APS Directory ~ Graduate Students and Their Research Interests

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Graduate Student Information

Piyush Agrawal


Picture of Evan Anders

Evan Anders

I study astrophysical fluid dynamics using computational methods in order to better understand stellar convection and dynamos.


Baylee Bordwell


Picture of Jacob Bruns

Jacob Bruns

My primary research interest is studying exoplanets. I currently work with Phil Armitage on n-body exoplanet system late stage formation & migration simulations.

My undergrad research consisted of photometry based observations of extrasolar planet atmospheres in contrast to similar observations of brown dwarf atmospheres.

Selected Recent Publications:

Beatty, T., et al. 2014. "Spitzer and z' Secondary Eclipse Observations of the Highly Irradiated Transiting Brown Dwarf KELT-1b", ApJ, (submitted)


Picture of Mike Chaffin

Mike Chaffin

Undergrad: Reed College

Major(s): Physics

Advisor: Nick Schneider

Research Group: MAVEN IUVS

I work to build models of the upper atmosphere of Mars in preparation for the MAVEN mission.


Picture of Eric Coughlin

Eric Coughlin

Undergrad: Lehigh University

Major(s): Astrophysics

Advisor: Mitchell Begelman

Research Group: Begelman

I have been working with my advisor, Mitch Begelman, on a model that describe how hyperaccreting black holes modify the gas around them and, more specifically, how this occurs during tidal disruption events. I have also been analyzing the way in which radiation-dominated, relativistic jets interact with their surroundings. Finally, I have been working with Chris Nixon, a postdoctoral fellow in JILA, on numerically modeling the tidal disruption of stars by supermassive black holes.

Selected Recent Publications:

Coughlin, E.R., & Begelman, M.C. 2015, "Viscous boundary layers of relativistic, radiation-dominated jets. II. The free-streaming jet model," ApJ, 809, 2

Coughlin, E.R., & Begelman, M.C. 2015, "Viscous boundary layers of relativistic, radiation-dominated jets. I. The two-stream model," ApJ, 809, 1

Coughlin, E.R., & Nixon, C. 2015, "Variability in tidal disruption events: gravitationally unstable streams," ApJ, 808, L11


Picture of Matteo Crismani

Matteo Crismani

Currently working on the remote sensing instrument (IUVS) aboard MAVEN. Using an observation plan designed for observing ISON, which was destroyed before our observations, I am hoping to characterize the performance of the instrument prior to Mars orbital insertion.

Selected Recent Publications:

Laughlin, G., Crismani, M., & Adams, F. "On the Anomalous Radii of the Transiting Extrasolar Planets" ApJL 729 L7


Picture of Hilary Egan

Hilary Egan

I work on simulations of galaxy clusters. Current simulations fail to reproduce thermal and chemical properties of the intercluster medium. One reason this could be is the current methods of implementing feedback from unresolved sources such as star formation or active galactic nuclei. I'm developing new subgrid models to circumvent the resolution limitations.

Selected Recent Publications:

Egan, H, Smith, B, O'Shea, B.W., Shull. M.J. "Bringing Simulation and Observation Together to Better Understand the Intergalactic Medium", APJ


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Nicholas Erickson

I'm a first year grad student interested in extragalactic astronomy and instrumentation, but open to many topics.


Picture of Wendeline Everett

Wendeline Everett

Undergrad: Oberlin College and Conservatory

Major(s): B.A. Physics and B.M. Music Performance

Advisor: Nils Halverson

I'm a second-year grad student interested in observational cosmology. I currently work on a project analyzing point source populations in CMB maps from the South Pole Telescope.


Picture of Christopher Fowler

Christopher Fowler

Advisor: Laila Andersson

Research Group: LASP

My main research area is data analysis and instrumentation within the planetary science field. I work at LASP - the Laboratory for Atmospheric and Space Physics - on CU East campus. In particular, I've used in-situ Mars Express data to look at atmospheric escape of O+ at Mars. I'm also on the LPW (Langmuir Probe) team for MAVEN, writing software and helping to validate the instrument.

I also play rugby for the local Boulder mens team (www.boulderrugby.com), ski, bike and own a Subaru, as is unofficially required by Colorado law.


Picture of Adalyn Fyhrie

Adalyn Fyhrie

Undergrad: University of California, Berkeley

Major(s): Physics, Astrophysics

I am a first year graduate student. Currently I am not an official part of a research group, but I have an interest in mm/sub-mm instrumentation.


Daniel Gole

Undergrad: SUNY Geneseo

Major(s): Physics

Advisor: Phil Armitage

Currently working on numerical simulations of accretion disks with dead zones. Generally interested in accretion disk phenomena, MHD and fluid instabilities, turbulence, and planet formation.


Picture of Katherine Goodrich

Katherine Goodrich

Undergrad: Boston University

Major(s): Physics

Advisor: Robert Ergun

Research Group: Magnetospheres of Outer Planets

I am currently a third year graduate student working under Bob Ergun. I use observations from planetary magnetospheres to analyze kinetic plasma processes. I'm currently analyzing the properties of plasma turbulence in the bursty bulk flow region of the Earth's magnetosphere. I am also involved in instrumentation analysis for the upcoming Magnetospheric Multiscale (MMS) mission.


Ben Greer

Undergrad: Carnegie Mellon University

Major(s): Physics

Advisor: Juri Toomre

I primarily do local helioseismology using data from the Solar Dynamics Observatory. I focus on improving methods and understanding of systematics in order to push observations deeper into the solar convection zone.


Caitlin Heath

Undergrad: Colorado Mesa University

Major(s): Physics

Advisor: Dave Brain

I work with Dave Brain on the effects of asteroid and comet impacts on the atmospheres of Venus, Earth, and Mars using Monte Carlo modeling (with potential extension into numerical models soon). We want to understand how everything about the impact (e.g. velocity, angle) and impactor (how many comets vs. asteroids, density, volatile content, etc.) change the atmospheres of the three planets.

I also did my Comps II research on modeling of an induced magnetic field due to a subsurface ocean on Neptune's moon Triton. This looked at how to best go about detecting an ocean at Triton with a future mission and how different potential types of oceans would influence the field we might measure.

Selected Recent Publications:

Heath, C.A., Brain, D., 2014. "Evolutionary Modeling of Atmospheric Abundances Due to Impacts at Venus, Earth, and Mars" (in preparation)

Morsony, B.J., Heath, C.A., Workman, J.C., 2014. "Modeling Increased Metal Production in Galaxy Clusters with Pair-Instability Supernovae", Mon. Not. R. Astron. Soc. (accepted)


Picture of Keri Hoadley

Keri Hoadley

Undergrad: Florida Institute of Technology

Major(s): Astrophysics, Mathematical Sciences

Advisor: Kevin France

Research Group: UV Sounding Rockets

I am the lead graduate student for a rocket-bourne experiment designed to look at the atomic-to-molecular transition of translucent cloud material in star-forming regions interacting with the winds of hot, O-B stars in the far ultraviolet (FUV). The Colorado High-resolution Echelle Stellar Spectrograph (CHESS) uses high spectral resolving power (R > 120,000) over a broad band pass in the FUV (100 - 160 nm) to identify multiple species of important atomic and molecular absorption features that inform the observer of the metallicity, temperature structure(s), turbulence diagnostics, and column densities of metals and molecules (H2, CO) in our chosen line of sight. In June 2014, CHESS will launch and observe Beta Scorpii, a multi-stellar system embedded in the Upper Ophiuchus-Scorpius star forming cloud.

To prepare for the modeling work required to understand our observations from CHESS, I am also creating 2D radiative transfer models of molecular gas observed in the inner radii of protoplanetary disks, which depend on the physical properties of the gas as a function of radial distance from the central stellar mass (including temperature, density, height above the mid-plane, and total mass contributing to the observed line profile). ALSO, I'm featured on STARtorialist! http://www.startorialist.com/post/109581976836/toda ys-feature-friday-is-keri-hoadley-a-4th-year

Selected Recent Publications:

Hoadley, K.; France, K.; Nell, N.; Kane, R.; Schultz, T.; Beasley, M.; Green, J.; Kulow, J.; Kersgaard, E.; Fleming, B. "The assembly, calibration, and preliminary results from the Colorado high-resolution Echelle stellar spectrograph (CHESS)", Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 914406 (24 July 2014)


Picture of Bryan Holler

Bryan Holler

Undergrad: University of Maryland, College Park

Major(s): Astronomy & Physics

Advisor: Fran Bagenal

I have been working the past two years with my research advisor, Leslie Young (Southwest Research Institute), on surface spectra of Pluto, Charon, and Triton. Upcoming and ongoing work includes reduction of Keck/OSIRIS data, temporal variations on the surface of Pluto, surface spectra of 2007 OR10 and Salacia, and photometry of Eris.

Selected Recent Publications:

Holler, B.J., Young, L.A., Grundy, W.M., Olkin, C.B., Cook, J.C., 2014. Evidence for longitudinal variability of ethane ice on the surface of Pluto. Icarus 243, 104-110.

Grundy, W.M., Olkin, C.B., Young, L.A., Holler, B.J., 2014. Near-infrared spectral monitoring of Pluto's ices II: Recent decline of CO and N2 ice absorptions. Icarus 235, 220-224.


Picture of Justin Holmes

Justin Holmes

Undergrad: Michigan Technological University

Major(s): Physics

Advisor: Robert Ergun

Currently constructing computational models of plasma double layers and electron phase space holes.

Interested in further computational work analyzing high energy particle acceleration mechanisms and their potential applications to cosmology.

Selected Recent Publications:

R.J. Nemiroff, R. Connolly, J. Holmes, and A.B. Kostinski, 2012. "Bounds on Spectral Dispersion from Fermi-Detected Gamma Ray Bursts", Phys. Rev. Lett. 108, 231103


Picture of Briana Ingermann

Briana Ingermann

I am currently working in Astronomy Education Research characterizing how undergraduates learn the concept of comparative planetology and developing a lecture tutorial to elicit more effective learning.

In the future, I plan to do thesis work looking at how people learn in a planetarium environment and what changes could be made to this environment to improve learning outcomes.

Selected Recent Publications:

Worthey, G., Ingermann, B. A., & Serven, J., 2011. “Ca, Fe, and Mg Trends Among and Within Elliptical Galaxies.” The Astrophysical Journal, 729, 148.

Worthey, G., Hansen, A., Ingermann, B. A., Eld, J. D., & Hawthorne, B. D. “UBVRIJHK Color-Magnitude Diagram of Old Open Cluster NGC 6791.” (In Preparation).


Nick Kruczek


Picture of Jen Kulow

Jen Kulow

Undergrad: Indiana University

Major(s): B.S. Astronomy, B.S. Biology, B.S. Physics

Advisor: Kevin France

I am currently helping with the prep for the launch of SLICE. Provided everything goes smoothly, I will be analyzing the data from the SLICE launch. We are attempting to analyze the local ISM by looking at the spectra of bright UV stars at various distances (inside and just outside the local bubble).


Jesse Lord

I study the large scale convection in the solar atmosphere, specifically the relationship between the quiet sun magnetic field and solar supergranulation. I use large scale MHD simulations to examine convection near the surface of the sun with a code that includes the relevant physics necessary to simulate a realistic photosphere.


Picture of Matthew McJunkin

Matthew McJunkin

Undergrad: Case Western Reserve University

Major(s): Mathematics and Physics

Advisor: Kevin France

I am a fifth year graduate student working on characterizing the environments around and toward young stars. I use ultraviolet observations of carbon monoxide and neutral hydrogen absorption as well as molecular hydrogen emission. Understanding these regions informs us of the physics and chemistry involved in the planet formation process.

Selected Recent Publications:

McJunkin, M., France, K., Burgh, E., Herczeg, G., Schindhelm, E., Brown, J., Brown, A., 2013. "Probing the Inner Regions of Protoplanetary Disks with CO Absorption Line Spectroscopy", ApJ, 766, 12

McJunkin, M., France, K., Schneider, P. C., Herczeg, G., Brown, A., Hillenbrand, L., Schindhelm, E., Edwards, S., 2014. "Direct Measurement of Interstellar Extinction toward Young Stars Using Atomic Hydrogen Lyα Absorption", ApJ, 780, 150

France, K., Herczeg, G., McJunkin, M., Penton, S., 2014. "CO/H2 Abundance Ratio ~ 10^{-4} in a Protoplanetary Disk"


Jacob Miller


Picture of Jordan Mirocha

Jordan Mirocha

Undergrad: Drake University

Major(s): B.S. Physics, B.S. Astronomy

Advisor: Jack Burns

Research Group: CASA/LUNAR

I work primarily on modeling the influence of the first stars and black holes on the sky-averaged 21-cm signal signal. I am most interested in determining how this signal, in conjunction with others, can help us piece together the cosmic star formation and black hole accretion histories, which are two powerful probes of galaxy formation in the early universe.

Selected Recent Publications:

Mirocha, J., 2014, "Decoding the X-ray Properties of Pre-Reionization Era Sources," MNRAS, 443, 1211

Mirocha, J., Harker, G.J.A., Burns, J.O., 2013, "Interpreting the Global 21 cm Signal from High Redshifts. I. Model-independent constraints," ApJ, 777, 118

Mirocha, J., Skory, S., Burns, J.O., Wise, J.W., 2012, "Optimized Multi-frequency Spectra for Applications in Radiative Feedback and Cosmological Reionization," ApJ, 756, 94


Karan Molaverdikhani


Joshua Moloney


Picture of Chris Moore

Chris Moore

Undergrad: University of Iowa

Major(s): B.S. Physics, B.S. Astronomy and Spanish Minor

Advisor: Kevin France

Research Group: UV Instrumentation Rocket Group

I am a forth year student conducting my Ph D. research in the Ultraviolet Instrumentation Rocket Group at CASA. This research consists of developing, fabricating and testing of various deposition techniques of thin film optical coatings to enhance the intrinsic reflectivity of metals for use as the next generation mirrors on future major space missions. These coatings will be spaceflight tested on a sounding rocket payload in the near future as part of my dissertation research.

My other research involves the Miniature X-ray Solar Spectrometer (MinXSS) CubeSat. I am assisting in the characterization of the detector and analysis of science data. MinXSS will measure the x-ray energy distribution of the Sun. I worked with Prof. Mark Rast for my Comps 2 at LASP. I compared synthetic spectra from simulated convective hydrodynamic flows to convective magnetohydrodynamic flows to analyze the effects of magnetic fields on the chemical abundance in the Solar photosphere.

Selected Recent Publications:

Moore, C. S. et al., 2015, The Effects of Magnetic Field Morphology on the Determination of Oxygen and Iron Abundances in the Solar Photosphere, ApJ, 799 150

Moore, C. S. et al., 2014, Recent developments and results of new ultraviolet reflective mirror coatings, SPIE, 9144E..4HM

Moore, C. S., Chamberlin, P. C. and Hock, R., 2014, Measurements and Modeling of Total Solar Irradiance in X-class Solar Flares, ApJ, 787 32M


Picture of Rebecca Nevin

Rebecca Nevin

Undergrad: Whitman College

Major(s): Astrophysics

Advisor: Julie Comerford

I'm a second year grad student working with Julie Comerford on confirming and analyzing dual AGN candidates. I observe with DIS on the 3.5m on Apache Point and code in Python and IDL to parameterize these galaxies at z<0.1.

In the past, I've conducted research on AGNs and recoiling SMBHs as well as instrumentation on the HiVIS spectropolarimeter on the AEOS telescope.


Picture of Ryan Orvedahl

Ryan Orvedahl

Undergrad: Stony Brook University

Major(s): Physics, Astronomy (Math Minor)

Advisor: Juri Toomre

I am interested in computational fluid dynamics and use supercomputers with thousands of cores to conduct my research. I work with Juri Toomre and we are investigating magnetic instabilities that could trigger dynamo action in convectively stable regions of stars, e.g. the radiative zone of the Sun.

Selected Recent Publications:

Zingale, M., Nonaka, A., Almgren, A. S., Bell, J. B., Malone, C. M., & Orvedahl, R. J., 2013, "Low Mach Number Models of Convection in Helium Shells on Sub-Chandrasekhar White Dwarfs. I. Methodology", ApJ, 764, 97


Marcus Piquette

Undergrad: University of Colorado at Boulder

Major(s): Astrophysical and Planetary Science

Advisor: Mihaly Horanyi

Research Group: IMPACT

My research is in the field of dusty plasmas. I work with Mihaly Horanyi doing simulations of plasma environments on airless bodies such as the moon and asteroids. The surfaces of airless bodies need to be better understood in order to mitigate dangerous hazards that affect instrumentation and manned missions.

I will also take over the student lead role for the Student Dust Counter aboard New Horizons which will reach Pluto in the summer of 2015.


Picture of Drake Ranquist

Drake Ranquist


Morgan Rehnberg

Undergrad: Beloit College

Major(s): Physics

Advisor: Larry Esposito

My current work involves developing detection methods for clumps seen in the F ring of Saturn using Cassini UVIS occultation data.

Selected Recent Publications:

Kenneth J. Mighell, Morgan Rehnberg, Robert Crawford, Mark Trueblood, and Larry A. Lebofsky, 2012, PhAst: An IDL Astronomical Image Viewer Optimized for Astrometry of Near Earth Objects, PASP, 124, 1360-1368.


Jessica Roberts


David Schenck

Undergrad: University of Arizona

Major(s): Astronomy, Physics


Picture of Marek Slipski

Marek Slipski

I'm a second year grad student working with Bruce Jakosky. I'm trying to understand the evolution of volatiles in the Martian atmosphere by modeling how various processes affect the abundances of different isotopes.


Julia Stawarz

Undergrad: University of New Hampshire

Major(s): Physics

Advisor: Bob Ergun

I work at both LASP with Bob Ergun and NCAR with Annick Pouquet studying magnetohydrodynamic (MHD) turbulence and its interaction with other plasma processes which occur in space plasmas.

Selected Recent Publications:

Stawarz, J. E., A. Pouquet, and M. Brachet, 2012. "Long-time properties of magnetohydrodynamic turbulence and the role of symmetries," Physical Review E, 86, 036307.

Stawarz, J. E., C. W. Smith, B. J. Vasquez, M. A. Forman, and B. T. MacBride, 2010. "The Turbulent Cascade for High Cross Helicity States at 1 AU," The Astrophysical Journal , 713 , pp. 920 - 934.

Stawarz, J. E., C. W. Smith, B. J. Vasquez, M. A. Forman, B. T. MacBride, 2009. "The Turbulent Cascade and Proton Heating in the Solar Wind at 1 AU," The Astrophysical Journal , 697 , pp. 1119 - 1127.


Picture of Andrew Sturner

Andrew Sturner

Undergrad: Haverford College

Major(s): Physics, Astronomy

Advisor: Robert Ergun

Research Group: Magnetospheres of Planets

I'm in my 3rd year, and am working with the planetary magentospheres group at LASP. I'm currently studying magnetic reconnection using simulations to understand how magnetic field lines break apart and reattach. I also help run CU-STARs, a group aimed primarily at supporting underrepresented freshman STEM majors; we also travel to high school classrooms around Colorado to teach about astronomy and technology.


Evan Tilton

My research focuses on extragalactic astronomy, primarily using spectra to probe the intergalactic medium and active galactic nuclei.

Selected Recent Publications:

Tilton, E. M., Stevans, M. L., Shull, J. M., & Danforth, C. W., 2016, "HST-COS Observations of AGNs. III. Spectral Constraints in the Lyman Continuum from Composite COS/G140L Data," ApJ, 817, 56

Tilton, E. M. & Shull, J. M, 2013, "Ultraviolet Emission-line Correlations in HST/COS Spectra of Active Galactic Nuclei: Single-epoch Black Hole Masses," ApJ, 774, 67

Tilton, E. M., Danforth, C. W., Shull, J. M., & Ross, T. L., 2012, "The Low-redshift Intergalactic Medium as Seen in Archival Legacy HST/STIS and FUSE Data," ApJ, 759, 112


Alexandra Truebenbach

Undergrad: Wesleyan University

Major(s): Astronomy, Physics

Advisor: Jeremy Darling


Samuel Van Kooten


Tristan Weber


Picture of Jordan Wheeler

Jordan Wheeler

Undergrad: University of Missouri Columbia

Major(s): Physics and Math


Picture of Erika Zetterlund

Erika Zetterlund

Undergrad: Augustana College, Sioux Falls, SD

Major(s): Physics, Mathematics, Religious Studies

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