Seminar

"Probing the Dark Sector: Implications of DESI's Dynamic Dark Energy Results"

Sven’s (UCSC) scientific journey has been shaped by trying to ensure accurate and precise results from weak lensing surveys. His contributions to this field are both direct investigations of potential systematic biases (such as variable survey depth) as well as the establishment of higher-order lensing statistics (persistent homology and third-order shear statistics, in collaboration with Pierre) for a robust cosmological inference. As a member of DESI, he performed the validation of Galaxy Lensing measurements for subsequent cosmological analyses.

Woorak Choi is a postdoctoral fellow at McMaster University. He completed his PhD in 2024 at Yonsei University, South Korea. Woorak's research focuses on understanding the evolution of the ISM and star formation in extreme environments, ranging from galactic centers to galaxy clusters. As a radio astronomer, he primarily uses radio telescopes such as ALMA and VLA, but has recently begun working with JWST data. Woorak is also interested in incorporating numerical simulations to complement observational studies.

Jiaming Pan is a Ph.D. candidate in Physics at the University of Michigan. His research focuses on constraining modified gravity and dark energy to understand the physical origin of cosmic acceleration. He is an active member of the Dark Energy Spectroscopic Instrument (DESI) collaboration, where he has contributed to analyses of dark energy and tests of gravity, including extended dark energy analysis with BAO measurements and modified gravity constraints from full-shape clustering. He is also developing methods to use gravitational-wave “standard sirens,” particularly through cross-correlation with galaxy surveys, as independent probes of the Hubble constant.

"Canadian-Chilean array for radio transient studies (CHARTS)"

Tomás Cassanelli is an astronomer and assistant professor specializing in astronomical instrumentation at Universidad de Chile. He holds a PhD in Astronomy & Astrophysics from the University of Toronto, where he focused on fast radio burst (FRB) localization at the time of detection using very-long-baseline interferometry (VLBI). His research spans radio astronomy, including analog and digital components, as well as fast optical astronomy with fast photon counters. Tomás' scientific interests lie in the rapidly varying transient sky such as pulsars, FRBs, and long period transients, and interferometric methods across radio to optical wavelengths.

"Mapping Alien Worlds: from Infernal to Habitable Worlds"

Lisa Dang is an Assistant Professor in the Physics and Astronomy Department of the University of Waterloo. She uses various telescopes, including the James Webb Space Telescope, to study the diversity of exoplanets and their climates. Her work involves mapping atmospheric temperature structures and constituents of exoplanets, with a particular focus on lava worlds. She also has experience in planetary microlensing and is involved with the Ariel Mission conduct population-level analysis of exoplanet atmospheres. Previously, she was a Banting Postdoctoral Fellow at the Institute for Research on Exoplanets (iREx) at the University of Montreal, specializing in exoplanet and exoplanetary atmosphere research. Lisa earned her PhD in physics from McGill University, where she also completed her undergraduate degree. During her graduate studies, she held a visiting research fellowship at Caltech/IPAC to work on the Spitzer Microlensing Campaign.

"Better together: insights and tools for joint analyses of clustering and lensing in cosmology"

Antón is a cosmologist and BCCP postdoctoral fellow at UC Berkeley and LBNL. His research lies at the interface of CMB and large-scale structure, combining theoretical work with data analysis of to try to understand what drove the accelerated expansion of the Universe at the earliest and most recent of times. He is heavily involved in the DESI and Simons Observatory collaborations, with a focus on developing and exploting synergies between the two.

"2, 3, 4 point functions: GPU, some math, some data"

Zack Slepian is currently a tenured associate professor in the astronomy department at the University of Florida, and previous to that held Einstein and Chamberlain fellowships at Lawrence Berkeley National Laboratory after a PhD at Harvard with Daniel Eisenstein. His major focus has been measuring and using higher-order clustering statistics of galaxies in redshift surveys such as BOSS, DESI and Roman, including the first detection of Baryon Acoustic Oscillations in the galaxy 3-point function, and intriguing evidence for parity violation in the galaxy 4-point function

"Probing Gravity on Cosmological Scales: Theories and Parametrizations"

Carola Zanoletti is a PhD student in cosmology at Newcastle University. She is testing models that modify the background expansion and growth of structure in the universe. She received her master's degree at the University of Cambridge, studying discretization conditions on the perturbation equations for a palindromic universe model at the Institute of Astronomy

"The separate universe approach in multifield inflation models"

Hugo Holland is a second year PhD student in Institut d'Astrophysique Spatiale in Orsay (just south of Paris). He works with Julien Grain on stochastic inflation and all things related. Before his PhD, Hugo graduated from Ecole Polytechnique in France and got his masters degree in theoretical physics at King's College London, where he worked on eternal inflation with Eleni Alexandra Kontou.

"Measuring and modelling galaxy intrinsic alignment"

Dr Danielle Leonard is a Lecturer at the School of Mathematics, Statistics and Physics at Newcastle University. Their research focuses on late-time observational cosmology, particularly weak lensing and photometric galaxy clustering. They work both on understanding systematic effects which impact weak gravitational lensing measurements such as intrinsic alignment and photometric redshift uncertainties, and on methods for best constraining beyond-standard cosmological models with observational data.