06-04-07

As part of the final for the PHYS 437B research course I have completed a poster summarizing my scientific work for the two terms and the conclusions reached.

16-03-07

Finally, tracked halos!

After a long cycle of design, code, and testing (not to mention a bit of debugging ;) ) I finally have a halo tracker. I'm pleased and confident with the preliminary results and analysis, which suggests robust halo tracking. The next step is application to a higher resolution cluster of scientific value. AMIGA Halo Finder (AHF) is used to build a cluster catalog for each simulation output and then my halo tracker is used to match progenitors to descendants. I've attached a graphical rendering of a subset of data below with a description.

The plot above shows satellite halo distance from cluster center over the red shift range z=1 to z=0. The time resolution of the outputs is ~0.01a (~137million years) between snapshots.

Each black line represents a halo's cluster centric distance at that time. The red line shows the time evolution of the virial radius of the cluster. Orbits are clearly shown. One halo is seen to already be orbiting the cluster at z=1 and does so at least 3 or more times. Radially infalling halos are seen as >= 45 degree lines. Halos approaching the cluster with a tangential component have a shallower slope. It appears that there are no subhalos with circular orbits. Also, you can see that AHF looses most halos that approach within 1/2 of the virial radius, Rvir.

Recovery of lost halos by the tracker is seen in the straight-line breaks in the otherwise smooth orbits. Reduced density contrast between the cluster substructure and it's core is likly responsable. Once AHF is able to "see" the initially lost subhalo again, the halo tracker repairs the broken progenitor-descendant chain.

09-11-06

Here are a couple of interesting papers I stumbled upon...
Cosmic stellar relics in the Galactic halo
The first generation of stars in LCDM cosmology

Also, for anyone interested, my work has not become stagnant even though my website has :)

24-08-06

I have just posted my contact information on the About Me page.

21-08-06

Scientists have discovered the best indirect evidence yet of the existance of dark matter in a galaxy cluster collision. You can find a news brief here at Space.com.

I have also just posted a skeleton about me page. It is currently very brief but it will be expanded on in the future.

18-08-06

I have just posted the first tool of a series on the software page. tpm2gadget quite simply translates a set of TPM files into a single gadget file. The whole translation is simply, x_gadget = x_TPM*Mpc/LenUnit*h and v_gadget = v_peculiar_TPM/sqrt(a). Where a=1/(z+1) and LenUnit is specified as 1kpc(cm) in common.h but it is more or less arbatrary.

Don't expect any thing else too quickly though. I'm still in the middle of writing and testing everything and I'm thinking that it will be about 8 months(I hope :) ) before I'm done.

Anyway, on to something more interesting. Below is a projection of particles in the x-y plane of a slice(L/2) of a 100Mpc/h cosmological dark matter box (Ohm_b=.044, Ohm_m=.27, h=.71) at z=0 simulated by Gadget-2. The initial conditions were generated with a combination of CMBFAST and Edwin Sirko's ic. The TPM files were converted with tpm2gadget.

17-08-06

Welcome. I have been planning on creating a webpage for a good while now but I had just not gotten around to it until now. The reason has been my physics project keeping me busy. Not to mention that it is too interesting for me to put it down for any significant length of time.

Anyway, down to business.

Here I will post information as well as any software that I have found particularly useful to my endeavors. You can learn about my current work in the Work page as well as a small personal background on the About Me page I will also post links to pages that have been especially useful to me or that I enjoy.

Forgive me for the rather boring look as I put this all together in about ½ hour. Oh and one last thing, not all of the page references on the navigation bar are working. At least until I get the time to finish everything.