Peter Yoachim

Reduced data cubes (65 MB) from VIRUS-P observations of nearby galaxies. These data should eventually be released with the larger VENGA survey, but until then I'll post them here.

In Yoachim et al 2009, we used OGLE data to construct template light curves of Cepheid variables. This includes short period Cepheids and stars pulsating in the first overtone mode. This IDL code allows one to fit a sparsly observed Cepheid light curve very accuratly (or do I mean precicely? Probably both.). If you have photometry of a Cepheid in V and I, this code can fit average magnitudes, period, and phase even if the data is noisy and/or not optimally covered in phase.

Update --Shapee and Stanek used the code to fit Cepheids in M101. They found they needed an extra term to tune the amplitude of pulsation. My guess is that this is a metallicity effect. These templates are dominated (especially at short periods) by the low metallicity SMC and LMC. M101 is a massive spiral and presumabaly metal rich, so it's not too surprising that the pulsation shapes are not a perfect match.

Download Cepheid period-magnitude fitting IDL code.

Even Better: Cepheid templates in B, V, and I.

This tar ball includes my personal stash of IDL code including an implementation of the Numerical Recipes two-dimensional Kolmogorov-Smirnov test (KS-test). IDL tar ball.

Here is an IDL generated page with the descriptions for all the routines.

For my thesis, I made extensive use of the MPFIT curve fitting software to fit structural features to images of nearby galaxies. I have made a tar-ball of IDL code that includes examples of how to implement custom fitting functions and weighting schemes here.