We use high-resolution K-band VLT/HAWK-I imaging over 0.25 square degrees to
study the structural evolution of massive early-type galaxies since z~1.
Mass-selected samples, complete down to log(M/M_sun)~10.7 such that `typical'
L* galaxies are included at all redshifts, are drawn from pre-existing
photometric redshift surveys. We then separated the samples into different
redshift slices and classify them as late- or early-type galaxies on the basis
of their specific star-formation rate. Axis-ratio measurements for the ~400
early-type galaxies in the redshift range 0.6<z<1.8 are accurate to 0.1 or
better. The projected axis-ratio distributions are then compared with lower
redshift samples. We find strong evidence for evolution of the population
properties: early-type galaxies at z>1 are, on average, flatter than at z<1 and
the median projected axis ratio at a fixed mass decreases with redshift.
However, we also find that at all epochs z<~2 the very most massive early-type
galaxies (log(M/M_sun)>11.3) are the roundest, with a pronounced lack among
them of galaxies that are flat in projection. Merging is a plausible mechanism
that can explain both results: at all epochs merging is required for early-type
galaxies to grow beyond log(M/M_sun)~11.3, and all early types over time
gradually and partially loose their disk-like characteristics.
Beschreibung
[1211.2113] Shape Evolution of Massive Early-Type Galaxies: Confirmation of Increased Disk Prevalence at z>1
%0 Generic
%1 chang2012shape
%A Chang, Yu-Yen
%A van der Wel, Arjen
%A Rix, Hans-Walter
%A Wuyts, Stijn
%A Zibetti, Stefano
%A Ramkumar, Balasubramanian
%A Holden, Bradford P.
%D 2012
%K elliptical evolution mergers
%T Shape Evolution of Massive Early-Type Galaxies: Confirmation of
Increased Disk Prevalence at z>1
%U http://arxiv.org/abs/1211.2113
%X We use high-resolution K-band VLT/HAWK-I imaging over 0.25 square degrees to
study the structural evolution of massive early-type galaxies since z~1.
Mass-selected samples, complete down to log(M/M_sun)~10.7 such that `typical'
L* galaxies are included at all redshifts, are drawn from pre-existing
photometric redshift surveys. We then separated the samples into different
redshift slices and classify them as late- or early-type galaxies on the basis
of their specific star-formation rate. Axis-ratio measurements for the ~400
early-type galaxies in the redshift range 0.6<z<1.8 are accurate to 0.1 or
better. The projected axis-ratio distributions are then compared with lower
redshift samples. We find strong evidence for evolution of the population
properties: early-type galaxies at z>1 are, on average, flatter than at z<1 and
the median projected axis ratio at a fixed mass decreases with redshift.
However, we also find that at all epochs z<~2 the very most massive early-type
galaxies (log(M/M_sun)>11.3) are the roundest, with a pronounced lack among
them of galaxies that are flat in projection. Merging is a plausible mechanism
that can explain both results: at all epochs merging is required for early-type
galaxies to grow beyond log(M/M_sun)~11.3, and all early types over time
gradually and partially loose their disk-like characteristics.
@misc{chang2012shape,
abstract = {We use high-resolution K-band VLT/HAWK-I imaging over 0.25 square degrees to
study the structural evolution of massive early-type galaxies since z~1.
Mass-selected samples, complete down to log(M/M_sun)~10.7 such that `typical'
L* galaxies are included at all redshifts, are drawn from pre-existing
photometric redshift surveys. We then separated the samples into different
redshift slices and classify them as late- or early-type galaxies on the basis
of their specific star-formation rate. Axis-ratio measurements for the ~400
early-type galaxies in the redshift range 0.6<z<1.8 are accurate to 0.1 or
better. The projected axis-ratio distributions are then compared with lower
redshift samples. We find strong evidence for evolution of the population
properties: early-type galaxies at z>1 are, on average, flatter than at z<1 and
the median projected axis ratio at a fixed mass decreases with redshift.
However, we also find that at all epochs z<~2 the very most massive early-type
galaxies (log(M/M_sun)>11.3) are the roundest, with a pronounced lack among
them of galaxies that are flat in projection. Merging is a plausible mechanism
that can explain both results: at all epochs merging is required for early-type
galaxies to grow beyond log(M/M_sun)~11.3, and all early types over time
gradually and partially loose their disk-like characteristics.},
added-at = {2012-11-12T15:34:30.000+0100},
author = {Chang, Yu-Yen and van der Wel, Arjen and Rix, Hans-Walter and Wuyts, Stijn and Zibetti, Stefano and Ramkumar, Balasubramanian and Holden, Bradford P.},
biburl = {https://www.bibsonomy.org/bibtex/2efe32623f40b4906c5a29f7df82aa246/miki},
description = {[1211.2113] Shape Evolution of Massive Early-Type Galaxies: Confirmation of Increased Disk Prevalence at z>1},
interhash = {80a7f9eda5e2d66963674f057d0e38ac},
intrahash = {efe32623f40b4906c5a29f7df82aa246},
keywords = {elliptical evolution mergers},
note = {cite arxiv:1211.2113Comment: accepted for publication in ApJ; 11 pages; 10 figures; 4 tables},
timestamp = {2012-11-12T15:34:30.000+0100},
title = {Shape Evolution of Massive Early-Type Galaxies: Confirmation of
Increased Disk Prevalence at z>1},
url = {http://arxiv.org/abs/1211.2113},
year = 2012
}