People

Kazuyuki Akitsu
Position
Todai Postdoctoral Research Fellow (from 2020/04/01 ) [JSPS Fellow]
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Research Field
Theoretical Physics (Cosmology)
E-Mail
<kazuyuki.akitsu _at_ ipmu.jp> 
PHOTO

Last Update 2020/07/06

My research interest lies in several aspects of "non-"xxx in cosmology, such as non-linear evolution driven by gravity, non-Gaussianity in the primordial perturbations, and anisotropic signals in cosmological observables. (/p)

I have been working on the so-called "super-sample effect", especially its tidal effect. Since we can observe only finite region in any surveys, we cannot measure longer-wavelength fluctuations than a finite-volume directly. Due to the nature of gravity, however, these long-wavelength modes (called "super-sample modes") affect short-wavelength fluctuations via the non-linear mode-coupling. In particular, I revealed that the super-sample modes leave anisotropic imprints in the galaxy clustering. This effect introduces additional covariance in the data but this is also a new signal in itself; that is, we can infer the longest-wavelength fluctuation in our universe by deciphering the imprints of the super-sample modes in short-wavelength observables. I have developed a method to do so and recently also started to study the impact of the anisotropic primordial non-Gaussianity on observed galaxy shapes.

The goal of my research is to gain insight into fundamental physics and cosmology using the large-scale structure and the cosmic microwave background by combining these studies.


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