Kitt Peak REU and Working with CANDELS

Hi! My name is Kirsten Blancato and I am an astronomy and physics major at Wellesley College. This past summer, I had the exciting privilege of being a part of the 2013 Kitt Peak National Observatory Research Experience for Undergraduates (REU) program. For twelve weeks, I worked with CANDELS team member Jeyhan Kartaltepe at the National Optical Astronomy Observatory in Tucson, Arizona.

Working at the National Observatory was truly an amazing experience. I have been in interested in astronomy since I was a child and being able to study astronomy in college has been a dream come true. I was thrilled when I was accepted to work at NOAO the summer after my sophomore year. I had always heard about the amazing work going on at Kitt Peak and could not wait to be there.

Kitt Peak from the Mayall 4-meter telescope
Image credit: Kirsten Blancato

In addition to working on a research project with an astronomer at NOAO, the REU program included many activities including field trips to observatories, observing time at Kitt Peak, and many interesting astronomy lectures. We spent a week in New Mexico, where we visited the National Solar Observatory at Sacramento Peak, the Sloan Digital Sky Survey at Apache Point Observatory, and my favorite of all - The Very Large Array.  Each student also had five nights of observing on Kitt Peak. For a few days at a time we would live on the mountain, observing at night and sleeping during the day.  We were able to observe with the 2.1 meter telescope both in the optical and in the IR.  It was great to meet so many different types of astronomers both while observing and visiting observatories.

But for a majority of the twelve weeks, I was working at the NOAO offices in Tucson with Jeyhan Kartaltepe. I did not know much about extragalactic astronomy before this summer, but was immediately amazed by CANDELS and all of the great science that is being done by the team members. My project focused on high redshift galaxies and how morphology can be used to identify mergers at high redshifts.  Galaxy mergers are thought to play a critical role in galaxy evolution. In the early universe, when everything was closer together, there were many young disk galaxies. As time went on, galaxy collisions eventually formed elliptical galaxies, which are much more common in the local universe. But before we can better understand how galaxies have evolved since the beginning of the universe, we need to be able to identify galaxy mergers at higher redshifts. And this is what my summer work focused on!

Images of high redshift galaxy mergers
Image Credit: Jeyhan Kartaltepe

Using many different data sets from CANDELS, I compiled a data set of around 22,000 galaxies from the GOODS-S, UDS, and COSMOS fields. For each of the 22,000 galaxies, we have visual classification information, redshifts, and several different image statistics. The main problem with identifying high redshift galaxy mergers is that mergers features are much fainter at these distances, making it much harder to see features such as tidal arms. While automated methods for picking out mergers have been developed for low redshift (z < 1) galaxies, more work needs to be done to develop a successful automated method that picks out high redshift (z > 1) mergers. This summer, we looked at how well visually classified mergers and other morphological features were picked out by the different image statistics.

I had a great time learning about galaxy mergers and evolution and at the end of the summer realized that twelve weeks goes by pretty fast.  After the twelve weeks, I had more questions and more things I wanted to explore than I did at the beginning of the summer. I am definitely excited to hear about all of the science that will result from CANDELS and NOAO in the future.

After my summer at NOAO and working with CANDELS, I am very excited to continue on in astronomy. This spring, I will be studying astrophysics abroad at the University of St. Andrew's in Scotland and will then return to Wellesley for my senior year.  After that, I definitely plan to attend graduate school in astronomy.