Undergrad Research
I was fortunate enough to participate in a variety of different projects while in undergrad at the University of Arkansas and through REUs. While I don't work on these topics anymore, you may still find them interesting or informative.
Completeness Corrections for X-Ray Luminosity Functions
While in undergrad, I worked on my Honors Thesis with Bret Lehmer, who broadly studies X-ray Binaries. My part of the project was to develop the code to insert fake X-ray sources into our Chandra images so that we could estimate the completeness of our source detection. This process is especially important with Chandra data since the PSF is not uniform across the detector; objects near the edge are more dispersed than those on axis. My code was able to model this variation in the PSF to create accurate X-ray sources.
For more, you can read my Honors Thesis here.
You can also access the code here.
Check out the related paper: Lehmer, Eufrasio, Markwardt, et al. 2017
Dragon's Breath and Other Anomalies in WFC3 Images
In the summer of 2016, I participated in the STScI SASP program, working with Matthew Bourque and Katie Gosmeyer. I spent the summer studying anomalies in HST WFC3 images. A portion of my time was spent flagging different anomalies in WFC3 images (I'm now really good at finding Detector and Figure 8 ghosts). However, the majority of my time was spent analysing the dragon's breath anomaly (shown above). This feature is caused by bright stars that fall just outside the edge of the detector, but we did not the range around the detector that would cause this feature. I wrote a program that plots all of the stars around the edge of an image with dragon's breath so a user could mark which star was causing the feature. With this tool we were able to determine that stars within ~ 500 pixels of the edge of the detector could cause this anomaly, so astronomers should avoid choosing fields with bright stars in this region.
You can watch my final presentation for the program here.
You can also access the code I wrote for this project here.
Check out the full paper: Fowler, Markwardt, Bourque, & Anderson 2017
AU-Scale Structure in Diffuse ISM
In the summer of 2015, I participated in the CIERA REU program at Northwestern. I worked with Dave Meyer to look for AU-scale structure in the ISM. Specifically I was looking for changes in the absorption lines (specifically CI) for stars that had HST data taken at least 10 years apart. Such temporal variations would suggest there was structure in the intervening ISM on a scale of < 200 AU. I found only one sightline, toward HD 210809, that had significant variation. The sky position and LSR velocity of the varying absorption lines also corresponded to a previously known edge of an intervening H I supershell discovered by Suad et al. 2012. Therefore, we concluded that this shell was likely responsible for the small-scale structure.
For more info, check out my REU website here.