Search Results for author: Risa H. Wechsler

Found 17 papers, 12 papers with code

Insights into the origin of halo mass profiles from machine learning

no code implementations9 May 2022 Luisa Lucie-Smith, Susmita Adhikari, Risa H. Wechsler

We find two primary scales in the initial conditions (ICs) that impact the final mass profile: the density at approximately the scale of the haloes' Lagrangian patch $R_L$ ($R\sim 0. 7\, R_L$) and that in the large-scale environment ($R\sim 1. 7~R_L$).

BIG-bench Machine Learning Interpretable Machine Learning

Hierarchical Inference With Bayesian Neural Networks: An Application to Strong Gravitational Lensing

1 code implementation26 Oct 2020 Sebastian Wagner-Carena, Ji Won Park, Simon Birrer, Philip J. Marshall, Aaron Roodman, Risa H. Wechsler

We show that the posterior PDFs are sufficiently accurate (i. e., statistically consistent with the truth) across a wide variety of power-law elliptical lens mass distributions.

Constraints on Dark Matter Microphysics from the Milky Way Satellite Population

1 code implementation22 Apr 2019 Ethan O. Nadler, Vera Gluscevic, Kimberly K. Boddy, Risa H. Wechsler

Alternatives to the cold, collisionless dark matter (DM) paradigm in which DM behaves as a collisional fluid generically suppress small-scale structure.

Cosmology and Nongalactic Astrophysics High Energy Physics - Phenomenology

Modeling the Connection Between Subhalos and Satellites in Milky Way-Like Systems

1 code implementation14 Sep 2018 Ethan O. Nadler, Yao-Yuan Mao, Gregory M. Green, Risa H. Wechsler

We develop a comprehensive and flexible model for the connection between satellite galaxies and dark matter subhalos in dark matter-only zoom-in simulations of Milky Way (MW)-mass host halos.

Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics

Analyzing interferometric observations of strong gravitational lenses with recurrent and convolutional neural networks

no code implementations31 Jul 2018 Warren R. Morningstar, Yashar D. Hezaveh, Laurence Perreault Levasseur, Roger D. Blandford, Philip J. Marshall, Patrick Putzky, Risa H. Wechsler

We use convolutional neural networks (CNNs) and recurrent neural networks (RNNs) to estimate the parameters of strong gravitational lenses from interferometric observations.

Instrumentation and Methods for Astrophysics

The Aemulus Project I: Numerical Simulations for Precision Cosmology

no code implementations16 Apr 2018 Joseph DeRose, Risa H. Wechsler, Jeremy L. Tinker, Matthew R. Becker, Yao-Yuan Mao, Thomas McClintock, Sean McLaughlin, Eduardo Rozo, Zhongxu Zhai

We show that these statistics are converged to 1% (2%) for halos with more than 500 (200) particles respectively and scales of r>200 ~ h^-1 kpc in real space or k ~ 3 h Mpc^-1 in harmonic space for z\le 1.

Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies

Modeling the Impact of Baryons on Subhalo Populations with Machine Learning

1 code implementation12 Dec 2017 Ethan O. Nadler, Yao-Yuan Mao, Risa H. Wechsler, Shea Garrison-Kimmel, Andrew Wetzel

We identify subhalos in dark matter-only (DMO) zoom-in simulations that are likely to be disrupted due to baryonic effects by using a random forest classifier trained on two hydrodynamic simulations of Milky Way (MW)-mass host halos from the Latte suite of the Feedback in Realistic Environments (FIRE) project.

Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics

Mapping Extragalactic Dark Matter Annihilation with Galaxy Surveys: A Systematic Study of Stacked Group Searches

no code implementations1 Sep 2017 Mariangela Lisanti, Siddharth Mishra-Sharma, Nicholas L. Rodd, Benjamin R. Safdi, Risa H. Wechsler

Applying this procedure to a catalog of sources, one can create a full-sky map of the brightest extragalactic dark matter targets in the nearby Universe ($z\lesssim 0. 03$), supplementing sources of dark matter annihilation from within the Local Group.

Cosmology and Nongalactic Astrophysics High Energy Astrophysical Phenomena High Energy Physics - Phenomenology

Uncertainties in Parameters Estimated with Neural Networks: Application to Strong Gravitational Lensing

no code implementations29 Aug 2017 Laurence Perreault Levasseur, Yashar D. Hezaveh, Risa H. Wechsler

In Hezaveh et al. 2017 we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational lensing systems.

Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics

Biased Tracers in Redshift Space in the EFT of Large-Scale Structure

2 code implementations28 Oct 2016 Ashley Perko, Leonardo Senatore, Elise Jennings, Risa H. Wechsler

The Effective Field Theory of Large-Scale Structure (EFTofLSS) provides a novel formalism that is able to accurately predict the clustering of large-scale structure (LSS) in the mildly non-linear regime.

Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology High Energy Physics - Theory

Connecting CO Intensity Mapping to Molecular Gas and Star Formation in the Epoch of Galaxy Assembly

1 code implementation30 Mar 2015 Tony Y. Li, Risa H. Wechsler, Kiruthika Devaraj, Sarah E. Church

Here we present predictions for the intensity map and power spectrum of the CO(1-0) line from galaxies at z ~ 2. 4 -2. 8, based on a parameterized model for the galaxy-halo connection, and demonstrate the extent to which properties of high-redshift galaxies can be directly inferred from such observations.

Cosmology and Nongalactic Astrophysics Astrophysics of Galaxies

Gravitationally Consistent Halo Catalogs and Merger Trees for Precision Cosmology

1 code implementation19 Oct 2011 Peter S. Behroozi, Risa H. Wechsler, Hao-Yi Wu, Michael T. Busha, Anatoly A. Klypin, Joel R. Primack

We find that both the ROCKSTAR and BDM halo finders track halos extremely well; in both, the number of halos which do not have physically consistent progenitors is at the 1-2% level across all halo masses.

Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics

The Rockstar Phase-Space Temporal Halo Finder and the Velocity Offsets of Cluster Cores

4 code implementations19 Oct 2011 Peter S. Behroozi, Risa H. Wechsler, Hao-Yi Wu

We present a new algorithm for identifying dark matter halos, substructure, and tidal features.

Cosmology and Nongalactic Astrophysics Instrumentation and Methods for Astrophysics

ArborZ: Photometric Redshifts Using Boosted Decision Trees

1 code implementation27 Aug 2009 David W. Gerdes, Adam J. Sypniewski, Timothy A. McKay, Jiangang Hao, Matthew R. Weis, Risa H. Wechsler, Michael T. Busha

Precision photometric redshifts will be essential for extracting cosmological parameters from the next generation of wide-area imaging surveys.

Cosmology and Nongalactic Astrophysics

Cannot find the paper you are looking for? You can Submit a new open access paper.