I am interested in studying the formation and evolution of galaxies using primarily observational techniques. My Specifically, I am trying to determine how galaxies assembled their mass over cosmic time and how much the evolution of galaxies is determined by the places in which they reside as they evolve. I address these areas by using a variety of telescopes on the ground and in space to observe galaxies at multiple wavelengths and at multiple epochs. Doing so I can directly track their evolution and the dependence of that evolution on, e.g. their mass and the density of galaxies around them. Progress in these fields will give us a better idea of how our own galaxy formed and how galaxies in the local Universe today attained their present state.
More specifically, my research is split into several areas.
- I study the evolution of galaxies around clusters and groups at intermediate redshifts (z<0.8) as part of a large multi-wavelength campaign to see how galaxies are changed as they enter dense environments. The main component of this survey in the past has been a detailed spectroscopic and multi-wavelength imaging survey of the cores of clusters called the ESO Distant Cluster Survey. In recent years my collaborators and I have undertaken a wide-field spectroscopic survey with the Magellan telescopes in Chile that is allowing us to characterize how galaxies change their properties as they fall into the gravitational wells of clusters and groups. This data set is unique in that we can probe the galaxy properties far outside of the canonical cluster boundaries.
- I am one of the main members of the GOGREEN (Gemini Observations of Galaxies in Rich Early ENvironments) survey, which is the premier spectroscopic survey of clusters and groups of galaxies at z>1. We will uncover how environment quenches star formation and transforms morphology and we will learn how the stellar content of dark matter halos evolves over time.
- I work with an international team to understand the properties of molecular gas emission in distant cluster galaxies. These observations shed light on the gas supplies that fuel star formation. We conduct these observations using ALMA and JVLA observations.
- I am studying the multi-wavelength properties of galaxies in the filaments around the Virgo cluster. We are attempting to understand how the filaments that feel large mass concentrations influence (or don’t) the galaxies passing through them
- I am involved in a research group to study massive compact galaxies that are hosting intense obscured star formation and blowing extremely fast (~1000-2000 km/s) winds. These objects are at z~0.6 and may be examples of rapid self-quenching of galaxies through galaxy-wide Eddington-limited star formation.
I am currently supervising two graduate students and three undergraduates. All of my students are leading their own projects with the expectation that they will write a first author paper and present their works at national or international conferences. The work is funded by grants from the National Science Foundation, NASA, and the University of Kansas. The projects are:
- Kristen Jones
- Mauro Stefanon
- Tyler Desjardins
- Kim Conger is studying the spatial distribution of dust emission and star formation in galaxies that occupy the filamentary region around the Virgo cluster.
- Byron Morales
- Melinda (Mindy) Townsend is characterizing the satellite population of Luminous Red Galaxies using SDSS spectroscopy and imaging from the Legacy Surveys. Where is she now? Mindy successfully defended her PhD in December 2022 and is starting as a permanent outreach astronomer at Dudley Observatory in New York
- Jennifer Cooper is studying the ionized gas distribution in 4 intermediate redshift clusters using HST Grism spectroscopy. Where is she now? Jenn received her PhD in the summer of 2021 and is now working at an Aerospace firm in the Los Angeles area.
- Sinan Deger used Hubble Space Telescope (HST) data to analyze the morphologies of intermediate redshift cluster galaxies as part of an HST Cycle 18 archival program to understand how the morphologies and star formation histories of galaxies are altered as they fall into galaxy clusters. Where is he now? Sinan received his PhD in the Fall of 2019 and is now a postdoc at IPAC in Pasadena
- Justin Mann is using wide-field spectroscopy of intermediate redshift clusters with MIPS images to understand the effect that the local and global environment have on star formation in galaxies. Where is he now? Just received his MS degree in the Summer of 2023 and is working outside of astronomy.
- Donald Lee Brown used deep HST grism spectroscopy to study the stellar populations of a z=1.62 galaxy cluster. His dissertation was done with Prof. Twarog and Anthony-Twarog and the HST project was the subject of his MS degree. Where is he now? Donald received his PhD in 2018 and is now a program director and Insight Data in New York City.
- Brittany Krutty analyzed HST/WFC3 grism data on a z=1.62 galaxy cluster. She will examine the trends of stellar population age with other galaxy physical properties such as stellar mass and color. Where is she now? Brittany received her MS degree in 2015 and is now raising a beautiful family.
- Matthew Russel analyzed HST data on intermediate redshift cluster galaxies. Where is he now? Matt received his MS degree in 2013 and is now working in data science in Kansas City.
- Wesley Sportsman
- Del Endecott
- Freeman Spray
- Anna Davidson
- Caelen “Jacob” Golledge
- Arlo Osler used Spitzer/IRAC mid-infrared data to study the active galactic nuclei (AGN) content of intermediate redshift galaxy clusters.
- Erin Schultz used deep ESO Very Large Telescope data to measure how the age spread of galaxies in a z=1.62 cluster depend on their stellar mass.
- Jeremy Ims used wide-field spectroscopy of intermediate redshift clusters with MIPS images to understand the effect that the local and global environment have on star formation in galaxies. Where is he now? Pursuing a PhD in Aerospace Engineering at KU.
- Alex Galli used Spitzer/IRAC mid-infrared data to study the active galactic nuclei (AGN) content of intermediate redshift galaxy clusters.
- Elliot Orellana
- Taylor Plattner worked on selecting passive galaxies in distant galaxy clusters. Where is she now? Graduated in 2019 and now in Graduate school at Georgia Tech.
- Kaustubh Nimkar worked on selecting passive galaxies in distant galaxy clusters. Where is he now? Graduated in 2019 and now working in data science in Kansas City
- Spenser LaFontaine worked on selecting passive galaxies in distant galaxy clusters.
- Grayson Petter worked on multiple data analysis and reduction projects. His most recent project is to analyze the radio data of a set of compact starburst galaxies at intermediate redshift. He is turning this work into a first-author paper. Where is he now? Graduated in 2019 and now attending graduate school in Astronomy at Dartmouth.
- I am always interested in looking for new undergraduate research students with some introductory astronomy experience as well as some beginning coursework in computer science.
CV and Publications