The dark universe
SFB – Transregio
Bonn – Munich - Heidelberg
What is our universe made of ?
quintessence !
fire , air,
water, soil !
Basic questions , high public interest !
Ωm + X = 1
Unification of
all interactions
Superstrings
Higher dimensions
?
Ωm
: 30%
Fundamental
origin of mass
scales
Ωh
: 70%
Dark Energy
Important predictions of Dark Energy
The expansion of the Universe
accelerates today !
Structure formation :
One primordial
fluctuation- spectrum
Baryon - Peak
SDSS
galaxy –
correlation –
function
Observing Dark Energy
needs understanding
of cosmological role of
Dark Matter !
central for our TR
Research fields of TR33
Origin of Dark Energy
and Dark Matter
Time history
of
Dark Energy
Dark Matter –
Dark Energy
connection
What is Dark Energy ?
Cosmological Constant
or
Quintessence ?
Help from observation !
Cosmological Constant
- Einstein Constant λ compatible with all symmetries
 No time variation in contribution to energy
density

λ/M4 = 10-120

Why so small ?

Why important just today ?
Cosm. Const. | Quintessence
static
| dynamical
Cosmological mass scales
Only ratios of mass scales are observable !
homogeneous dark energy: ρh/M4 = 6.5 10ˉ¹²¹
matter:
ρm/M4= 3.5 10ˉ¹²¹
ρm,r/M4 ~ t -2
For matter : huge age of universe
small ratio
Same explanation for small dark energy ?
Realization :
Scalar field,
Quintessence,
K-essence, ..
New interaction !
The nature of
Dark Energy determines
the future of the
Universe …
Themes of this TR
Dark Energy
 Static or dynamic ?
 Origin of Dark Energy
 Dark Matter – cosmological context
 Interactions Dark Energy – Dark Matter
 Structure formation – cosmological aspects

Theory – simulation - observation
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Complete chain from basic theory to observation
Cosmological expertise from theoretical particle physics
and astrophysics : synergy needs effort !
Observational approaches : complementary
Leading role in large surveys:
CMB : Planck satellite
Lensing, Galaxy Power Spectra and Galaxy Clusters :
OmegaCam, Virus
Galaxy Clusters : X-rays, APEX , Supernovae surveys
Theory – simulation - observation

Theory : basic and phenomenological approaches
Includes central areas where new insights and ideas on
Dark Energy may come from :
Superstrings, higher dimensions, dilatation symmetry

Simulations : leading groups
Dynamical Dark Energy not much studied yet
New numerical challenges for inclusion of Dark Energy –
Dark Matter coupling ( fluctuations of scalar field )
Interface theory-observation
milestones

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Time history of Dark Energy
Determination of
cosmological Dark Matter characteristics and
possible coupling to Dark Energy from comparison of
observation and simulations of dark matter structures
Standard model for cosmology ? !
Time history of dark energy
h
Measure this curve !
TR working groups
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Time history of dark energy
Cosmological dark matter properties
Simulations of the universe
Cosmological information from structure formation
Gravitational lensing as probe for cosmology
Cosmology from galaxy distributions
Theory of Dark Energy
Theory of Dark Matter
some well focused – some more vague
Additional strength of TR
Close connection with several high
level organized graduate schools
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Bonn International Graduate School
Bonn IMPRS Astronomy
Heidelberg IMPRS “Astronomy and cosmic
physics”
Munich IMPRS “Astrophysics”
Postdocs and PhD students :
central for activity of TR !
Early Dark Energy
M.Doran , CW : B1
A few percent in the
early Universe
Not possible for a
cosmological
constant
1σ and 2σ limits
Doran,Karwan,..
Simple parameterization of
time-dependent dark energy fraction
CMB,SN,SDSS
Supernovae , Riess et al.
Dark Energy during structure formation
A few percent Early Dark Energy
If linear power spectrum fixed today ( σ8 ) :
More Structure at high z !
Bartelmann,Doran,…
Early quintessence slows down the
growth of structure
Little Early Dark Energy can make large effect
!
More
clusters
at
high
redshift
Cluster number
relative to ΛCDM
Two models with 4% Dark Energy
during structure formation
Fixed σ8 ( normalization dependence ! )
Challenge :
Simple, robust,
model- and parameterizationindependent
statements !
Reliable errors !