Lars Hernquist

Last updated

Lars Eric Hernquist
NationalityAmerican
Alma mater California Institute of Technology
Known for Hernquist Profile
Illustris project
Awards Gruber Prize in Cosmology (2020)
Scientific career
Fields Astrophysics
Institutions Harvard University
Center for Astrophysics | Harvard & Smithsonian
University of California, Santa Cruz
Thesis Thermal and Magnetic Properties of Neutron Stars  (1985)
Doctoral advisor Roger Blandford

Lars Hernquist (December 14, 1954) is a theoretical astrophysicist and Mallinckrodt Professor of Astrophysics at the Center for Astrophysics | Harvard & Smithsonian. He is best known for his research on dynamical processes in cosmology and galaxy formation/galaxy evolution. [1] [2] [3] [4]

Contents

Career and research

Hernquist's research involves the dynamics of galaxies and the effect of a merger driven model for galaxy evolution. He is a world expert in simulating mergers of galaxies to demonstrate the expected appearance and morphology of the resulting body. He defined the "Hernquist Profile", which is an analytic expression for the distribution of dark matter in galaxies. [5] Hernquist's research is largely computational with one of the world's largest supercomputers accessible for his research. [6]

Awards

Hernquist was awarded the 2020 Gruber Prize in Cosmology jointly with Volker Springel, who together have made computer simulations "an indispensable tool for cosmologists, allowing them to test theories and locate fertile areas for further research." [7]

Related Research Articles

The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies. Galaxy formation is hypothesized to occur from structure formation theories, as a result of tiny quantum fluctuations in the aftermath of the Big Bang. The simplest model in general agreement with observed phenomena is the Lambda-CDM model—that is, that clustering and merging allows galaxies to accumulate mass, determining both their shape and structure. Hydrodynamics simulation, which simulates both baryons and dark matter, is widely used to study galaxy formation and evolution.

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<span class="mw-page-title-main">Plasma cosmology</span> Non-standard model of the universe; emphasizes the role of ionized gases

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<span class="mw-page-title-main">Astrophysics</span> Subfield of astronomy

Astrophysics is a science that employs the methods and principles of physics and chemistry in the study of astronomical objects and phenomena. As one of the founders of the discipline, James Keeler, said, Astrophysics "seeks to ascertain the nature of the heavenly bodies, rather than their positions or motions in space–what they are, rather than where they are." Among the subjects studied are the Sun, other stars, galaxies, extrasolar planets, the interstellar medium and the cosmic microwave background. Emissions from these objects are examined across all parts of the electromagnetic spectrum, and the properties examined include luminosity, density, temperature, and chemical composition. Because astrophysics is a very broad subject, astrophysicists apply concepts and methods from many disciplines of physics, including classical mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.

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<span class="mw-page-title-main">Dark matter halo</span> Theoretical cosmological structure

According to modern models of physical cosmology, a dark matter halo is a basic unit of cosmological structure. It is a hypothetical region that has decoupled from cosmic expansion and contains gravitationally bound matter. A single dark matter halo may contain multiple virialized clumps of dark matter bound together by gravity, known as subhalos. Modern cosmological models, such as ΛCDM, propose that dark matter halos and subhalos may contain galaxies. The dark matter halo of a galaxy envelops the galactic disc and extends well beyond the edge of the visible galaxy. Thought to consist of dark matter, halos have not been observed directly. Their existence is inferred through observations of their effects on the motions of stars and gas in galaxies and gravitational lensing. Dark matter halos play a key role in current models of galaxy formation and evolution. Theories that attempt to explain the nature of dark matter halos with varying degrees of success include cold dark matter (CDM), warm dark matter, and massive compact halo objects (MACHOs).

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<span class="mw-page-title-main">GADGET</span> Computer software for cosmological simulations

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The Illustris project is an ongoing series of astrophysical simulations run by an international collaboration of scientists. The aim was to study the processes of galaxy formation and evolution in the universe with a comprehensive physical model. Early results were described in a number of publications following widespread press coverage. The project publicly released all data produced by the simulations in April, 2015. Key developers of the Illustris simulation have been Volker Springel and Mark Vogelsberger. The Illustris simulation framework and galaxy formation model has been used for a wide range of spin-off projects, starting with Auriga and IllustrisTNG followed by Thesan (2021), MillenniumTNG (2022) and TNG-Cluster.

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References

  1. Chown, Marcus (June 1, 1996). "Science : Tadpole galaxies are lightweights". New Scientist . Retrieved November 26, 2023.
  2. "Astrophysicist Maps Out Our New Galaxy". ScienceDaily. Retrieved May 6, 2020.
  3. "Simulations Show How Growing Black Holes Regulate Galaxy Formation". ScienceDaily. Retrieved May 6, 2020.
  4. "Magellanic Clouds Are First-Time Visitors". ScienceDaily. Retrieved May 6, 2020.
  5. Hernquist, Lars (June 1990). "An Analytical Model for Spherical Galaxies and Bulges". Astrophysical Journal. 356: 359. Bibcode:1990ApJ...356..359H. doi: 10.1086/168845 . ISSN   0004-637X.
  6. "Odyssey - PowerEdge M600 Cluster, Xeon E5410 2.3Ghz, Infiniband". www.top500.org. Retrieved May 6, 2020.
  7. "2020 Gruber Cosmology Prize". gruber.yale.edu. Retrieved May 6, 2020.