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We introduce a sub-grid model for the non-equilibrium abundance of molecular hydrogen in cosmological simulations of galaxy formation. We improve upon previous work by accounting for the unresolved structure of molecular clouds in a…

Astrophysics of Galaxies · Physics 2015-06-19 Matteo Tomassetti , Cristiano Porciani , Emilio Romano-Diaz , Aaron D. Ludlow

We present a comparison of nine galaxy formation models, eight semi-analytical and one halo occupation distribution model, run on the same underlying cold dark matter simulation (cosmological box of co-moving width 125$h^{-1}$ Mpc, with a…

Various galaxy merger detection methods have been applied to diverse datasets. However, it is difficult to understand how they compare. We aim to benchmark the relative performance of machine learning (ML) merger detection methods. We…

Understanding the halo-galaxy connection is fundamental in order to improve our knowledge on the nature and properties of dark matter. In this work we build a model that infers the mass of a halo given the positions, velocities, stellar…

We develop a machine learning algorithm that generates high-resolution thermal Sunyaev-Zeldovich (SZ) maps of novel galaxy clusters given only halo mass and mass accretion rate. The algorithm uses a conditional variational autoencoder…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-23 Tibor Rothschild , Daisuke Nagai , Han Aung , Sheridan B. Green , Michelle Ntampaka , John ZuHone

This paper describes the open-source code Enzo, which uses block-structured adaptive mesh refinement to provide high spatial and temporal resolution for modeling astrophysical fluid flows. The code is Cartesian, can be run in 1, 2, and 3…

Semi-analytic models are a powerful tool for studying the formation of galaxies. However, these models inevitably involve a significant number of poorly constrained parameters that must be adjusted to provide an acceptable match to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 R. G. Bower , I. Vernon , M. Goldstein , A. J. Benson , C. G. Lacey , C. M. Baugh , S. Cole , C. S. Frenk , .

Current Adaptive Mesh Refinement (AMR) simulations require algorithms that are highly parallelized and manage memory efficiently. As compute engines grow larger, AMR simulations will require algorithms that achieve new levels of efficient…

Solar and Stellar Astrophysics · Physics 2015-03-19 Jonathan J. Carroll-Nellenback , Brandon Shroyer , Adam Frank , Chen Ding

In order to better understand the relationship between feedback and galactic chemical evolution, we have developed a new model for stellar feedback at grid resolutions of only a few parsecs in global disk simulations, using the adaptive…

Astrophysics of Galaxies · Physics 2018-10-17 Andrew Emerick , Greg L. Bryan , Mordecai-Mark Mac Low

In this fourth paper from the AGORA Collaboration, we study the evolution down to redshift $z=2$ and below of a set of cosmological zoom-in simulations of a Milky Way mass galaxy by eight of the leading hydrodynamic simulation codes. We…

Reliable extraction of cosmological information from clustering measurements of galaxy surveys requires estimation of the error covariance matrices of observables. The accuracy of covariance matrices is limited by our ability to generate…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-29 Mohammadjavad Vakili , Francisco-Shu Kitaura , Yu Feng , Gustavo Yepes , Cheng Zhao , Chia-Hsun Chuang , ChangHoon Hahn

Model calibration consists of using experimental or field data to estimate the unknown parameters of a mathematical model. The presence of model discrepancy and measurement bias in the data complicates this task. Satellite interferograms,…

Methodology · Statistics 2023-02-28 Mengyang Gu , Kyle Anderson , Erika McPhillips

Context. Synthetic model atmosphere calculations are still the most commonly used tool when determining precise stellar parameters and stellar chemical compositions. Besides three-dimensional models that consistently solve for hydrodynamic…

Solar and Stellar Astrophysics · Physics 2015-05-20 X. S. Wu , S. Alexeeva , L. Mashonkina , L. Wang , G. Zhao , F. Grupp

We introduce a new method to calculate dark matter halo density profiles from simulations. Each particle is 'smeared' over its orbit to obtain a dynamical profile that is averaged over a dynamical time, in contrast to the traditional…

Astrophysics of Galaxies · Physics 2024-01-26 Claudia Muni , Andrew Pontzen , Jason L. Sanders , Martin P. Rey , Justin I. Read , Oscar Agertz

Next-generation surveys will provide photometric and spectroscopic data of millions to billions of galaxies with unprecedented precision. This offers a unique chance to improve our understanding of the galaxy evolution and the unresolved…

Strategies to model the inspiral, merger and ringdown gravitational waveform of coalescing binaries are restricted in parameter space by the coverage of available numerical-relativity simulations. When more numerical waveforms become…

General Relativity and Quantum Cosmology · Physics 2019-01-10 Yoshinta Eka Setyawati , Frank Ohme , Sebastian Khan

We present morphological classifications obtained using machine learning for objects in SDSS DR6 that have been classified by Galaxy Zoo into three classes, namely early types, spirals and point sources/artifacts. An artificial neural…

In the context of computer models, calibration is the process of estimating unknown simulator parameters from observational data. Calibration is variously referred to as model fitting, parameter estimation/inference, an inverse problem, and…

Methodology · Statistics 2023-10-16 Richard D. Wilkinson , Christopher W. Lanyon

For an autonomous vehicle, the ability to sense its surroundings and to build an overall representation of the environment by fusing different sensor data streams is fundamental. To this end, the poses of all sensors need to be accurately…

Robotics · Computer Science 2022-11-07 Brahayam Ponton , Magda Ferri , Lars Koenig , Marcus Bartels

Machine learning (ML) methods have become popular for parameter inference in cosmology, although their reliance on specific training data can cause difficulties when applied across different data sets. By reproducing and testing networks…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-23 Kimeel Sooknunan , Emma Chapman , Luke Conaboy , Daniel Mortlock , Jonathan Pritchard