Science and productivity by Dr. Christine Corbett Moran
As a first step to writing my own simulation code while attempting to do something useful, a few days ago I started writing a code to explore failure and recovery from failure in a distributed computation. By failure in this case, I mean when one of the computation units goes down. My test system is N harmonic oscillators on N nodes (or processes on a shared memory machine). Read More …
A few days ago in gr-qc journal club we discussed an interesting paper by a member of our own institute, Probing the dark matter issue in f(R)-gravity via gravitational lensing.1. Background Dark Matter We theoretically expect dark matter to exist based largely on extensive observations of both dynamics (rotation curves and objects such as the Read More …
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 …
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 …
A few weeks ago, Astrophysics Master’s student Tina Wentz gave a great overview of the phenomenon known as the Pioneer Anomaly in our gr-qc journal club. I’m indebted to her for that overview as well as pointing me to relevant papers in the preparation of this post. Background Launched in 1972 and 1973 respectively, the Read More …
I stated 10 of my principles of teaching stream of consciousness today on twitter while preparing a lecture on Green’s functions. Principle #1: side with your students. Here are the rest…
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 …
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 …
In the morning when I get into lab, around 10 in the morning, I have a set routine. Make a cup of coffee or tea, update my research wiki with a new entry corresponding to the day’s tasks, write/reply to work related emails, admin phygg.com (spam management etc.), scan/vote on papers of interest. Finally I Read More …