Publications (80)
Rubin-Euclid Derived Data Products: Initial Recommendations
Leanne P. Guy, Jean-Charles Cuillandre, Etienne Bachelet +117
This report is the result of a joint discussion between the Rubin and Euclid scientific communities. The work presented in this report was focused on designing and recommending an…
Constraining Inverse Curvature Gravity with Supernovae
Olga Mena, Jose Santiago, Jochen Weller
We show that the current accelerated expansion of the Universe can be explained without resorting to dark energy. Models of generalized modified gravity, with inverse powers of the…
Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances and Weak Lensing
DES Collaboration, Tim Abbott, Michel Aguena +129
We perform a joint analysis of the counts and weak lensing signal of redMaPPer clusters selected from the Dark Energy Survey (DES) Year 1 dataset. Our analysis uses the same shear…
Combining cosmological and local bounds on bimetric theory
Angelo Caravano, Marvin Lüben, Jochen Weller
Ghost-free bimetric theory describes two nonlinearly interacting spin-2 fields, one massive and one massless, thus extending general relativity. We confront bimetric theory with ob…
Feature importance for machine learning redshifts applied to SDSS galaxies
Ben Hoyle, Markus Michael Rau, Roman Zitlau +2
We present an analysis of importance feature selection applied to photometric redshift estimation using the machine learning architecture Decision Trees with the ensemble learning…
Precision cosmology with voids in the final BOSS data
Nico Hamaus, Alice Pisani, Jin-Ah Choi +3
We report novel cosmological constraints obtained from cosmic voids in the final BOSS DR12 dataset. They arise from the joint analysis of geometric and dynamic distortions of avera…
On the linearity of tracer bias around voids
Giorgia Pollina, Nico Hamaus, Klaus Dolag +3
The large-scale structure of the universe can only be observed via luminous tracers of the dark matter. However, the clustering statistics of tracers are biased and depend on vario…
Constraining Ultra-light Axions with Galaxy Cluster Number Counts
Johannes Diehl, Jochen Weller
In this paper we investigate the potential of current and upcoming cosmological surveys to constrain the mass and abundance of ultra-light axion (ULA) cosmologies with galaxy clust…
Optimizing the yield of Sunyaev-Zel'dovich cluster surveys
Richard A. Battye, Jochen Weller
We consider the optimum depth of a cluster survey selected using the Sunyaev-Zel'dovich effect. By using simple models for the evolution of the cluster mass function and detailed m…
The Non-Linear Matter Power Spectrum in Warm Dark Matter Cosmologies
Matteo Viel, Katarina Markovic, Marco Baldi +1
We investigate the non-linear evolution of the matter power spectrum by using a large set of high-resolution N-body/hydrodynamic simulations. The linear matter power in the initial…
Neutral hydrogen surveys for high redshift galaxy clusters and proto-clusters
Richard A. Battye, Rod D. Davies, Jochen Weller
We discuss the possibility of performing blind surveys to detect large-scale features of the universe using 21cm emission. Using instruments with approx. 5'-10' resolution currentl…
Reionization by active sources and its effects on the cosmic microwave background
Jochen Weller, Richard A. Battye, Andreas Albrecht
We investigate the possible effects of reionization by active sources on the cosmic microwave background. We concentrate on the sources themselves as the origin of reionization, ra…
Lattice Simulations of Inflation
Angelo Caravano, Eiichiro Komatsu, Kaloian D. Lozanov +1
The scalar field theory of cosmological inflation constitutes nowadays one of the preferred scenarios for the physics of the early universe. In this paper we aim at studying the in…
Joint halo mass function for modified gravity and massive neutrinos I: simulations and cosmological forecasts
Steffen Hagstotz, Matteo Costanzi, Marco Baldi +1
We present a halo mass function accurate over the full relevant Hu-Sawicki parameter space based on spherical collapse calculations and calibrated to a suite of modified gra…
Separate Universes Do Not Constrain Primordial Black Hole Formation
Michael Kopp, Stefan Hofmann, Jochen Weller
Carr and Hawking showed that the proper size of a spherical overdense region surrounded by a flat FRW universe cannot be arbitrarily large as otherwise the region would close up on…
Tuning target selection algorithms to improve galaxy redshift estimates
Ben Hoyle, Kerstin Paech, Markus Michael Rau +2
We showcase machine learning (ML) inspired target selection algorithms to determine which of all potential targets should be selected first for spectroscopic follow up. Efficient t…
Learning Optimal and Interpretable Summary Statistics of Galaxy Catalogs with SBI
Kai Lehman, Sven Krippendorf, Jochen Weller +1
How much cosmological information can we reliably extract from existing and upcoming large-scale structure observations? Many summary statistics fall short in describing the non-Ga…
Why Cosmic Voids Matter: Mitigation of Baryonic Physics
Nico Schuster, Nico Hamaus, Klaus Dolag +1
We utilize the Magneticum suite of state-of-the-art hydrodynamical, as well as dark-matter-only simulations to investigate the effects of baryonic physics on cosmic voids in the hi…
Cosmology with Intensity Mapping via Statistics Beyond the Power Spectrum in the SKAO Era
Suman Majumdar, Debanjan Sarkar, Leon Noble +38
The cosmological distribution of neutral hydrogen (HI) during the post-reionization era is highly non-Gaussian due to the underlying non-linear structure formation, complex galaxy…
Cluster Probes of Dark Energy Clustering
Stephen A. Appleby, Eric V. Linder, Jochen Weller
Cluster abundances are oddly insensitive to canonical early dark energy. Early dark energy with sound speed equal to the speed of light cannot be distinguished from a quintessence…
Dimensional reduction for sampled priors and application to photometric redshift distributions
Gary Bernstein, William Assignies Doumerg, Michael A. Troxel +35
A typical Bayesian inference on the values of some parameters of interest from some data involves running a Markov Chain (MC) to sample from the posterior $p({\bf q},{\…
Probing Modified Gravity by Combining Supernovae and Galaxy Cluster Surveys
Jia-Yu Tang, Jochen Weller, Alan Zablocki
Possible explanations of the observed accelerated expansion of the Universe are the introduction of a dark energy component or the modifications of gravity at large distances. A pa…
Constraining Dark Energy with the Dark Energy Survey: Theoretical Challenges
James Annis, Sarah Bridle, Francisco J. Castander +14
The Dark Energy Survey (DES) will use a new imaging camera on the Blanco 4-m telescope at CTIO to image 5000 square degrees of sky in the South Galactic Cap in four optical bands,…
On the Validity of Cosmological Fisher Matrix Forecasts
Laura Wolz, Martin Kilbinger, Jochen Weller +1
We present a comparison of Fisher matrix forecasts for cosmological probes with Monte Carlo Markov Chain (MCMC) posterior likelihood estimation methods. We analyse the performance…
Improved Primordial Non-Gaussianity Constraints from Measurements of Galaxy Clustering and the Integrated Sachs-Wolfe Effect
Tommaso Giannantonio, Ashley J. Ross, Will J. Percival +5
We present the strongest robust constraints on primordial non-Gaussianity (PNG) from currently available galaxy surveys, combining large-scale clustering measurements and their cro…
Multipole analysis of redshift-space distortions around cosmic voids
Nico Hamaus, Marie-Claude Cousinou, Alice Pisani +3
We perform a comprehensive redshift-space distortion analysis based on cosmic voids in the large-scale distribution of galaxies observed with the Sloan Digital Sky Survey. To this…
Bubbles from dark energy ?
Jochen Weller
In a model recently proposed by Albrecht and Skordis it was suggested that the observed accelerated expansion of the universe could be caused by a scalar field which is trapped in…
Future Supernovae observations as a probe of dark energy
Jochen Weller, Andreas Albrecht
We study the potential impact of improved future supernovae data on our understanding of the dark energy problem. We carefully examine the relative utility of different fitting fun…
Combining clustering and abundances of galaxy clusters to test cosmology and primordial non-Gaussianity
Annalisa Mana, Tommaso Giannantonio, Jochen Weller +3
We present the clustering of galaxy clusters as a useful addition to the common set of cosmological observables. The clustering of clusters probes the large-scale structure of the…
Dark Energy Studies: Challenges to Computational Cosmology
James Annis, Francisco J. Castander, August E. Evrard +12
The ability to test the nature of dark mass-energy components in the universe through large-scale structure studies hinges on accurate predictions of sky survey expectations within…
SOAR/Goodman Spectroscopic Assessment of Candidate Counterparts of the LIGO-Virgo Event GW190814
Douglas Tucker, Matthew Wiesner, Sahar Allam +140
On 2019 August 14 at 21:10:39 UTC, the LIGO/Virgo Collaboration (LVC) detected a possible neutron star-black hole merger (NSBH), the first ever identified. An extensive search for…
Modified Gravity: the CMB, Weak Lensing and General Parameterisations
Shaun A. Thomas, Stephen A. Appleby, Jochen Weller
We examine general physical parameterisations for viable gravitational models in the framework. This is related to the mass of an additional scalar field, called the scalaro…
Opportunities for future supernova studies of cosmic acceleration
Jochen Weller, Andreas Albrecht
We investigate the potential of a future supernova dataset, as might be obtained by the proposed SNAP satellite, to discriminate among different ``dark energy'' theories that descr…
Inhomogeneous reionization and the polarization of the cosmic microwave background
Jochen Weller
In a universe with inhomogeneous reionization, the ionized patches create a second order signal in the cosmic microwave background polarization anisotropy. This signal originates i…
Stacking for machine learning redshifts applied to SDSS galaxies
Roman Zitlau, Ben Hoyle, Kerstin Paech +3
We present an analysis of a general machine learning technique called 'stacking' for the estimation of photometric redshifts. Stacking techniques can feed the photometric redshift…
Constraining warm dark matter with cosmic shear power spectra
Katarina MarkoviÄ, Sarah Bridle, Anže Slosar +1
We investigate potential constraints from cosmic shear on the dark matter particle mass, assuming all dark matter is made up of light thermal relic particles. Given the theoretical…
Constraining Modified Gravity and Growth with Weak Lensing
Shaun A. Thomas, Filipe B. Abdalla, Jochen Weller
The idea that we live in a Universe undergoing a period of acceleration is a strongly held notion in cosmology. As this can, potentially, be explained with a modification to Genera…
Cross-correlation of galaxies and galaxy clusters in the Sloan Digital Sky Survey and the importance of non-Poissonian shot noise
Kerstin Paech, Nico Hamaus, Ben Hoyle +5
We present measurements of angular cross power spectra between galaxies and optically-selected galaxy clusters in the final photometric sample of the Sloan Digital Sky Survey (SDSS…
Constraints on the Primordial Power Spectrum from High Resolution Lyman-alpha Forest Spectra and WMAP
Matteo Viel, Jochen Weller, Martin Haehnelt
The combined analysis of the cosmic microwave background on large scales and Lyman-alpha forest on small scales provides a sufficiently long lever arm to obtain strong constraints…
Fast Identification of Bound Structures in Large N-body Simulations
Jochen Weller, Jeremiah P Ostriker, Paul Bode +1
We present an algorithm which is designed to allow the efficient identification and preliminary dynamical analysis of thousands of structures and substructures in large N-body simu…
Deconstructing Baryon Acoustic Oscillations: A Comparison of Methods
Anais Rassat, Adam Amara, Luca Amendola +6
The Baryon Acoustic Oscillations (BAOs) or baryon wiggles which are present in the galaxy power spectrum at scales 100-150Mpc/h are powerful features with which to constrain cosmol…
Cosmological gravity on all scales V: MCMC forecasts combining large scale structure and CMB lensing for binned phenomenological modified gravity
Sankarshana Srinivasan, Shreya Prabhu, Kai Lehman +2
As cosmology rapidly approaches the data-dominated phase of stage IV large scale structure surveys, the modelling of nonlinear scales has become a serious challenge that faces the…
Dark Energy Survey Year 1 Results: Constraining Baryonic Physics in the Universe
Hung-Jin Huang, Tim Eifler, Rachel Mandelbaum +74
Measurements of large-scale structure are interpreted using theoretical predictions for the matter distribution, including potential impacts of baryonic physics. We constrain the f…
On Model Selection in Cosmology
Martin Kerscher, Jochen Weller
We review some of the common methods for model selection: the goodness of fit, the likelihood ratio test, Bayesian model selection using Bayes factors, and the classical as well as…
The Cosmic Microwave Background and the Ionization History of the Universe
Antony Lewis, Jochen Weller, Richard Battye
Details of how the primordial plasma recombined and how the universe later reionized are currently somewhat uncertain. This uncertainty can restrict the accuracy of cosmological pa…
Overview of 21cm Experiments at high redshift with SKAO
CD Science Working Group, Gianni Bernardi, Daniela Breitman +81
We provide an overview of the eight SKAO Science Book chapters that motivate the Epoch of Reionisation and Cosmic Dawn experiments with SKA-Low. We describe the individual SKA-Low…
Cosmology from the EoR/Cosmic Dawn with the SKA
Jonathan Pritchard, Kiyotomo Ichiki, Andrei Mesinger +8
The SKA will build upon early detections of the EoR by precursor instruments, such as MWA, PAPER, and LOFAR, and planned instruments, such as HERA, to make the first high signal-to…
C3NN-SBI: Learning Hierarchies of -Point Statistics from Cosmological Fields with Physics-Informed Neural Networks
Kai Lehman, Zhengyangguang Gong, David Gebauer +2
Cosmological analyses are moving past the well understood 2-point statistics to extract more information from cosmological fields. A natural step in extending inference pipelines t…
Parameterizing scalar-tensor theories for cosmological probes
Stephen A Appleby, Jochen Weller
We study the evolution of density perturbations for a class of models which closely mimic CDM background cosmology. Using the quasi-static approximation, and the fact th…
Accurate Realizations of the Ionized Gas in Galaxy Clusters: Calibrating Feedback
Paul Bode, Jeremiah P. Ostriker, Jochen Weller +1
Using the full, three-dimensional potential of galaxy cluster halos (drawn from an N-body simulation of the current, most favored cosmology), the distribution of the X-ray emitting…
Why Cosmic Voids Matter: Pristine Evolution
Nico Schuster, Nico Hamaus, Alice Pisani +2
We utilize the Magneticum suite of hydrodynamical simulations to investigate the formation and evolution of cosmic voids from to present day, using cold dark matter and…
Constraining dark sector perturbations II: ISW and CMB lensing tomography
Bjoern Soergel, Tommaso Giannantonio, Jochen Weller +1
Any Dark Energy (DE) or Modified Gravity (MG) model that deviates from a cosmological constant requires a consistent treatment of its perturbations, which can be described in terms…
Particle Physics and Gravitational Waves as complementary windows on the Universe
Steven D. Bass, Laura Baudis, Gianfranco Bertone +16
Particle physics and gravitational waves provide complementary probes of the deep structure of the Universe. Gravitational waves from the mergers of neutron stars and black holes a…
Updated Bounds on Axion-Like Particles from X-ray Observations
Simon Schallmoser, Sven Krippendorf, Francesca Chadha-Day +1
In this work we revisit five different point sources within or behind galaxy clusters in order to constrain the coupling constant between axion-like particles (ALPs) and photons. W…
Sunyaev-Zel'dovich cluster surveys using a large beam
Richard A. Battye, Jochen Weller
Sunyaev Zel'dovich cluster surveys can be used to constrain cosmological parameters. Extracting clusters from the primary anisotropies and the unresolved background from very faint…
On marginals and profiled posteriors for cosmological parameter estimation
Martin Kerscher, Jochen Weller
With several examples and in an analysis of the Pantheon+ supernova sample we discuss the properties of the marginal posterior distribution versus the profiled posterior distributi…
The Imprint of f(R) Gravity on Non-Linear Structure Formation
Ixandra Achitouv, Marco Baldi, Ewald Puchwein +1
We test the imprint of f(R) modified gravity on the halo mass function, using N-body simulations and a theoretical model developed in (Kopp et al. 2013). We find a very good agreem…
Brightest Cluster Galaxy ellipticity as proxy for halo shape: Orientation bias, assembly bias, and potential selection effects in SZ-selected clusters
Radhakrishnan Srinivasan, Tae-hyeon Shin, Anja von der Linden +93
The orientation of triaxial galaxy clusters with respect to the line-of-sight is expected to be one of the prime sources of scatter and potential bias in optical observables (e.g.,…
Lattice simulations of Abelian gauge fields coupled to axions during Inflation
Angelo Caravano, Eiichiro Komatsu, Kaloian D. Lozanov +1
We use a lattice simulation to study a model of axion inflation where the inflaton is coupled to a U(1) gauge field through Chern-Simons interaction. These kinds of models have alr…
Anomaly detection for machine learning redshifts applied to SDSS galaxies
Ben Hoyle, Markus Michael Rau, Kerstin Paech +3
We present an analysis of anomaly detection for machine learning redshift estimation. Anomaly detection allows the removal of poor training examples, which can adversely influence…
Galaxy dispersion measured by Fast Radio Bursts as a probe of baryonic feedback models
Alexander Theis, Steffen Hagstotz, Robert Reischke +1
Fast Radio Bursts (FRBs) are a sensitive probe of the electron distribution in both the large-scale structure and their host galaxies through the dispersion measure (DM) of the rad…
Lattice Simulations of Axion-U(1) Inflation
Angelo Caravano, Eiichiro Komatsu, Kaloian D. Lozanov +1
We present the first nonlinear lattice simulation of an axion field coupled to a U(1) gauge field during inflation. We use it to fully characterize the statistics of the primordial…
Physical parameter space of bimetric theory and SN1a constraints
Marvin Lüben, Angnis Schmidt-May, Jochen Weller
Bimetric theory describes a massless and a massive spin-2 field with fully non-linear (self-)interactions. It has a rich phenomenology and has been successfully tested with several…
Cosmology and Fundamental Physics with the Euclid Satellite
Luca Amendola, Stephen Appleby, Anastasios Avgoustidis +69
Euclid is a European Space Agency medium class mission selected for launch in 2020 within the Cosmic Vision 2015 2025 program. The main goal of Euclid is to understand the origin o…
Complementarity of Future Dark Energy Probes
Jiayu Tang, Filipe B. Abdalla, Jochen Weller
In recent years a plethora of future surveys have been suggested to constrain the nature of dark energy. In this paper we adapt a binning approach to the equation of state factor `…
The Gravitational Lensing Imprints of DES Y3 Superstructures on the CMB: A Matched Filtering Approach
Umut Demirbozan, Seshadri Nadathur, Ismael Ferrero +63
Low density cosmic voids gravitationally lens the cosmic microwave background (CMB), leaving a negative imprint on the CMB convergence . This effect provides insight into th…
Early structure formation with cold plus hot dark matter --- a success of strings plus inflation model
Richard A. Battye, Joao Magueijo, Jochen Weller
Quantum fluctuations created during inflation can account for the observed matter distribution in the linear regime if the universe has two components of dark matter, one which is…
Data augmentation for machine learning redshifts applied to SDSS galaxies
Ben Hoyle, Markus Michael Rau, Christopher Bonnett +2
We present analyses of data augmentation for machine learning redshift estimation. Data augmentation makes a training sample more closely resemble a test sample, if the two base sa…
Constraints on dark matter to dark radiation conversion in the late universe with DES-Y1 and external data
Angela Chen, Dragan Huterer, Sujeong Lee +81
We study a phenomenological class of models where dark matter converts to dark radiation in the low redshift epoch. This class of models, dubbed DMDR, characterizes the evolution o…
Spherical collapse and halo mass function in f(R) theories
Michael Kopp, Stephen A. Appleby, Ixandra Achitouv +1
We compute the critical density of collapse for spherically symmetric overdensities in a class of f(R) modified gravity models. For the first time we evolve the Einstein, scalar fi…
Constraining dark energy with Sunyaev-Zel'dovich cluster surveys
Jochen Weller, Richard Battye, Ruediger Kneissl
We discuss the prospects of constraining the properties of a dark energy component, with particular reference to a time varying equation of state, using future cluster surveys sele…
Constraining cosmological parameters using Sunyaev-Zel'dovich cluster surveys
Richard A. Battye, Jochen Weller
We discuss how future cluster surveys can constrain cosmological parameters with particular reference to the properties of the dark energy component responsible for the observed ac…
Constraints on Cosmology and Gravity from the Dynamics of Voids
Nico Hamaus, Alice Pisani, Paul M. Sutter +4
The Universe is mostly composed of large and relatively empty domains known as cosmic voids, whereas its matter content is predominantly distributed along their boundaries. The rem…
Why Cosmic Voids Matter: Nonlinear Structure & Linear Dynamics
Nico Schuster, Nico Hamaus, Klaus Dolag +1
We use the Magneticum suite of state-of-the-art hydrodynamical simulations to identify cosmic voids based on the watershed technique and investigate their most fundamental properti…
Cosmology and fundamental physics with the Euclid satellite
Luca Amendola, Stephen Appleby, David Bacon +60
Euclid is a European Space Agency medium class mission selected for launch in 2019 within the Cosmic Vision 2015-2025 programme. The main goal of Euclid is to understand the origin…
Modified Gravity and the Flux-weighted Gravity-Luminosity Relationship of Blue Supergiant Stars
Eva Sextl, Rolf-Peter Kudritzki, Jochen Weller +2
We calculate models of stellar evolution for very massive stars and include the effects of modified gravity to investigate the influence on the physical properties of blue supergia…
PICZL: Image-based Photometric Redshifts for AGN
William Roster, Mara Salvato, Sven Krippendorf +14
Computing photo-z for AGN is challenging, primarily due to the interplay of relative emissions associated with the SMBH and its host galaxy. SED fitting methods, effective in penci…
Constraining Dark Energy with X-ray Galaxy Clusters, Supernovae and the Cosmic Microwave Background
David Rapetti, Steven W. Allen, Jochen Weller
We present new constraints on the evolution of dark energy from an analysis of Cosmic Microwave Background, supernova and X-ray galaxy cluster data. Our analysis employs a minimum…
The bias of cosmic voids in the presence of massive neutrinos
Nico Schuster, Nico Hamaus, Alice Pisani +4
Cosmic voids offer an extraordinary opportunity to study the effects of massive neutrinos on cosmological scales. Because they are freely streaming, neutrinos can penetrate the int…
The eROSITA Final Equatorial-Depth Survey (eFEDS): A Machine Learning Approach to Infer Galaxy Cluster Masses from eROSITA X-ray Images
Sven Krippendorf, Nicolas Baron Perez, Esra Bulbul +15
We develop a neural network based pipeline to estimate masses of galaxy clusters with a known redshift directly from photon information in X-rays. Our neural networks are trained u…