Category: physics

Halos gone MAD

Posted onAuthorChristine Corbett MoranLeave a comment

I have previously blogged about Structure finding in cosmological simulations and the Haloes Going Mad conference in Madrid this past spring–there you will find the basic background if you are unfamiliar with the subject and I’ll skip that in this post. The result of this conference was a Halo-finder comparison project and its findings were recent posted on the physics arxiv in the paper Haloes gone MAD: The Halo-Finder Comparison Project. I’ll summarize them here.

The paper concentrates on comparing codes on given test data, not comparing the results of various codes to observations, provides a standard test suite and proposes a standard methodology of comparison, both on test, isolated, halos and on a simulation of cosmological volume. Read More …

Geometry and Dynamics of the Cosmic Web

Locally Cold Flows from Large-Scale Structure

Posted onAuthorChristine Corbett MoranLeave a comment

Walls, filaments and voids: it is thought that the large scale distribution of matter is a complex network of galaxies and galaxy clusters connected by elongated filaments and sheetlike walls, outlining vast underdense regions known as voids and meeting at dense and compact regions known as haloes. Aragon-Calvo et. al. in [1] build upon the SpineWeb framework outlined in [2] , which has the capability of identifying these walls, filaments and clusters in cosmological simulations to examine the effect of environment (namely whether a galaxy is “living” in a wall or a void) on the dispersion of the Hubble flow around the Milky, which is significantly lower than theoretical expectations. They show that the measured dispersion could be a result of the fact that Milky Way resides inside a wall of radius around 10Mpc, which is supported by data. Read More …

Andromeda Galaxy

The Andromeda Galaxy's Globular Cluster System

Posted onAuthorChristine Corbett MoranLeave a comment

Globular Clusters (GCs) Globular clusters are groups of roughly spherical, densely packed stars. They are thought to have formed at the same time as most galaxies and the stars which make them up are some of the oldest known–thus GCs are an excellent probe of galaxy formation and evolution. They have a high central stellar Read More …

Classification of Lie Groups

Quantum Field Theory (QFT), General Relativity (GR), and Other Exciting Diversions (OED)

Posted onAuthorChristine Corbett MoranLeave a comment

QFT I’m lucky to have a job in which I can take two weeks of mornings of work to study a nominally tangential subject in greater depth. These past two weeks I attended a series of  lectures at the ETH on physics beyond the standard model, the first week was very technical but exciting to Read More …