ned Charlotte Johnson REU 2024

Weeks 9 - 10

Week 9

What's going on with H1743-322?

I may have spoke too soon about progress accelerating last week! Ideally yes, however things have gotten a bit weird with the new target we are investigating, H1743-322. It is very well studied in radio, meaning we would have good coverage of the outburst to compare with our X-ray findings. The issue is our model can't seem to get any real height values of the X-ray corona! I also mentioned we were analyzing two outbursts at once, but they both gave us the same issues. Below is the graph of corona height and radio spectral index over time for the 2009 outburst.

Top panel: Radio spectral index (J. C. A. Miller-Jones et al (2012), found here), Bottom panel: Corona heights

These results are clearly not as meaningful as those for MAXI J1836-194, but once we understood the reason it was obvious why. H1743-322 has an inclination angle of about 75 degrees. An angle of 0 degrees would have us looking at the disk face-on, while 90 degrees would be side on. Because our model uses disk reflection to determine a corona height, it then makes sense why it could not produce answers...it can't see the disk! It also makes it clear why this source is so nice for radio astronomers. Because of it's high inclination angle, you can see both radio jets extending from the sides (see image below from this site).

We simultaneously began analysis for GX 339-4, a very well studied XRB. We have placed more constraints on the model parameters and there is a lot of data to go through because this outburst lasted from January 2010 - March 2011. We are hoping to have this analysis finish up over the weekend. I am getting my poster together as well so will be needing results soon!

This weekend, I tagged along with the solar physics conference to tour the Lewis and Clark Caverns. It was a great trip!


Week 10

The End!?

My poster is now ready for our interdisciplinary symposium on Thursday! I am excited to see what the other REUs have worked on for the summer and of course to share my own results. I additionally produced my final presentation and after some practice, gave that presentation on Wednesday afternoon (see below). I am so thankful for all of the work that has been put into this program...this was truly something special. Working with Dr. Lohfink was encouraging and exciting. I absolutely loved our project and she has taught me so much about research, possible next steps and what those may look like, and about perseverance and positivity. I wish I didn't have to leave!