Faculty Research Interests

Tom Abel : Numerical Cosmology

Tom's current research focuses on studying the formation and evolution of galaxies with new numerical techniques, however, he enjoys all areas of non-linear physics which can be addressed using supercomputer calculations! His research interests span dark matter dynamics, the physics of collisionless shocks, investigating the role that cosmic rays and magnetic fields play in the formation and evolution of galaxies, modeling the formation of stars and black holes as well as turbulence, and applications of numerical general relativity.

Visualizations of Dark Matter / Large Scale Structure by R. Kähler and T. Abel. Simulation credit to O. Hahn and T. Abel.

Daniel Akerib : Dark Matter

Together with Tom Shutt, Dan works on the LUX and LZ dark matter experiments to search for dark matter in the form of Weakly Interacting Massive Particles, or WIMPs. The detectors use liquid xenon as a target medium in a time projection chamber, or TPC. The Large Underground Xenon (LUX) experiment is currently operating a 250-kg target in the former Homestake gold mine in the Black Hills of South Dakota. Preparations are underway at SLAC to design and build the 7-ton successor, known as LUX-ZEPLIN (LZ). The group is involved in many aspects of data analysis, detector design, xenon purification, control andreadout systems, and detector performance studies.

Steven Allen : X-ray Astronomy and Observational Cosmology (XOC)

Steve is interested in the physics of the most massive objects in the Universe and how we can use them to probe how the Universe evolved. Steve and his group are currently focused on understanding the astrophysics of galaxies and of galaxy clusters using multi-wavelength observations, and on using large, statistical samples of these objects to probe the natures of dark matter, dark energy and fundamental physics. More information regarding ongoing research and a list of Steve's current group members can be found here.

Roger Blandford : Theoretical Astrophysics

Roger has broad interests in particle astrophysics and cosmology. Roger and his group are currently working on studies of gravitational lensing, compact objects (black holes, neutron stars and white dwarfs) and cosmic rays, tackling difficult questions such as the unknown nature of the gamma-ray flares of the Crab Nebula. He is interested in topics which range from pure theory through phenomenological studies to analysis of observational data. Some of his groups research is strongly computational but plenty is not.

Patricia Burchat : Observational Cosmology, LSST Dark Energy Science Collaboration, Gravitational Lensing

Pat and her research group are currently working hard as part of the exciting Large Synoptic Survey Telescope Dark Energy Science Collaboration in the general area of gravitational lensing. Her group is using analytic calculations, simulations and existing astronomical images to thoroughly understand potential systematic biases and challenges in extracting accurate and precise measurements of cosmic shear from gravitational lensing with current and future surveys. Current projects include the study of chromatic effects and blended objects.

 

NASA/ESA image of strong lensing due to the galaxy cluster Abell 2218.

Robert L. Byer : Lasers and Nonlinear Optics

Bob's current research is directed towards precision laser measurements which are used in support of the detection of gravitational waves and in laser particle acceleration. Bob's group and others are involved in developing nanostructured chips, smaller than a grain of rice, in which electrons can be accelerated at a rate 10 times higher than conventional technology.

Blas Cabrera : Dark Matter

Blas's main research efforts are directed towards the search for dark matter in the form of WIMPs or Weakly Interacting Massive Particles. Blas is Spokesperson for SuperCDMS Collaboration. The SuperCDMS Soudan experiment is now operating in northern Minnesota and the SuperCDMS SNOLAB experiment has just been approved by NSF & DOE as one of two second generation WIMP search experiments.

super dms
One of SuperCDMS's state-of-the-art detectors. 

 

 

Sarah Church : Cosmic Microwave Background Radiation

Sarah's group builds instrumentation to observe the Cosmic Microwave Background radiation (CMB) at millimetre wavelengths. The CMB is a virtually pristine relic of conditions in the universe approximately 400,000 years after the Big Bang and by studying it we can test our understanding of the laws of physics in the extreme conditions that occurred in the first few moments after the Big Bang. Sarah's group use telescopes located at the best sites in the world for millimetre wavelength astronomy, including the South Pole, the Chilean Andes, and Mauna Kea in Hawaii.

Peter Graham : Beyond the Standard Model

Peter is broadly interested in theoretical physics beyond the Standard Model, including cosmology, astrophysics, general relativity, and even atomic physics. The Standard Model leaves many questions unanswered including the nature of dark matter and the origins of the fundamental fermion masses, the weak scale, and the cosmological constant. These and other clues such as the unification of the forces are a guide to building new theories beyond the Standard Model. Peter's group are interested in inventing novel experiments to uncover this new physics.

Courtesy Fermilab Visual Media Services.

Giorgio Gratta : Fundamental Particles and Interactions

Giorgio's research is centred on the understanding of fundamental particles and interactions using tools borrowed from AMO, nuclear and particle physics. Giorgio's group are operating the largest double-beta decay experiment in the world (EXO-200) that is producing high sensitivity results on the mass and nature of neutrinos. His group are also investigating the nature of gravity at a scale near 1 micron using submicron size quartz beads trapped in laser fields in vacuum, and have a program to develop imaging detectors for gamma-ray astronomy as well as novel radiation detectors for application in homeland security and medical physics.

Steven Kahn : Large Synoptic Survey Telescope

Steve is the Director of the Large Synoptic Survey Telescope (LSST), a major new facility currently under construction, that will enable a wide array of scientific investigations ranging from studies of moving objects in the solar system to the structure and evolution of the universe as a whole. His research group is primarily working on the design and development of that facility, and its application to research in fundamental cosmology. They are building and testing laboratory prototypes of components of the LSST camera, and developing and utilizing detailed simulations to investigate systematics that may arise in studies of cosmic shear. Prior to his engagement with LSST, Steve was an X-ray astrophysicist, concentrating on the design of instrumentation and analysis of data associated with high resolution X-ray spectroscopy of cosmic sources. He maintains an interest in that field, although at a low level, given his commitments to LSST.

The Large Synoptic Survey Telescope (LSST).

 

Chao-Lin Kuo : Cosmic Microwave Background Radiation: Instrumentation and Cosmology

Chao-Lin’s group use the most ancient light, the Cosmic Microwave Background (CMB) radiation, emitted when the universe was in its infancy to shed light on the question of how the universe began. Currently Chao-Lin's group are involved in a number of experiments such as BICEP/BICEP2/Keck Array and have been working hard on detecting primordial B-mode polarization. His group are involved in both he design and construction of instruments as well as the data analysis and theoretical interpretation.

BICEP2 first detection of B-modes. Credit the BICEP and Keck Array Team.

Bruce Macintosh : Adaptive Optics and Extrasolar Planet Imaging

Bruce's main focus is the direct detection and characterization of extrasolar planets and the use of adaptive optics technology to control light. Bruce is Principal Investigator for the Gemini Planet Imager (GPI) instrument which was commissioned and saw first light in late 2013. Bruce will lead a 600-star survey to discover and spectroscopically characterize young giant extrasolar planets around nearby stars. A new laboratory will be used for  developing exoplanet instrumentation for future ground and space-based telescopes, and applying adaptive optics to other applications such as microscopy. Bruce is also involved in preparations for the proposed exoplanet coronagraph on the WFIRST-AFTA telescope and other approaches to studying extrasolar planets.

Roger Romani : Neutron Stars and Black Holes: Observations, Modelling and Theory

Roger is interested in a variety of topics in high energy astrophysics and cosmology. Much of Roger's group are currently focused on understanding the cosmic gamma-ray sources discovered by the Fermi Space telescope, principally pulsars and blazars. This inherently multi-wavelength question requires them to use telescopes all over the world and in space in order to assemble data on these objects and then to develop and test theoretical models to explain what we see. 

Aaron Roodman : Observational Cosmology

Aaron's current research focus is the study of dark energy using images from the ongoing Dark Energy Survey (DES) and the  future Large Synoptic Survey Telescope (LSST). He is interested in studying dark energy using both galaxy clusters and weak gravitational lensing. His research group connects instrumental work, in particular active optics and wavefront measurements at DES and a program of camera-wide testing at LSST,  with cosmology measurements. For example, they are developing a new method to characterize the telescope+camera point spread function using optical data, to be part of the weak lensing data analysis at both DES and LSST.

Philip Scherrer : Solar Physics

Phil's main research interests are in the structure and dynamics of the interior of the sun, how this affect solar activity and through this its effects on terrestrial systems. Phil's group’s primary emphasis is on the structure and dynamics of the solar interior using techniques of helioseismology. His group are interested in both developing instrumentation for solar observatories and in the data analysis of solar magnetic fields from space and from the ground.

Rafe Schindler : Large Synoptic Survey Telescope

Rafe and his group are working hard on the development and commissioning of the upcoming Large Synoptic Survey Telescope (LSST) a next generation ground based optical survey telescope. The LSST group at KIPAC are working both in the lab, developing the state-of-the-art technologies necessary to preserve the LSST camera’s image quality during operation and building computer simulations of the camera and telescope performance -- a  novel area being pioneered by LSST.

Leonardo Senatore : Early Universe Cosmology; Growth of Structure

Leonardo is interested in understanding how the universe began and evolved to its present form. Cosmological observations are providing us with a huge amount of data, which allows us to test our theories about inflation, eternal inflation and its alternatives, and about the growth of structures in our universe, to an unprecedented level. Leonardo and his group are involved in both developing the theory and analysis of cosmological data and are working to bridge the gap between theories of the early universe and current and future data.

Thomas Shutt : Dark Matter

Together with Dan Akerib, Tom works on the LUX and LZ dark matter experiments to search for dark matter in the form of Weakly Interacting Massive Particles, or WIMPs. The detectors use liquid xenon as a target medium in a time projection chamber, or TPC. The Large Underground Xenon (LUX) experiment is currently operating a 250-kg target in the former Homestake gold mine in the Black Hills of South Dakota. Preparations are underway atSLAC to design and build the 7-ton successor, known as LUX-ZEPLIN (LZ). The group is involved in many aspects of data analysis, detector design, xenon purification, control andreadout systems, and detector performance studies.

The LUX detector situated in its water shield at the 4850' level of the Sanford Underground Research Facility.

Risa Wechsler : Computational Cosmology and Galaxy Surveys

Risa and her group work on a range of topics in cosmology and astrophysics, with a focus on the formation of cosmological structure in the Universe, its impact on galaxy formation, and its use in determining the nature of dark matter and dark energy. Risa's group builds and analyzes numerical simulations and develops models of galaxy formation for comparison with large observational datasets, and develops new techniques to learn about the dark side of the Universe from these data.  Her group is actively involved in the ongoing Dark Energy Survey (DES), as well as the largest future planned surveys including the Dark Energy Spectroscopic Instrument (DESI) and the Large Synoptic Survey Telescope (LSST).

Galaxy cluster formation. Visualization: R. Kaehler. Simulation: H. Wu, O. Hahn, R. Wechsler.

Research interests of KIPAC Scientific Staff

Zeeshan Ahmed : Cosmic Microwave Background

Zeesh is an observational cosmologist who studies the relic blackbody radiation of the early universe, called the Cosmic Microwave Background (CMB), to understand the origin and composition of the Universe and find answers to some perplexing questions in fundamental physics. With CMB team members at KIPAC, SLAC and Stanford, Zeesh builds CMB cameras and analyzes data generated by them. He is a member of the BICEP/Keck, South Pole Telescope (SPT-3G), Simons Observatory and CMB-S4 scientific collaborations. His current research interests include experimental bounds on cosmic inflation from CMB polarization, searches for dark matter using CMB data, and development of next-generation CMB camera readout technologies. Recent hardware development in SLAC’s CMB lab, with a focus on GHz superconducting microresonators, has cross cutting applications in CMB imaging, X-ray and particle detection, and beyond-SQL measurements.

 

Daniel Gruen : Observational Cosmology

Daniel's main research interest is weak gravitational lensing as a tool to study large structures in the Universe, such as galaxies and clusters of galaxies. The census and evolution of these structures is interesting in its own right, but it can also give us a better understanding of two of the greatest mysteries of modern physics, dark matter and dark energy. To reach that goal, Daniel's group develops new methods in statistics and data analysis for the extraction of reliable and powerful information from optical surveys and applies them to the unprecedented data sets DES, DESI and LSST are collecting now and over the coming years.

 

DES Observations of Galaxy Cluster MACS J0416

Grzegorz M. Madejski : X-ray and Gamma-ray Astronomy and Astrophysics

Greg's research interests are mainly in extragalactic high-energy astrophysics. This includes (1) studies of active galactic nuclei, and an associated formation and evolution of relativistic jets; and (2) studies of clusters of galaxies, and in particular the processes responsible for the heating of the X-ray emitting intra-cluster gas. Besides taking advantage of data from the Fermi Gamma-ray Observatory, Greg is involved in analysing and interpreting observations performed with NuSTAR, a recently-launched NASA satellite, sensitive in the hard X-ray band.

Phil Marshall : Observational Cosmology

Phil's research interests are in observational cosmology using gravitational lensing: weighing galaxies, and measuring the expansion rate of the Universe. He is a member of the H0LiCOW and STRIDES collaborations, modeling time delay lenses in order to measure the Hubble constant, and is active in the  Large Synoptic Survey Telescope (LSST) Dark Energy Science Collaboration (DESC) Strong Lensing working group, helping design and implement its strong lensing science analysis. LSST presents astronomers with a new scale of Big Data problems, the solutions to which will necessarily involve either innovations in automated inference, or large numbers of people, or both: Phil's research is focused on strong lensing, but the methods he is investigating with the KIPAC students and postdocs have much wider applicability. Phil was LSST DESC Spokesperson in 2017-2019, during which time he led the implementation of the collaboration's operations plan. He is currently Deputy Director of LSST Operations, thinking about how to set up the LSST Facility to successfully deliver the data products needed by, for example, the DESC's cosmology analysis.

Research interests of KIPAC Emeritus Faculty

Elliott D. Bloom : Fermi LAT; Indirect Searches for Dark Matter

Elliott spends most of his research time working on the analysis of Fermi-LAT data, the Large Area Telescope on the Fermi Gamma-ray space observatory which was constructed right here at SLAC! He is primarily interested in high energy searches for dark matter and new physics, and in understanding the diffuse gamma-ray background. 

David Burke : Observational Cosmology with Large Surveys: DES and LSST

David's current projects are focusing on the development of scientific analyses for the Dark Energy Survey (DES). The DES is an exciting, broad ground-based optical survey which started taking data in 2013. It is measuring cosmological parameters through the use of gravitational lensing, studies of clusters and large scale structure of galaxy populations. Presently David's work is aimed at optimizing the performance of instrument operations and data reduction, and development of scientific analysis techniques using​ simulations and the survey data set. 

The Blanco 4-meter Dark Energy Survey telescope which holds the Dark Energy Camera at the Cerro Tololo Inter-American Observatory in Chile. 

Robert V. Wagoner : Theoretical Astrophysics

Bob has wide research interests in the field of gravitational astrophysics. Bob is interested in oscillations of accretion disks around black holes, and other signatures of very strong gravitational fields, sources of gravitational radiation, and their detection by LIGO and other facilities, scalar-tensor theories of gravitation and physics of the early universe.

A black hole accretion disk. Credit C. Perez.