Fakultäten » Mathematisch-naturwissenschaftliche Fakultät » Physik-Institut » Prof. Dr. Philippe Jetzer » Jetzer

Completed research project

Title / Titel Limits on decaying dark energy density models from the
CMB temperature-redshift relation
PDF Abstract (PDF, 14 KB)
Summary / Zusammenfassung The nature of the dark energy is still a mystery and several models have been proposed to
explain it. We considered a phenomenological model for dark energy decay into photons
and particles as proposed in a paper by Lima (Phys. Rev. D 54, 2571, 1996). He studied
the thermodynamic aspects of decaying dark energy models in particular in the case
of a continuous photon creation and/or disruption. Following his approach, we derived
a temperature redshift relation for the CMB which depends on the effective equation
of state weff and on the “adiabatic index” . Comparing our relation with the
data on the CMB temperature as a function of the redshift obtained from Sunyaev-
Zel’dovich observations and at higher redshift from quasar absorption line spectra, we
find weff = −0.97 ± 0.034, adopting for the adiabatic index ° = 4/3, in good agreement
with current estimates and still compatible with weff = −1 (this latter value implying
that the dark energy content being constant in time).
In a further paper, we discussed
our previous results within a more detailed theoretical background and by testing our
model with an updated collection of data. We also discussed the combined temperature
measurements with data from different kind of observations, like distance moduli of Supernovae
Ia, observations of the CMB anisotropy and the large scale structure, together
with observational Hubble parameter estimations.
Publications / Publikationen Gen. Rel. Grav., Volume 43, (2011), pp. 1083

Phys. Rev. D., Volume 84, (2011), pp. 043517

Project leadership and contacts /
Projektleitung und Kontakte
Prof. Philippe Jetzer (Project Leader)
Dr. Crescenzo Tortora
Funding source(s) /
Unterstützt durch
SNF (Personen- und Projektförderung)
In collaboration with /
In Zusammenarbeit mit
D. Puy, Universite de Montpellier France
Duration of Project / Projektdauer Jun 2010 to Jun 2012