Search Results for author: Benjamin Joachimi

Found 9 papers, 6 papers with code

Magnification bias in galaxy surveys with complex sample selection functions

1 code implementation13 Jan 2021 Maximilian von Wietersheim-Kramsta, Benjamin Joachimi, Jan Luca van den Busch, Catherine Heymans, Hendrik Hildebrandt, Marika Asgari, Tilman Tröster, Angus H. Wright

For BOSS-like lenses, we forecast a contribution of the magnification bias to the GGL signal between the multipole moments, $\ell$, of 100 and 4600 with a cumulative signal-to-noise ratio between 0. 1 and 1. 1 for sources from the Kilo-Degree Survey (KiDS), between 0. 4 and 2. 0 for sources from the Hyper Suprime-Cam survey (HSC), and between 0. 3 and 2. 8 for ESA Euclid-like source samples.

Cosmology and Nongalactic Astrophysics

Towards fast machine-learning-assisted Bayesian posterior inference of realistic microseismic events

1 code implementation12 Jan 2021 Davide Piras, Alessio Spurio Mancini, Benjamin Joachimi, Michael P. Hobson

We train a machine learning algorithm on the power spectrum of the recorded pressure wave and show that the trained emulator allows for the complete and fast retrieval of the event coordinates for $\textit{any}$ source mechanism.

Bayesian Inference

Organised Randoms: Learning and correcting for systematic galaxy clustering patterns in KiDS using self-organising maps

no code implementations15 Dec 2020 Harry Johnston, Angus H. Wright, Benjamin Joachimi, Maciej Bilicki, Nora Elisa Chisari, Andrej Dvornik, Thomas Erben, Benjamin Giblin, Catherine Heymans, Hendrik Hildebrandt, Henk Hoekstra, Shahab Joudaki, Mohammadjavad Vakili

We then create `organised' randoms, i. e. random galaxy catalogues with spatially variable number densities, mimicking the learnt systematic density modes in the data.

Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies

KiDS+VIKING-450: Improved cosmological parameter constraints from redshift calibration with self-organising maps

no code implementations8 May 2020 Angus H. Wright, Hendrik Hildebrandt, Jan Luca van den Busch, Catherine Heymans, Benjamin Joachimi, Arun Kannawadi, Konrad Kuijken

We present updated cosmological constraints for the KiDS+VIKING-450 cosmic shear dataset (KV450), estimated using redshift distributions and photometric samples defined using self organising maps (SOMs).

Cosmology and Nongalactic Astrophysics

The halo model as a versatile tool to predict intrinsic alignments

no code implementations5 Mar 2020 Maria Cristina Fortuna, Henk Hoekstra, Benjamin Joachimi, Harry Johnston, Nora Elisa Chisari, Christos Georgiou, Constance Mahony

In this paper, we use the halo model formalism to capture this diversity and examine its implications for Stage-III and Stage-IV cosmic shear surveys.

Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies

GEOMAX: beyond linear compression for 3pt galaxy clustering statistics

1 code implementation2 Dec 2019 Davide Gualdi, Héctor Gil-Marín, Marc Manera, Benjamin Joachimi, Ofer Lahav

By applying GEOMAX to bispectrum monopole measurements from BOSS DR12 CMASS redshift-space galaxy clustering data, we reduce the $68\%$ credible intervals for the inferred parameters $\left(b_1, b_2, f,\sigma_8\right)$ by $\left(50. 4\%, 56. 1\%, 33. 2\%, 38. 3\%\right)$ with respect to standard MCMC on the full data vector.

Cosmology and Nongalactic Astrophysics

Geometrical compression: a new method to enhance the BOSS galaxy bispectrum monopole constraints

1 code implementation4 Jan 2019 Davide Gualdi, Héctor Gil-Marín, Marc Manera, Benjamin Joachimi, Ofer Lahav

We present a novel method to compress galaxy clustering three-point statistics and apply it to redshift space galaxy bispectrum monopole measurements from BOSS DR12 CMASS data considering a $k$-space range of $0. 03-0. 12\, h/\mathrm{Mpc}$.

Cosmology and Nongalactic Astrophysics

CFHTLenS revisited: assessing concordance with Planck including astrophysical systematics

1 code implementation21 Jan 2016 Shahab Joudaki, Chris Blake, Catherine Heymans, Ami Choi, Joachim Harnois-Deraps, Hendrik Hildebrandt, Benjamin Joachimi, Andrew Johnson, Alexander Mead, David Parkinson, Massimo Viola, Ludovic van Waerbeke

When the systematic uncertainties are considered independently, the intrinsic alignment amplitude is the only degree of freedom that is substantially preferred by the data.

Cosmology and Nongalactic Astrophysics

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