no code implementations • 22 Nov 2022 • Sotiris Anagnostidis, Arne Thomsen, Tomasz Kacprzak, Tilman Tröster, Luca Biggio, Alexandre Refregier, Thomas Hofmann
In this work, we aim to improve upon two-point statistics by employing a \textit{PointNet}-like neural network to regress the values of the cosmological parameters directly from point cloud data.
1 code implementation • 17 Mar 2022 • Tomasz Kacprzak, Janis Fluri
Galaxy bias $b_g$ is improved by 1. 5x, stochasticity $r_g$ by 3x, and the redshift evolution $\eta_{\rm{IA}}$ and $\eta_b$ by 1. 6x.
no code implementations • 17 Apr 2020 • Nathanaël Perraudin, Sandro Marcon, Aurelien Lucchi, Tomasz Kacprzak
Weak gravitational lensing mass maps play a crucial role in understanding the evolution of structures in the universe and our ability to constrain cosmological models.
1 code implementation • 15 Aug 2019 • Nathanaël Perraudin, Ankit Srivastava, Aurelien Lucchi, Tomasz Kacprzak, Thomas Hofmann, Alexandre Réfrégier
Our results show that the proposed model produces samples of high visual quality, although the statistical analysis reveals that capturing rare features in the data poses significant problems for the generative models.
no code implementations • 7 Jun 2019 • Janis Fluri, Tomasz Kacprzak, Aurelien Lucchi, Alexandre Refregier, Adam Amara, Thomas Hofmann, Aurel Schneider
We present the cosmological results with a CNN from the KiDS-450 tomographic weak lensing dataset, constraining the total matter density $\Omega_m$, the fluctuation amplitude $\sigma_8$, and the intrinsic alignment amplitude $A_{\rm{IA}}$.
Cosmology and Nongalactic Astrophysics
7 code implementations • 8 Apr 2019 • Michaël Defferrard, Nathanaël Perraudin, Tomasz Kacprzak, Raphael Sgier
Spherical data is found in many applications.
6 code implementations • 29 Oct 2018 • Nathanaël Perraudin, Michaël Defferrard, Tomasz Kacprzak, Raphael Sgier
We present a spherical CNN for analysis of full and partial HEALPix maps, which we call DeepSphere.
no code implementations • 23 Jul 2018 • Janis Fluri, Tomasz Kacprzak, Aurelien Lucchi, Alexandre Refregier, Adam Amara, Thomas Hofmann
We find that, for a shape noise level corresponding to 8. 53 galaxies/arcmin$^2$ and the smoothing scale of $\sigma_s = 2. 34$ arcmin, the network is able to generate 45% tighter constraints.
Cosmology and Nongalactic Astrophysics
no code implementations • 27 Jan 2018 • Andres C. Rodriguez, Tomasz Kacprzak, Aurelien Lucchi, Adam Amara, Raphael Sgier, Janis Fluri, Thomas Hofmann, Alexandre Réfrégier
Computational models of the underlying physical processes, such as classical N-body simulations, are extremely resource intensive, as they track the action of gravity in an expanding universe using billions of particles as tracers of the cosmic matter distribution.
no code implementations • 23 Jan 2018 • Jörg Herbel, Tomasz Kacprzak, Adam Amara, Alexandre Refregier, Aurelien Lucchi
We find that our approach is able to accurately reproduce the SDSS PSF at the pixel level, which, due to the speed of both the model evaluation and the parameter estimation, offers good prospects for incorporating our method into the $MCCL$ framework.
no code implementations • 24 Jul 2017 • Tomasz Kacprzak, Jörg Herbel, Adam Amara, Alexandre Réfrégier
This model is trained on a small number of simulations and estimates which regions of the prior space are likely to be accepted into the posterior.
no code implementations • 17 Jul 2017 • Jorit Schmelzle, Aurelien Lucchi, Tomasz Kacprzak, Adam Amara, Raphael Sgier, Alexandre Réfrégier, Thomas Hofmann
We find that our implementation of DCNN outperforms the skewness and kurtosis statistics, especially for high noise levels.
1 code implementation • 29 Jul 2014 • Barnaby Rowe, Mike Jarvis, Rachel Mandelbaum, Gary M. Bernstein, James Bosch, Melanie Simet, Joshua E. Meyers, Tomasz Kacprzak, Reiko Nakajima, Joe Zuntz, Hironao Miyatake, Joerg P. Dietrich, Robert Armstrong, Peter Melchior, Mandeep S. S. Gill
GALSIM is a collaborative, open-source project aimed at providing an image simulation tool of enduring benefit to the astronomical community.
Instrumentation and Methods for Astrophysics Cosmology and Nongalactic Astrophysics 85-04