We exploit deep integral-field spectroscopic observations with KMOS/VLT of
240 star-forming disks at 0.6 < z < 2.6 to dynamically constrain their mass
budget. Our sample consists of massive ($10^9.8 M_ødot$) galaxies
with sizes $R_e 2$ kpc. By contrasting the observed velocity and
dispersion profiles to dynamical models, we find that on average the stellar
content contributes 31% of the total dynamical mass, with a significant spread
among galaxies (68th percentile range f_star ~ 16 - 60%). Including molecular
gas as inferred from CO- and dust-based scaling relations, the estimated
baryonic mass adds up to 63% of total for the typical galaxy in our sample. We
conclude that baryons make up most of the mass within the disk regions of
high-redshift star-forming galaxies, with nearly all disks at z > 2 being
strongly baryon-dominated within $R_e$. Substantial object-to-object variations
in both stellar and baryonic mass fractions are observed among the galaxies in
our sample, larger than what can be accounted for by the formal uncertainties
in their respective measurements. In both cases, the mass fractions correlate
most strongly with measures of surface density. High $\Sigma_star$ galaxies
feature stellar mass fractions closer to unity, and systems with high inferred
gas or baryonic surface densities leave less room for additional mass
components other than stars and molecular gas. Our findings can be interpreted
as more extended disks probing further (and more compact disks probing less
far) into the dark matter halos that host them. However, a non-negligible tail
of the derived baryonic mass fraction distribution reaching into the unphysical
$f_bar > 1$ regime may in addition hint at more efficient star formation in
high surface density disks than adopted in our methodology.
Description
[1603.03432] KMOS^3D: Dynamical constraints on the mass budget in early star-forming disks
cite arxiv:1603.03432Comment: Submitted to ApJ. Fig. 4 compares stellar and baryonic masses to dynamical masses. Fig. 6 and 7 show the dependence of stellar and baryonic mass fractions on redshift and surface density
%0 Generic
%1 wuyts2016kmos3d
%A Wuyts, S.
%A Schreiber, N. M. Förster
%A Wisnioski, E.
%A Genzel, R.
%A Burkert, A.
%A Bandara, K.
%A Beifiori, A.
%A Belli, S.
%A Bender, R.
%A Brammer, G. B.
%A Chan, J.
%A Davies, R.
%A Fossati, M.
%A Galametz, A.
%A Kulkarni, S. K.
%A Lang, P.
%A Lutz, D.
%A Mendel, J. T.
%A Momcheva, I. G.
%A Naab, T.
%A Nelson, E. J.
%A Saglia, R. P.
%A Seitz, S.
%A Tacconi, L. J.
%A Tadaki, K.
%A Übler, H.
%A van Dokkum, P. G.
%A Wilman, D. J.
%A Wuyts, E.
%D 2016
%K baryon budget disks high-z
%T KMOS^3D: Dynamical constraints on the mass budget in early star-forming
disks
%U http://arxiv.org/abs/1603.03432
%X We exploit deep integral-field spectroscopic observations with KMOS/VLT of
240 star-forming disks at 0.6 < z < 2.6 to dynamically constrain their mass
budget. Our sample consists of massive ($10^9.8 M_ødot$) galaxies
with sizes $R_e 2$ kpc. By contrasting the observed velocity and
dispersion profiles to dynamical models, we find that on average the stellar
content contributes 31% of the total dynamical mass, with a significant spread
among galaxies (68th percentile range f_star ~ 16 - 60%). Including molecular
gas as inferred from CO- and dust-based scaling relations, the estimated
baryonic mass adds up to 63% of total for the typical galaxy in our sample. We
conclude that baryons make up most of the mass within the disk regions of
high-redshift star-forming galaxies, with nearly all disks at z > 2 being
strongly baryon-dominated within $R_e$. Substantial object-to-object variations
in both stellar and baryonic mass fractions are observed among the galaxies in
our sample, larger than what can be accounted for by the formal uncertainties
in their respective measurements. In both cases, the mass fractions correlate
most strongly with measures of surface density. High $\Sigma_star$ galaxies
feature stellar mass fractions closer to unity, and systems with high inferred
gas or baryonic surface densities leave less room for additional mass
components other than stars and molecular gas. Our findings can be interpreted
as more extended disks probing further (and more compact disks probing less
far) into the dark matter halos that host them. However, a non-negligible tail
of the derived baryonic mass fraction distribution reaching into the unphysical
$f_bar > 1$ regime may in addition hint at more efficient star formation in
high surface density disks than adopted in our methodology.
@misc{wuyts2016kmos3d,
abstract = {We exploit deep integral-field spectroscopic observations with KMOS/VLT of
240 star-forming disks at 0.6 < z < 2.6 to dynamically constrain their mass
budget. Our sample consists of massive ($\gtrsim 10^{9.8} M_\odot$) galaxies
with sizes $R_e \gtrsim 2$ kpc. By contrasting the observed velocity and
dispersion profiles to dynamical models, we find that on average the stellar
content contributes 31% of the total dynamical mass, with a significant spread
among galaxies (68th percentile range f_star ~ 16 - 60%). Including molecular
gas as inferred from CO- and dust-based scaling relations, the estimated
baryonic mass adds up to 63% of total for the typical galaxy in our sample. We
conclude that baryons make up most of the mass within the disk regions of
high-redshift star-forming galaxies, with nearly all disks at z > 2 being
strongly baryon-dominated within $R_e$. Substantial object-to-object variations
in both stellar and baryonic mass fractions are observed among the galaxies in
our sample, larger than what can be accounted for by the formal uncertainties
in their respective measurements. In both cases, the mass fractions correlate
most strongly with measures of surface density. High $\Sigma_{star}$ galaxies
feature stellar mass fractions closer to unity, and systems with high inferred
gas or baryonic surface densities leave less room for additional mass
components other than stars and molecular gas. Our findings can be interpreted
as more extended disks probing further (and more compact disks probing less
far) into the dark matter halos that host them. However, a non-negligible tail
of the derived baryonic mass fraction distribution reaching into the unphysical
$f_{bar} > 1$ regime may in addition hint at more efficient star formation in
high surface density disks than adopted in our methodology.},
added-at = {2016-03-14T09:41:21.000+0100},
author = {Wuyts, S. and Schreiber, N. M. Förster and Wisnioski, E. and Genzel, R. and Burkert, A. and Bandara, K. and Beifiori, A. and Belli, S. and Bender, R. and Brammer, G. B. and Chan, J. and Davies, R. and Fossati, M. and Galametz, A. and Kulkarni, S. K. and Lang, P. and Lutz, D. and Mendel, J. T. and Momcheva, I. G. and Naab, T. and Nelson, E. J. and Saglia, R. P. and Seitz, S. and Tacconi, L. J. and Tadaki, K. and Übler, H. and van Dokkum, P. G. and Wilman, D. J. and Wuyts, E.},
biburl = {https://www.bibsonomy.org/bibtex/27e05c8ee51c02d1a18411fb22457254d/miki},
description = {[1603.03432] KMOS^3D: Dynamical constraints on the mass budget in early star-forming disks},
interhash = {8ae60f4f769c8f01209096b9f585264b},
intrahash = {7e05c8ee51c02d1a18411fb22457254d},
keywords = {baryon budget disks high-z},
note = {cite arxiv:1603.03432Comment: Submitted to ApJ. Fig. 4 compares stellar and baryonic masses to dynamical masses. Fig. 6 and 7 show the dependence of stellar and baryonic mass fractions on redshift and surface density},
timestamp = {2016-03-14T09:41:21.000+0100},
title = {KMOS^3D: Dynamical constraints on the mass budget in early star-forming
disks},
url = {http://arxiv.org/abs/1603.03432},
year = 2016
}