Astronomy In The Andes – Duluth Student Studies Galaxies With The Pros

Shane Loeffler in the Andes Mountains near Cerro Tololo Observatory in Chile. Loeffler’s helping researchers study star types in distant galaxies. Credit: Sarah Burkhart

Today we have something special – a guest blog written by Shane Loeffler, an undergraduate student studying geology and astronomy at the University of Minnesota-Duluth.

Shane works at the planetarium on campus, which is where we met. Earlier this year he was accepted into the Research Experience for Undergraduates program to work alongside professional astronomers in Chile.

Here he shares what it’s like to work in the heady environment of a professional observatory. Enjoy!

I’ve been a lucky guy.  Back in October I applied for a National Science Foundation funded Research Experience for Undergraduates (REU) program that would take me to the Cerro Tololo Inter-American Observatory (CTIO) for 10 weeks of astronomical research and observing.  This program takes six students from the states and two students from Chile to perform mentored research with an astronomer from the observatory.

The 4-meter Blanco telescope … and a visiting fox. Credit: Shane Loeffler

We all arrived in Chile in early January, trading one of the most wintery of winters in recent memory for a mid-summer’s day that hasn’t yet ended.  The observatory has a piece of property known as the Recinto, located in the coastal city of La Serena, where most of the staff lives and works. The REU students take over Casa 13, a modest but functional house that is somehow still standing after all these years of student-induced abuse.

We were given a quick tour of the city by the director of the REU program, Dr. Catherine Kaleida, who gave us a rundown of the quirks of Chilean Spanish, from things like how much to tip the grocery baggers, to just generally where we are, where we should be, and where we should avoid.  We were then fortunate enough to get a tour of the CTIO and Gemini Observatories by Dr. R. Chris Smith, a member of the team that won the 2011 Nobel Prize for determining that the universe’s expansion is indeed accelerating, not slowing down.

Cerro Tololo Observatory complex seen from Pachon. The complex houses multiple telescopes and is located near La Serena, Chile at an altitude of 7,218 feet (2200-meters). Credit: Shane Loeffler

After a scenic drive through the valley from La Serena and finally up to the summit of Cerro Tololo, we found ourselves on a mountain covered in the tools that allow us to probe some of the biggest questions humans are able to muster.  Our first stop was the enormous 4-meter (157.5 inch) Blanco telescope.   An elevator ride to the top level was required before we could see the massive machinery that makes the telescope tick.  Also on Cerro Tololo are the SMARTS meter class telescopes, one of which each student got two nights on to point at objects of our choosing, an unbelievable privilege.

Shane (third from left) with fellow mentees at the 315-inch mirror of the Gemini South telescope at Cerro Pachon. Second from right is Dr. Catherine Kaleida,  student coordinator for the REU program at CTIO and research mentor. Credit: Josh Frechem

We left Tololo for Cerro Pachon, home of the 8.1-meter (319 inch) Gemini South Telescope and 4.1-m (161-inch) SOAR telescope.  Gemini was truly impressive. Its 8 meters of shining mirror moves smoothly, silently, as it tracks the sky. We were treated to a display of its laser driven adaptive optics system after nightfall.

The 319-inch Gemini South telescope is housed in this dome. Click to watch a video about the dual Gemini telescopes, one in Chile and the other in Hawaii. Credit: Shane Loeffler

Day to day life here for the students consists of working on our research projects and venturing around the city of La Serena. Oftentimes during the week we will have a speaker come to present their research or area of expertise.

Subjects so far have included a talk by Dr. Chris Smith about his Dark Energy Research, a telescope design talk by Dr. David James, a fascinating talk about hunting for meteorites in the Atacama desert by Michael Warner, a look into the future of astronomical research Dr. Guillermo Cabrera and how to deal with the huge datasets that it will create, and a presentation by Dr. Pat Seitzer on the increasing problem of space debris and humanity’s attempt to keep track of all the dead satellites cluttering valuable orbit space.

Examining meteorites brought in by meteorite hunter and researcher Michael Warner. Credit: Dr. Isabel Hawkins

In addition to these seminars, we can interact with the staff of CTIO and Gemini by attending weekly Science Tea and Science Coffee gatherings.  At these casual meetings astronomers talk about recent discoveries, problems and triumphs of their own research, and really anything science related.

These meetings have been the highlight of my time here. It’s an unbelievable privilege to be able to sip a bit of coffee and nibble a cookie while truly brilliant people discuss their passions, which happen to be of the insanely interesting sort.

For my research, I am working with the REU program director, Catherine Kaleida, on a project titled “Comparing Stellar Populations Across the Hubble Sequence.”  The Hubble sequence is we humans drawing lines in the sand. It is a classification scheme that organizes galaxies into different types based on their shape.  We are looking at nearby galaxies for systematic changes in their color and brightness with the hope of improving galactic formation models. To do this we take what are called radial profiles, essentially looking at the center a galaxy and moving outward, watching for any trends.

Spiral galaxy NGC 7328 in Pegasus, one the observing targets for which Shane Loeffler is crunching data to determine the distribution of red stars in the galaxy. Credit: Wikisky

Past work has shown that, in the visible spectrum, faint spiral galaxies tend to get redder as you move outward from the center, brighter spiral galaxies tend to get bluer, and elliptical galaxies mostly have flat gradients or get slightly bluer with radius. The data I’m working with is in the infrared, allowing us to see if these trends hold for a redder portion of the spectrum.

Three mechanisms have been proposed to cause these brightness changes. One is metallicity, meaning the metal content of the stars, where more metal produces redder light. (“metals” in astronomy are elements other than hydrogen and helium). The second is dust, which absorbs bluer wavelengths, leading to a reddening of the observed light. Finally, lower mass stars burn cooler and are thus redder.

Elliptical galaxy IC 1639 in Cetus is another galaxy in observing program. Credit: Wikisky

We aim to find out the relative contributions of each possibility. In addition, old, low mass stars make up most of the mass in galaxies and these shine brightest towards the red end of the spectrum, making the infrared ideal to trace the mass distribution throughout a galaxy and thus its mass-induced structures such as bars and spiral arms.

So far, I have been reducing data from the ISPI instrument on the 4-meter Blanco telescope.  Data reduction’s purpose is to remove effects caused by both the detector and the sky so that we can look at a final set of images that appear to be taken above the atmosphere from some ideal instrument that introduces no artifacts. Infrared data is particularly challenging to reduce because the sky shines significantly in that part of the spectrum.

Currently I’m in panic mode, trying to finish the last of my reduction before the end of the program in two weeks.  This experience has given me opportunities I could have never dreamed of.  From performing true astronomical research at a world class observatory, to the absolutely amazing people. I’ve met and become great friends with, to the opportunity to travel in a wonderful new part of the world.  It’s all just too good to be true; I’m still half expecting to wake up to the sound of my alarm.

2 Responses

  1. Jim Egstad

    What a tremendous opportunity for these students…….and just look at the size of that telescope…..the telescope photo reminds me that I probably clean up around here…….and think of the interesting lives some of theses students may lead as a result of this experience.

    An inspirational post…..most appreciated!

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