Search Results for author: Kazuya Koyama

Found 7 papers, 6 papers with code

The clustering of the SDSS-IV extended Baryon Oscillation Spectroscopic Survey DR16 luminous red galaxy and emission line galaxy samples: cosmic distance and structure growth measurements using multiple tracers in configuration space

1 code implementation17 Jul 2020 Yuting Wang, Gong-Bo Zhao, Cheng Zhao, Oliver H. E. Philcox, Shadab Alam, Amélie Tamone, Arnaud de Mattia, Ashley J. Ross, Anand Raichoor, Etienne Burtin, Romain Paviot, Sylvain de la Torre, Will J. Percival, Kyle S. Dawson, Héctor Gil-Marín, Julian E. Bautista, Jiamin Hou, Kazuya Koyama, John A. Peacock, Vanina Ruhlmann-Kleider, Hélion du Mas des Bourboux, Johan Comparat, Stephanie Escoffier, Eva-Maria Mueller, Jeffrey A. Newman, Graziano Rossi, Arman Shafieloo, Donald P. Schneider

We perform a multi-tracer analysis using the complete Sloan Digital Sky Survey IV (SDSS-IV) extended Baryon Oscillation Spectroscopic Survey (eBOSS) DR16 luminous red galaxy (LRG) and the DR16 emission line galaxy (ELG) samples in the configuration space, and successfully detect a cross correlation between the two samples, and find the growth rate to be $f\sigma_8=0. 342 \pm 0. 085$ ($\sim25$ per cent accuracy) from the cross sample alone.

Cosmology and Nongalactic Astrophysics

Investigating Cosmological GAN Emulators Using Latent Space Interpolation

1 code implementation21 Apr 2020 Andrius Tamosiunas, Hans A. Winther, Kazuya Koyama, David J. Bacon, Robert C. Nichol, Ben Mawdsley

Recent results show that GANs can be used as a fast, efficient and computationally cheap emulator for producing novel weak lensing convergence maps as well as cosmic web data in 2-D and 3-D.

Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics Computational Physics

COLA with scale-dependent growth: applications to screened modified gravity models

1 code implementation2 Mar 2017 Hans A. Winther, Kazuya Koyama, Marc Manera, Bill S. Wright, Gong-Bo Zhao

We present a general parallelized and easy-to-use code to perform numerical simulations of structure formation using the COLA (COmoving Lagrangian Acceleration) method for cosmological models that exhibit scale-dependent growth at the level of first and second order Lagrangian perturbation theory.

Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology

Impact of polarisation on the intrinsic CMB bispectrum

1 code implementation11 Jun 2014 Guido W. Pettinari, Christian Fidler, Robert Crittenden, Kazuya Koyama, Antony Lewis, David Wands

We find that the presence of the intrinsic bispectrum will bias a measurement of primordial non-Gaussianity of local type by $f_{NL}^\text{bias}=0. 66$ for an ideal experiment with $\ell_\text{max}=3000$.

Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology

The intrinsic B-mode polarisation of the Cosmic Microwave Background

no code implementations14 Jan 2014 Christian Fidler, Guido W. Pettinari, Martin Beneke, Robert Crittenden, Kazuya Koyama, David Wands

The intrinsic B-mode polarisation is present independent of the initial conditions and might contaminate the signal from primordial gravitational waves.

Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology

The intrinsic bispectrum of the Cosmic Microwave Background

1 code implementation4 Feb 2013 Guido W. Pettinari, Christian Fidler, Robert Crittenden, Kazuya Koyama, David Wands

We develop a new, efficient code for solving the second-order Einstein-Boltzmann equations, and use it to estimate the intrinsic CMB non-Gaussianity arising from the non-linear evolution of density perturbations.

Cosmology and Nongalactic Astrophysics High Energy Physics - Theory

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