Professor of Physics and Astronomy
Cosmology, astrophysics, and fundamental physics: studying inflation, dark energy, dark matter, neutrinos, galaxy clusters, and galaxy evolution using cosmic microwave background and sub-mm measurements. Detector arrays and applied superconductivity: low-temperature detector arrays, superconducting detectors, transition-edge sensor bolometers, SQUID measurement systems, device physics, sub-Kelvin refrigeration. Astronomical optics and receivers: optics design, optical coatings, material properties, cryogenic instruments.
Our research focuses on developing new instrumentation to study the formation and evolution of the universe through precision measurements of microwave radiation. Past measurements of the cosmic microwave background (CMB) provided an exquisite picture of the early universe, which combined with astronomical observations at other wavelengths led to strong evidence that we live in a dark energy and dark matter dominated universe; however, we still do not fully understand fundamental aspects of the universe. What are dark energy and dark matter? Did inflation occur in the early universe, and can we understand it? How did the primordial fluctuations evolve into galaxies, stars, and planets? What physical models best describe the past, present, and future of the cosmos?
The instruments we develop help address aspects of these questions through more sensitive observations at millimeter and sub-millimeter wavelengths. We survey the CMB temperature and polarization in unprecedented detail, enabling a wide range of science objectives, including: new constraints on the physics of inflation, new probes of dark energy and modified gravity, characterization of the dark matter distribution, measurements of the neutrino mass sum, and the discovery of both galaxy clusters and high-redshift galaxies.
We played a significant role in building and observing with the six-meter Atacama Cosmology Telescope (ACT), located at 5190 meters elevation in the Chilean desert from 2008-2022. The ACT data has led to a variety of results, including first detections of the power spectrum of CMB gravitational lensing and the kinematic Sunyaev-Zel'dovich effect and some of the best constraints on the Hubble constant yet. While we continue to analyze ACT data, we are now working on developing and deploying new instruments for the CCAT Observatory and Simons Observatory as well as the longer term development of CMB-S4 to measure microwave radiation with far better sensitivity than the ACT.
Another exciting aspect of our research is that advances in millimeter and sub-millimeter radiation measurements are largely being driven by the development of new superconducting and optical techniques. We have helped to design, build, and deploy some of the largest arrays of superconducting detectors yet, with thousands of transition-edge sensor (TES) detectors cooled to sub-Kelvin temperatures. TES detectors are becoming a widely used technology spanning eight orders of magnitude in detection energy (from CMB bolometers to gamma ray microcalorimeters). For the CCAT Observatory we are now developing large arrays of superconducting Kinetic Inductance Detectors (KIDs), which are particularly well suited for sub-millimeter measurements. To enable readout of even larger superconducting detector arrays we collaborate on new measurement technologies, and are developing new optics and instrument designs to couple to these arrays in next generation observatories. We also work in the Cornell Nanoscale Facility developing new optics and detector microfabrication techniques that can be tested and integrated in our laboratory.
Y. Li, E. Biermann, S. Naess, et al. ”The Atacama Cosmology Telescope: Systematic Transient Search of 3-Day Maps,” in review (2023). arXiv:2303.04767
CCAT-Prime Collaboration, et al. “CCAT-prime Collaboration: Science Goals and Forecasts with Prime-Cam on the Fred Young Submillimeter Telescope,” Astrophysical Journal Supplement Series (2023). DOI:10.3847/1538-4365/ac9838
E. M. Vavagiakis, C. J. Duell, et al. “CCAT-prime: design of the Mod-Cam receiver and 280 GHz MKID instrument module,” Proceedings of the SPIE, Volume 12190 (2022). DOI:10.1117/12.2630115
Z. B. Huber, Y. Li, E. M. Vavagiakis, et al. "The Simons Observatory: Magnetic Shielding Measurements for the Universal Multiplexing Module," Journal of Low Temperature Physics (2022). DOI:10.1007/s10909-022-02875-w
E. M. Vavagiakis, P. A. Gallardo, V. Calafut, S. Amodeo, et al. "The Atacama Cosmology Telescope: Probing the Baryon Content of SDSS DR15 Galaxies with the Thermal and Kinematic Sunyaev-Zel'dovich Effects," Phys. Rev. D 104, 043503 (2021). DOI:10.1103/PhysRevD.104.043503
S. K. Choi, M. Hasselfield, S.-P. Ho, B. Koopman, M. Lungu, et al. "The Atacama Cosmology Telescope: A Measurement of the Cosmic Microwave Background Power Spectra at 98 and 150 GHz," Journal of Cosmology and Astroparticle Physics 12:045 (2020). DOI:10.1088/1475-7516/2020/12/045
S. K. Choi, et al. "Sensitivity of the Prime-Cam Instrument on the CCAT-prime Telescope," Journal of Low Temperature Physics (2020). DOI:10.1007/s10909-020-02428-z
S. C. Parshley, M. D. Niemack, R. Hills, et al. "The optical design of the six-meter CCAT-prime and Simons Observatory telescopes," Proc. SPIE 10700, 1070041 (2018). DOI:10.1117/12.2314073
M. D. Niemack, "Designs for a large-aperture telescope to map the CMB 10X faster," Applied Optics 55:7, 1688 (2016). DOI:10.1364/AO.55.001686