The arXiv map


The arXiv is the de-facto repository for preprints in astrophysics. The arXiv map (inspired by sites like Newsmap and Map of the Market) provides a quick interface to today's astro-ph submissions. Articles are grouped and color coded by category.

The arXiv map is an example of a treemap, and is written in Processing.



I study molecular clouds -- the birthsites of stars and planets. A widely used statistic in this field is a molecular cloud's column density distribution (that is, the histogram of pixel values in a column density map). Many molecular clouds possess similar column density distributions, and the reason for this "universality" continues to inspire new research.

A major limitation to the column density distribution is that it is ignorant of a cloud's internal substructure -- the pixels in a column density map can be arbitrarily rearranged without changing the histogram. FlexibleHistograms is a tongue-in-cheek demonstration of this limitation. On the left is a column density map of the rho-Ophiuchus molecular cloud, as presented in this paper by Marco Lombardi and collaborators. By hitting the "Transform" button, you can rearrange these pixels to form the image on the right. There is an exact match between the pixels in each image -- hover your mouse over either image to see the corresponding pixel in the other one. As a consequence, the distribution of pixels in the two images are identical.

FlexibleHistograms is meant to demonstrate that, despite their similar column density distributions, molecular clouds may have interesting structural differences among them. Other statistical approaches are needed to tease out these differences.

This applet is written in Processing. The transformed images are generated to resemble template images retrieved from Wikipedia.