et al 2012). For this paper we used the ACS/z F850lp and WFC3 Y F105w and H F160w bands for the two clusters; see Chan et al (2016) and Chan et al (2017) for more details on the available bands. For XMM2215, we also used a J-band image from the Multi-object InfraRed Camera and Spectrograph (MOIRCS) at Subaru Telescope (Hilton et al 2009) with a seeing FWHM∼0 6.…”

“…We used these when we needed total magnitudes, whereas to derive aperture magnitudes, we followed Equation (3) of Skelton et al (2014) to rescale the provided total magnitudes to the original 0 7 aperture magnitudes and their errors. The use of different apertures between Skelton et al (2014) and Chan et al (2016) does not affect our selection because effective radii of most galaxies in our sample are smaller than the aperture size. Magnitudes in Skelton et al (2014) are extinction corrected using the maps by Schlafly & Finkbeiner (2011).…”

“…We perform 2D Sérsic (1968) fits, accounting simultaneously for neighboring objects and deriving the PSF from bright stars in the field. We construct catalogs of structural parameters including semimajor axis effective radii, a e , Sérsic index n, and magnitude in different ACS and WFC3 bands (see Chan et al 2016 andChan et al 2017). For each overdensity we select parameters derived in the observed band closer to the rest-frame B band of the local Coma FP (e.g., Jørgensen et al 2006).…”

“…Several papers have shown that intermediate-and highredshift passive galaxies have smaller sizes (e.g., Trujillo et al 2007;Houghton et al 2012;Newman et al 2012;Beifiori et al 2014;van der Wel et al 2014;Chan et al 2016) and higher stellar velocity dispersions (e.g., Cappellari et al 2009;Cenarro & Trujillo 2009;van Dokkum et al 2009;Belli et al 2014aBelli et al , 2014bBelli et al , 2015 than their local counterparts of the same mass or fixed cumulative number density (e.g., Brammer et al 2011;Papovich et al 2011;Muzzin et al 2013;Patel et al 2013;van Dokkum et al 2013).…”