Tag Archives: viz

Optimized Multi-Frequency Spectra

Last week, we submitted a paper titled “Optimized Multi-Frequency Spectra for Applications in Radiative Feedback and Cosmological Reionization” to the Astrophysical Journal.  You can find it on arXiv.  Here we investigate the impact of varying energy discretizations in radiation transport schemes.  Mono-chromatic approximations can underestimate the amount of partial ionization at large radii because all of the ionizing photons are absorbed at some characteristic radius.  This is especially true for X-rays, which have large mean free paths.

With a multi-frequency approach, the solution converges with 4 or more frequency bins. For example with a 10^5 K blackbody source, the temperature of an HII region at r = 8 kpc is underestimated by a factor of 20 if a mono-chromatic spectrum is used.  However it is unclear the best technique on how to choose these frequencies.  In this work, we developed a Monte Carlo scheme to determine optimal frequency values for such radiation calculations.  In the paper, we give optimal discretizations for a 10^5 K blackbody and power law spectrum for 1-4 bins.  The code that employs this method will be released when the paper is accepted.

Visualization Lab Construction Started

After months of planning, the construction of our visualization lab started on Monday. Already, I am impressed with the speed of their work in renovating the space that was a classroom.  Hopefully we can have the equipment installed by the end of the month.  Then we’ll start working on setting up the computers that drive the stereoscopic projection wall and monitor wall, ready for science by the end of the semester.  I plan to publish a few posts that outline the build process of the lab.

30 Nov 2011

  • (abs, pdf) Haschke et al., Metallicity distribution functions of the old populations of the Magellanic Clouds from RR Lyrae stars
  • (abs, pdf) Hopkins et al., Realistic Stellar Feedback & Bulge Formation in Clumpy Disks
  • (abs, pdf) Salvadori & Ferrara, First stars in Damped Lyman Alpha systems
  • (abs, pdf) Hassan et al., Unleashing the Power of Distributed CPU/GPU Architectures: Massive Astronomical Data Analysis and Visualization case study
  • (abs, pdf) Yajima et al., Sub-millimeter brightness of early star-forming galaxies