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University of Wisconsin–Madison

Observational Cosmology

Physics Department, University of Wisconsin-Madison

Keith Bechtol Research Group

Dark Energy, Dark Matter, Neutrinos … Welcome to the research group of Prof. Keith Bechtol at the University of Wisconsin-Madison. We use the whole Universe as a laboratory to explore the fundamental nature of matter, energy, space, and time.

Over the past few decades, astronomical observations have contributed to several distinct lines of evidence for new physics beyond the Standard Model: dark matter, dark energy, massive neutrinos, inflation, and matter/antimatter asymmetry. During this same period, our experimental toolbox has expanded to include observatories spanning the full electromagnetic spectrum, as well as cosmic rays, neutrinos, and gravitational waves.

Currently, our research group focuses on construction, operations, and data analysis for wide-area, time-domain optical and near-infrared imaging surveys of the night sky. We often combine our optical survey data with other data sets to conduct multiwavelength and multimessenger analyses.

Active Projects

  • Large Synoptic Survey Telescope (LSST) – wide, fast, deep. By imaging each patch of the southern hemisphere approximately 800 times over 10 years, LSST is anticipated to catalog more stars, galaxies, and Solar System objects than all previous astronomical surveys combined. LSST is currently under construction in Chile, with first light expected in 2020, and full survey operations beginning in 2022. Keith is the LSST Project Commissioning Science Validation Lead and a full member of the LSST Dark Energy Science Collaboration.
  • Dark Energy Survey (DES) – exploring the dark components of the universe. A unique combination of wide-area coverage and depth allows DES to set competitive dark energy constraints, and to reveal numerous dark-matter-dominated satellite galaxies of the Milky Way. DES begins the fifth season of observations in fall 2017. Keith is co-convener of the Science Release group, and the Milky Way Satellites group. Keith is also leading a program to search for optical counterparts for high-energy astrophysical neutrinos.
  • Magellanic Satellites Survey (MagLiteS) – searching for evidence of hierarchical structure formation within the Local Group. MagLiteS is an NOAO community-time survey to complete an annulus of contiguous  DECam/Blanco imaging around the two largest satellite galaxies of the Milky Way. Keith is Principle Investigator of the MagLiteS project.
  • DECam Local Volume Exploration (DELVE) – new in 2019
  • Fermi Large Area Telescope (Fermi-LAT) – exploring the extreme universe since 2008. Fermi-LAT is a time-domain all-sky survey covering four orders of magnitude in gamma-ray energy. Keith works on the origin of the extragalactic gamma-ray background and indirect dark matter searches.


If you are interested to collaborate with and/or join our research group, please contact Keith. Also, feel free to join our journal club on Thursdays at noon in Chamberlin to learn more about current happenings in cosmology.

  • Keith Bechtol (Assistant Professor)
  • Ross Cawthon (Postdoc) – studies of large-scale structure using galaxy clustering and weak gravitational lensing; photometric redshift calibration and joint cosmology probes with galaxy surveys and gravitational lensing of the cosmic microwave background.
  • Robert Morgan (Grad) – searching for explosive optical transients associated with TeV-PeV astrophysical neutrinos and kilonovae; supernova cosmology
  • Mitch McNanna (Grad) – characterizing the population of ultra-faint galaxies orbiting the Milky Way
  • Jimena Gonzalez Lozano (Grad) – cosmology with double-source-plane strong lens systems
  • Diana Li (Undergrad) – LSST Stack Club
  • Ethan Grover (Undergrad) – ultra-faint galaxy searches
  • Jacqueline Beran (Undergrad) – story for the DArchive
  • Alex Krzyston (Undergrad) – combined analyses of cosmic microwave background and optical survey data

Related Groups on Campus

Madison is home to many active research groups in astrophysics, cosmology, and related fields. Below are a few examples:

  • Prof. Peter Timbie research group – focusing on instrumentation and data analysis for the cosmic microwave background and 21 cm tomography
  • Wisconsin IceCube Particle Astrophysics Center (WIPAC) – studying the universe at the highest energies with neutrino, gamma-ray, and cosmic-ray observatories such as IceCube, HAWC, ARA, and CTA
  • Astronomy Department – many opportunities for collaboration in survey astronomy, targeted follow-up observations, and multiwavelength studies
  • High-Energy Physics – experimental collider physics with the ATLAS and CMS experiments at the LHC, direct dark matter searches with LZ, long-baseline neutrino oscillation experiments, and active theory group


We gratefully acknowledge support from the United States Department of Energy Office of Science. We work at the “Cosmic Frontier” of High Energy Physics.