# Searching for Nearest-Neighbors between Two Coordinate Catalogs

Written by Taro Sato on . Tagged: astro stats

Say I have two catalogs of points, each in two-dimensional space. For each object in a catalog, I want to find the nearest object(s) in the other catalog. I can do this by computing the distances between every single unique pairs of objects and find the ones within a search radius and possibly doing an additional sort. ... Continue reading.

# Half-Light Radii for Various Profiles

Written by Taro Sato on . Tagged: astro math

For a radial profile of $I(r)$, the enclosed flux within the radius $r$ is given by $F(r) = \int_{0}^{2 \pi} d\phi \int_{0}^{r} dr r I(r, \phi) \ .$ I’m only concerned about azimuthal symmetric cases, so $F(r) = 2\pi \int_{0}^{r} dr r I(r)$ . ... Continue reading.

# Installing Bruzual & Charlot 2003 (GALAXEV) on Debian Squeeze

Written by Taro Sato on . Tagged: astro sysadmin Linux

The installation procedure is confusing only if you are not using csh (I use Bash) and if g77 is not available. Otherwise you can simply follow the installation procedure outlined in the official documentation file (i.e., bc03/doc/bc03.ps.gz). First, you definitely need csh and a FORTRAN compiler: ... Continue reading.

# Installing SExtractor on Mac OS X Snow Leopard

Written by Taro Sato on . Tagged: astro sysadmin OS X

(November 25, 2010) I screwed up SExtractor installation for no reason and in an attempt to fix it, I’ve found a few things. After wasting a few hours again, I think this installation note can work for most people who can actually build software from source… I think the usefulness of this note will be limited though, as a new release of SExtractor appears imminent. ... Continue reading.

# Installing HOTPANTS 5.1.10 on Mac OS X Leopard

Written by Taro Sato on . Tagged: astro sysadmin OS X

You must love the name, but what the software does is far from sultry; it’s a piece of geekware. Anyways, I needed to edit files when I install HOTPANTS, photometric alignment utility by Andrew Becker. Here is my installation note before I forget. ... Continue reading.