Lowell Observatory Postdoc Scientist Radiates Enthusiasm, Shares Passion for Astronomy
November 16, 2009 – 11:00 amResearch Using Planetary Nebulae as Probes for Studying Face-on Spiral Galaxies Takes Her from Arizona to Chile to Spain to Malta
Flagstaff, Ariz. – Kim Herrmann greets each visitor to her office here in the Hendricks Center for Planetary Studies with an infectious smile. That smile, plus her enthusiastic, articulate hand gestures while she expertly explains her work at Lowell Observatory as a Postdoctoral Research Scientist, instantly engages a visitor. Herrmann exudes an inspiring enthusiasm for both astronomical research and the science outreach activities she so enjoys.
Herrmann’s extraordinary research and astronomy outreach efforts have already taken her far: it’s a journey from graduate school and a rooftop equipped with telescopes on Penn State University’s astronomy building – to an astronomer’s mecca atop Kitt Peak for observations using the powerful 3.5-meter WIYN
Kim Herrmann working with students at the Dzil Libei
Elementary School on the Navajo Nation in Cameron,
Arizona on Nov. 12, 2009 as part of Lowell Observatory’s
Navajo-Hopi Outreach Program. photo by: Mr. Justin Roberson
telescope – to science conferences in Granada, Spain and the Mediterranean islands nation of Malta – to sharing the night sky with visitors using portable telescopes in front of Lowell Observatory’s historic Slipher Building.
Planetary Nebulae as Probes to Study Spiral Galaxies’ Mass-to-Light Ratios
As her thesis focus for her 2008 Ph.D. from Penn State, Herrmann eventually settled on studying the mass-to-light ratio of spiral galaxies. This research – ongoing during her current job at Lowell – involves using planetary nebulae as tools or probes to gain a better understanding of five nearby, low-inclination galaxies. “I am using the planetary nebulae to test a general assumption that astronomers make: that the mass-to-light ratio is constant throughout the disks of spiral galaxies,” Herrmann explained, both hands positioned for emphasis. While she was in the process of choosing her thesis topic, she had attended various lunchtime science talks at the University. But it was her eventual faculty advisor Robin Ciardullo’s presentation that stuck: something bothered Herrmann. “What if the mass-to-light ratio isn’t constant in this class of galaxies?” she wondered.
To satisfy her curiosity Herrmann uses large, powerful research telescopes in Chile and southern Arizona to constrain the mass limits of the disk components of her five target galaxies. Spiral galaxies have three main components: a bulge (at the center), a flat disk throughout, and a large almost spherical halo with mysterious dark matter. Mostly, she’s using a fiber-optic-equipped, multi-object spectrometer called Hydra on the WIYN consortium’s telescope located at the National Observatory atop Kitt Peak near Tucson. With WIYN and Hydra she has been able to take advantage of data she got during 24 observing nights over the past four years. “I’m looking at the disks of the galaxies and I’m looking at the planetary nebulae in the disks being representative of the disk,” she explained. She added that in simple terms, the planetary nebulae – essentially dying low-mass stars sprinkled all throughout the disks of the galaxies she’s studying – emit a distinctive light signature. “They’re nice and bright and their distinctive monochromatic emission lines make them fantastic targets,” she explained with a big, bright smile.
One of the major goals of her work is to narrow down how much mass exists as dark matter in the galaxies – without making assumptions but instead by measuring the individual disk component itself. “What I do is measure how much mass is in the disk from the motions of the planetary nebulae, and then I know how much mass is in the disk itself,” said Herrmann. “From rotation curves I know how much mass is in the total galaxy, so then I subtract the two to determine how much mass exists as dark matter. My basic result is that the mass-to-light ratio is constant in the inner regions of galaxies but strange things are happening in the outskirts.”
photo at right by Kim Herrmann: M74 is sometimes called the Perfect Spiral. This image is a combination of 10 half hour exposures taken with the Mosaic wide-field imager on the Mayall 4 m telescope at Kitt Peak over the course of three nights in October of 2008. As part of their research, Herrmann and collaborators have taken similar images of the other four galaxies in her sample (IC 342, M83, M94, and M101).
An Early Interest in Science, Multiple Nudges Towards Astronomy
The influences that got Herrmann hooked on astronomy are many and varied. She learned the constellations with her mother at an early age. She was intrigued by the 1997 movies Contact and Hercules, and she read lots of science fiction. She loved the classic movie series Star Wars and identified with Princess Leia. Her parents made a special point of taking Herrmann and her sister to science centers, museums, and national parks when they were growing up.
“I always loved science,” Herrmann said. “We would go to special members-only events – I remember one at the Albuquerque Museum of Natural History – and they were working on dinosaur bones. Later, my family joined an amateur astronomers’ club. We would attend as a family once a month – I really started getting interested in the constellations, in astronomy, then.”
Herrmann’s father is a physicist and her mother a linguist. “My dad could help me with physical sciences and math, and my mother could proofread my essays,” she said. “My parents were huge Carl Sagan fans,” Herrmann recalls with that broad, engaging smile. “When I was little we watched NOVA and Cosmos and all those things.” In the eighth grade, she would help her classmates with their algebra. “I always loved teaching,” she said. During high school Herrmann was one of 90 students selected from among a group of about 900 applicants to attend the Pennsylvania Governor’s School for Sciences, a special summer program. Her research project for it was simulating gravitational lensing using the bottoms of long-stemmed wine glasses, a way to demonstrate part of Einstein’s theory of general relativity.
Princess Leia, a.k.a Kim Herrmann with blaster pistol
defending R2-D2. The Princess has also made numerous
appearances on the rooftop of Penn State’s astronomy
building to assist the public with telescope viewing using
portable telescopes.
An Ambitious Survey of LITTLE THINGS – Dwarf Galaxies
At Lowell Observatory Herrmann was hired to assist a science team with a thorough long-term study of 41 nearby dwarf galaxies. The project’s name combines Local Irregulars That Trace Luminosity Extremes (LITTLE), with The HI Nearby Galaxy Survey (THINGS). The National Science Foundation-funded project aims to find out how little galaxies form stars. The LITTLE THINGS group was granted about 376 hours of observing time for the project using the National Radio Astronomy Observatory’s Very Large Array (VLA) in New Mexico. Kim Herrmann has been analyzing the VLA radio data as part of the project for the year she’s been at Lowell.
“When Kim came to Flagstaff, she had never dealt with radio interferometric data,” said Deidre Hunter, Lowell Observatory astronomer. “But she quickly came up to speed and has now become a local expert. She has calibrated more LITTLE THINGS data than any other person on the team and she is exactly the kind of person we need on the team. She also helped design the LITTLE THINGS team logo.”
The Islands of Malta & Gozo & Measuring Kinematic Mass of Spiral Disks
For an October 2009 science conference on Malta south of Sicily in the Mediterranean Sea, Herrmann presented a talk about her research on spiral galaxies. Coming barely a year after she began her postdoc position at Lowell, the Malta conference was a terrific venue for conferring with colleagues who are also hunting for dark matter in galaxies. Plus, it gave her a chance to do a little sightseeing on a couple of the Maltese Islands.
at right: Marsaxlokk Harbor, Malta. A wild, magical place below: the Azure Window, Gozo Island, Maltese Islands. photos: Kim Herrmann
Addicted to Astronomy Outreach & Education
Working at Lowell Observatory has been a perfect fit for Herrmann. In her first year she’s made significant contributions as a research scientist and she generously volunteers her time helping some of the 80,000 annual visitors to the Observatory explore celestial wonders under Flagstaff’s dark skies. Also, during the past two school years, she has participated in Lowell’s Navajo-Hopi Astronomy Outreach Program. This successful annual astronomy education venture pairs Lowell astronomers with elementary and secondary school teachers and their classes throughout the region’s Navajo and Hopi Nations. Last school year, Herrmann made requisite program visits to Hopi Second Mesa Day School, and this school year she’s working with a teacher partner, Mr. Justin Roberson, and captivating fifth graders at the Navajo Dzil Libei Elementary School north of Flagstaff.
But, perhaps the most interesting activity that keeps her smiling as she points out night sky objects with her green laser pointer, is simply helping visitors to Lowell’s historic Mars Hill campus better understand natural celestial wonders. Herrmann has volunteered many evenings, pointing out constellations, star clusters, planets, and even large bright galaxies. “Being out there with the public, having them look through the telescopes and talking to them – I’m kind of addicted to that,” she said.