Risa Wechsler

About

Risa Wechsler is the Humanities and Sciences Professor and the Director of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University. She is also a Professor of Physics and of Particle Physics and Astrophysics, and serves as the Director of the Center for Decoding the Universe, as well as an Associate Director at Stanford Data Science. Her research as a cosmologist investigates fundamental questions about the universe, including its formation, composition, structure, and future. She focuses on understanding the evolution of galaxies, the large-scale structure of the universe, and the nature of dark matter and dark energy. Her work employs large numerical simulations, theoretical models, and the analysis of extensive observational data to explore these cosmic forces. Recent research includes studying the formation and cosmological context of the Milky Way, probing dark matter through small-scale cosmic structures, and integrating data science and AI/ML techniques to advance understanding. Wechsler has played significant leadership roles in major international collaborations such as the Dark Energy Survey, Dark Energy Spectroscopic Instrument, and the Rubin Observatory's Legacy Survey of Space and Time. She is actively involved in the Via Survey, which aims to map the Milky Way with high precision to investigate dark matter physics. She holds memberships in the National Academy of Sciences and the American Academy of Arts and Sciences, and is a Fellow…

Research topics

• Astronomy
• Physics
• Astrophysics
• Computer Science
• Optics
• Engineering
• Quantum mechanics
• Particle physics
• Geography
• Psychology

Selected publications

• Multi-messenger Observations of a Binary Neutron Star Merger

  2017 · 1398 citations

  On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg² at a luminosity distance of 40₋₈⁺⁸ Mpc a…

  DOI

• Dark Energy Survey Year 3 results: Cosmological constraints from galaxy clustering and weak lensing

  Physical review. D/Physical review. D. · 2022 · 1090 citations

  Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM

  DOI

• DESI 2024 VI: cosmological constraints from the measurements of baryon acoustic oscillations

  arXiv (Cornell University) · 2025 · 897 citations

  Abstract We present cosmological results from the measurement of baryon acoustic oscillations (BAO) in galaxy, quasar and Lyman- α forest tracers from the first year of observations from the Dark Energy Spectroscopic Instrument (DESI), to be released in the DESI Data Release 1. DESI BAO provide robust measurements of the transverse comoving distance and Hubble rate, or their combination, relative to the sound horizon, in seven redshift bins from over 6 million extragalactic objects in the redshi…

  Publisher

• Dark Energy Survey Year 3 results: Cosmology from cosmic shear and robustness to data calibration

  Physical review. D/Physical review. D. · 2022 · 416 citations

  This work, together with its companion paper, Secco, Samuroff et al. [Phys. Rev. D 105, 023515 (2022)], present the Dark Energy Survey Year 3 cosmic-shear measurements and cosmological constraints based on an analysis of over 100 million source galaxies. With the data spanning $4143\text{ }\text{ }{\mathrm{deg}}^{2}$ on the sky, divided into four redshift bins, we produce a measurement with a signal-to-noise of 40. We conduct a blind analysis in the context of the Lambda-Cold Dark Matter ($\math…

  DOI

• Overview of the Instrumentation for the Dark Energy Spectroscopic Instrument

  The Astronomical Journal · 2022 · 402 citations

  Abstract The Dark Energy Spectroscopic Instrument (DESI) embarked on an ambitious 5 yr survey in 2021 May to explore the nature of dark energy with spectroscopic measurements of 40 million galaxies and quasars. DESI will determine precise redshifts and employ the baryon acoustic oscillation method to measure distances from the nearby universe to beyond redshift z > 3.5, and employ redshift space distortions to measure the growth of structure and probe potential modifications to general relati…

  DOI

Recent grants

• Reionization, Environment, and the Galaxy Content of Milky-Way Mass Halos

  NSF · $329k · 2009–2013

• Collaborative Research: Searching for Dark Matter Subhalos in Distant Strong Gravitational Lenses

  NSF · $323k · 2017–2021

• Collaborative Research: The SAGA Project: Searching for Dwarf Galaxies Around Milky Way Analogs

  NSF · $291k · 2015–2020

Frequent coauthors

• D. Gruen

  990 shared

• L. N. da Costa

  Laboratório Interinstitucional de e-Astronomia

  940 shared

• A. Carnero Rosell

  936 shared

• E. Bertin

  Orange (France)

  809 shared

• R. Miquel

  Institute for High Energy Physics

  775 shared

• E. S. Rykoff

  765 shared

• A. Roodman

  SLAC National Accelerator Laboratory

  680 shared

• R. L. C. Ogando

  National Observatory

  668 shared

Education

• PhD, Physics

  University of California Santa Cruz

  2001

• S.B., Physics Department

  Massachusetts Institute of Technology

  1996

Awards & honors

• Elected member of the National Academy of Sciences
• Elected member of the American Academy of Arts and Sciences
• Fellow of the American Physical Society
• Fellow of the American Association for the Advancement of Sc…

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• Persis S. Drellh-190
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