Theory Seminar

KEK 素粒子原子核研究所・理論セミナー



Correction to the apparent value of the cosmological constant due to local inhomogeneities


(in English)


Dr. Antonio Enea Romano

(National Taiwan University)


August 24 (Wed.) 11:00-12:00


Kenkyu Honkan 3F RM 322  



  Supernovae observations strongly support the presence of a cosmological constant, but its value, which we will call apparent, is normally determined assuming that the Universe can be accurately described by a homogeneous model. Even in the presence of a cosmological constant we cannot exclude nevertheless the presence of a small local inhomogeneity which could affect the apparent value of the cosmological constant. Neglecting the presence of the inhomogeneity can in fact introduce a systematic misinterpretation of cosmological data, leading to the distinction between an apparent and true value of the cosmological constant.  Modeling the local inhomogeneity with a $\Lambda LTB$ solution we compute the relation between the apparent and true value of the cosmological constant. Contrary to previous attempts to fit data using large void models our approach is quite general.  The correction to the apparent value of the cosmological constant is in fact present for local inhomogeneity of any size, and should always be taken appropriately into account both theoretically and observationally.