Search Results for author: David N. Spergel

Found 32 papers, 24 papers with code

Field-level simulation-based inference with galaxy catalogs: the impact of systematic effects

no code implementations23 Oct 2023 Natalí S. M. de Santi, Francisco Villaescusa-Navarro, L. Raul Abramo, Helen Shao, Lucia A. Perez, Tiago Castro, Yueying Ni, Christopher C. Lovell, Elena Hernandez-Martinez, Federico Marinacci, David N. Spergel, Klaus Dolag, Lars Hernquist, Mark Vogelsberger

In particular, de Santi et al. (2023) developed models that could accurately infer the value of $\Omega_{\rm m}$ from catalogs that only contain the positions and radial velocities of galaxies that are robust to uncertainties in astrophysics and subgrid models.

Simple lessons from complex learning: what a neural network model learns about cosmic structure formation

1 code implementation9 Jun 2022 Drew Jamieson, Yin Li, Siyu He, Francisco Villaescusa-Navarro, Shirley Ho, Renan Alves de Oliveira, David N. Spergel

We find our model generalizes well to these well understood scenarios, demonstrating that the networks have inferred general physical principles and learned the nonlinear mode couplings from the complex, random Gaussian training data.

CoLA

Predicting the Thermal Sunyaev-Zel'dovich Field using Modular and Equivariant Set-Based Neural Networks

1 code implementation28 Feb 2022 Leander Thiele, Miles Cranmer, William Coulton, Shirley Ho, David N. Spergel

We train neural networks on the IllustrisTNG-300 cosmological simulation to predict the continuous electron pressure field in galaxy clusters from gravity-only simulations.

Augmenting astrophysical scaling relations with machine learning: application to reducing the Sunyaev-Zeldovich flux-mass scatter

1 code implementation4 Jan 2022 Digvijay Wadekar, Leander Thiele, Francisco Villaescusa-Navarro, J. Colin Hill, Miles Cranmer, David N. Spergel, Nicholas Battaglia, Daniel Anglés-Alcázar, Lars Hernquist, Shirley Ho

Using SR on the data from the IllustrisTNG hydrodynamical simulation, we find a new proxy for cluster mass which combines $Y_\mathrm{SZ}$ and concentration of ionized gas ($c_\mathrm{gas}$): $M \propto Y_\mathrm{conc}^{3/5} \equiv Y_\mathrm{SZ}^{3/5} (1-A\, c_\mathrm{gas})$.

Symbolic Regression

Inferring halo masses with Graph Neural Networks

1 code implementation16 Nov 2021 Pablo Villanueva-Domingo, Francisco Villaescusa-Navarro, Daniel Anglés-Alcázar, Shy Genel, Federico Marinacci, David N. Spergel, Lars Hernquist, Mark Vogelsberger, Romeel Dave, Desika Narayanan

Furthermore, a GNN trained on a suite of simulations is able to preserve part of its accuracy when tested on simulations run with a different code that utilizes a distinct subgrid physics model, showing the robustness of our method.

Graph Learning

Robust marginalization of baryonic effects for cosmological inference at the field level

no code implementations21 Sep 2021 Francisco Villaescusa-Navarro, Shy Genel, Daniel Angles-Alcazar, David N. Spergel, Yin Li, Benjamin Wandelt, Leander Thiele, Andrina Nicola, Jose Manuel Zorrilla Matilla, Helen Shao, Sultan Hassan, Desika Narayanan, Romeel Dave, Mark Vogelsberger

We train neural networks to perform likelihood-free inference from $(25\, h^{-1}{\rm Mpc})^2$ 2D maps containing the total mass surface density from thousands of hydrodynamic simulations of the CAMELS project.

Multifield Cosmology with Artificial Intelligence

no code implementations20 Sep 2021 Francisco Villaescusa-Navarro, Daniel Anglés-Alcázar, Shy Genel, David N. Spergel, Yin Li, Benjamin Wandelt, Andrina Nicola, Leander Thiele, Sultan Hassan, Jose Manuel Zorrilla Matilla, Desika Narayanan, Romeel Dave, Mark Vogelsberger

Although our maps only cover a small area of $(25~h^{-1}{\rm Mpc})^2$, and the different fields are contaminated by astrophysical effects in very different ways, our networks can infer the values of $\Omega_{\rm m}$ and $\sigma_8$ with a few percent level precision for most of the fields.

Constraining reionization with the first measurement of the cross-correlation between the CMB optical-depth fluctuations and the Compton y-map

no code implementations1 Feb 2021 Toshiya Namikawa, Anirban Roy, Blake D. Sherwin, Nicholas Battaglia, David N. Spergel

Since the power spectrum of the electron density fluctuations is constrained by the $\delta\tau$ auto spectrum, the temperature constraints should be only weakly model-dependent on the details of the electron distributions and should be statistically representative of the temperature in ionized bubbles during reionization.

PICO Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies

A Bayesian neural network predicts the dissolution of compact planetary systems

2 code implementations11 Jan 2021 Miles Cranmer, Daniel Tamayo, Hanno Rein, Peter Battaglia, Samuel Hadden, Philip J. Armitage, Shirley Ho, David N. Spergel

Our model, trained directly from short N-body time series of raw orbital elements, is more than two orders of magnitude more accurate at predicting instability times than analytical estimators, while also reducing the bias of existing machine learning algorithms by nearly a factor of three.

BIG-bench Machine Learning Time Series Analysis

Neural networks as optimal estimators to marginalize over baryonic effects

no code implementations11 Nov 2020 Francisco Villaescusa-Navarro, Benjamin D. Wandelt, Daniel Anglés-Alcázar, Shy Genel, Jose Manuel Zorrilla Mantilla, Shirley Ho, David N. Spergel

For this data, we show that neural networks can 1) extract the maximum available cosmological information, 2) marginalize over baryonic effects, and 3) extract cosmological information that is buried in the regime dominated by baryonic physics.

Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies Instrumentation and Methods for Astrophysics

Teaching neural networks to generate Fast Sunyaev Zel'dovich Maps

no code implementations14 Jul 2020 Leander Thiele, Francisco Villaescusa-Navarro, David N. Spergel, Dylan Nelson, Annalisa Pillepich

The thermal Sunyaev-Zel'dovich (tSZ) and the kinematic Sunyaev-Zel'dovich (kSZ) effects trace the distribution of electron pressure and momentum in the hot Universe.

Cosmology and Nongalactic Astrophysics

What is the price of abandoning dark matter? Cosmological constraints on alternative gravity theories

1 code implementation1 Jul 2020 Kris Pardo, David N. Spergel

Measurements of the large-scale structure of galaxies at low redshift show much weaker features in the spectrum.

Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology

The Effective Halo Model: Creating a Physical and Accurate Model of the Matter Power Spectrum and Cluster Counts

1 code implementation20 Apr 2020 Oliver H. E. Philcox, David N. Spergel, Francisco Villaescusa-Navarro

We introduce a physically-motivated model of the matter power spectrum, based on the halo model and perturbation theory.

Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies Instrumentation and Methods for Astrophysics High Energy Physics - Phenomenology High Energy Physics - Theory

The Quijote simulations

3 code implementations11 Sep 2019 Francisco Villaescusa-Navarro, ChangHoon Hahn, Elena Massara, Arka Banerjee, Ana Maria Delgado, Doogesh Kodi Ramanah, Tom Charnock, Elena Giusarma, Yin Li, Erwan Allys, Antoine Brochard, Chi-Ting Chiang, Siyu He, Alice Pisani, Andrej Obuljen, Yu Feng, Emanuele Castorina, Gabriella Contardo, Christina D. Kreisch, Andrina Nicola, Roman Scoccimarro, Licia Verde, Matteo Viel, Shirley Ho, Stephane Mallat, Benjamin Wandelt, David N. Spergel

The Quijote simulations are a set of 44, 100 full N-body simulations spanning more than 7, 000 cosmological models in the $\{\Omega_{\rm m}, \Omega_{\rm b}, h, n_s, \sigma_8, M_\nu, w \}$ hyperplane.

Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics

Modeling the Gaia Color-Magnitude Diagram with Bayesian Neural Flows to Constrain Distance Estimates

2 code implementations21 Aug 2019 Miles D. Cranmer, Richard Galvez, Lauren Anderson, David N. Spergel, Shirley Ho

We demonstrate an algorithm for learning a flexible color-magnitude diagram from noisy parallax and photometry measurements using a normalizing flow, a deep neural network capable of learning an arbitrary multi-dimensional probability distribution.

Statistical properties of paired fixed fields

1 code implementation5 Jun 2018 Francisco Villaescusa-Navarro, Sigurd Naess, Shy Genel, Andrew Pontzen, Benjamin Wandelt, Lauren Anderson, Andreu Font-Ribera, Nicholas Battaglia, David N. Spergel

We quantify the statistical improvement brought by these simulations, over standard ones, on different power spectra such as matter, halos, CDM, gas, stars, black-holes and magnetic fields, finding that they can reduce their variance by factors as large as $10^6$.

Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics

Weak Lensing of Intensity Mapping: the Cosmic Infrared Background

2 code implementations15 Feb 2018 Emmanuel Schaan, Simone Ferraro, David N. Spergel

To this end, we generalize the CMB lensing quadratic estimator to any weakly non-Gaussian source field, by deriving the optimal lensing weights.

Cosmology and Nongalactic Astrophysics

Looking through the same lens: shear calibration for LSST, Euclid & WFIRST with stage 4 CMB lensing

2 code implementations6 Jul 2016 Emmanuel Schaan, Elisabeth Krause, Tim Eifler, Olivier Doré, Hironao Miyatake, Jason Rhodes, David N. Spergel

We constrain shear calibration biases while simultaneously varying cosmological parameters, galaxy biases and photometric redshift uncertainties.

Cosmology and Nongalactic Astrophysics

Joint likelihood function of cluster counts and $n$-point correlation functions: Improving their power through including halo sample variance

2 code implementations12 Jun 2014 Emmanuel Schaan, Masahiro Takada, David N. Spergel

This approach enables an approximate derivation of a joint likelihood for the cluster number counts, the weak lensing power spectrum and the bispectrum.

Cosmology and Nongalactic Astrophysics

Efficient Power Spectrum Estimation for High Resolution CMB Maps

1 code implementation5 Sep 2008 Sudeep Das, Amir Hajian, David N. Spergel

Estimation of the angular power spectrum of the Cosmic Microwave Background (CMB) on a small patch of sky is usually plagued by serious spectral leakage, specially when the map has a hard edge.

Vocal Bursts Intensity Prediction

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