Avishai Dekel | |
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| Born | 13 January 1951  Jerusalem |
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| Website | http://www.phys.huji.ac.il/~dekel |
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| Fields | Cosmology, astrophysics |
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Avishai Dekel (born 1951) is a professor of physics at the Hebrew University of Jerusalem, Israel, holding the Andre Aisenstadt Chair of Theoretical Physics. His primary research interests are in astrophysics and cosmology.
Dekel earned his Ph.D. from the Hebrew University in 1980, and was a research fellow at Caltech and assistant professor at Yale University before joining the faculty of the Hebrew University in 1986.
He served as the Head of The Racah Institute of Physics (1997–2001), the Dean of the Authority for the Community and Youth at the Hebrew University (2005–2011), and the President of the Israel Physical Society (2008–11). He headed the university computing committee, was a member of the executive committee of the board of trustees and a member of the standing committee of the Hebrew University.
Dekel was awarded a Visiting Miller Professorship [1] at UC Berkeley, a Blaise Pascal International Chair of Research by the École Normale Supérieure in Paris (2004–06), and a Lagrange fellowship in IAP Paris (2015–16). He has been elected as a fellow of the Israel Physical Society (2019), and has been awarded the Landau Prize for Arts and Sciences (2020).
Dekel is known for his contributions to research in cosmology, especially the study of the formation of galaxies and large-scale structure in the Universe, which is dominated by dark energy and dark matter. [2] [3] His expertise is dwarf galaxies and supernova feedback (1986, 2003), large-scale cosmic flows and early estimates of fundamental cosmological parameters (1989-2001), [4] the structure of dark-matter galactic halos (2000–2003), and the theory of galaxy formation (2003–2012). [5] [6]
His research focuses on galaxy formation in its most active phase at the early universe, using analytic models and computer simulations. He studies how continuous streams of cold gas and merging galaxies from the cosmic web lead to star-forming disks and drive violent gravitational disk instability, and how this instability leads to the formation of compact spheroidal galactic components with central massive black holes. His recent work focuses on the formation of the first galaxies as observed by the James Webb Space Telescope, proposing a unique phase of feedback-free starbursts in the early Universe.
Dekel is the most highly cited astrophysicist in Israel, with 60,000 citations and H-index 120.
In astronomy, dark matter is a hypothetical form of matter that appears not to interact with light or the electromagnetic field. Dark matter is implied by gravitational effects which cannot be explained by general relativity unless more matter is present than can be seen. Such effects occur in the context of formation and evolution of galaxies, gravitational lensing, the observable universe's current structure, mass position in galactic collisions, the motion of galaxies within galaxy clusters, and cosmic microwave background anisotropies.
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.
Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroids, asteroids, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere. Cosmology is a branch of astronomy that studies the universe as a whole.
Plasma cosmology is a non-standard cosmology whose central postulate is that the dynamics of ionized gases and plasmas play important, if not dominant, roles in the physics of the universe at interstellar and intergalactic scales. In contrast, the current observations and models of cosmologists and astrophysicists explain the formation, development, and evolution of large-scale structures as dominated by gravity.
In physical cosmology, structure formation describes the creation of galaxies, galaxy clusters, and larger structures starting from small fluctuations in mass density resulting from processes that created matter. The universe, as is now known from observations of the cosmic microwave background radiation, began in a hot, dense, nearly uniform state approximately 13.8 billion years ago. However, looking at the night sky today, structures on all scales can be seen, from stars and planets to galaxies. On even larger scales, galaxy clusters and sheet-like structures of galaxies are separated by enormous voids containing few galaxies. Structure formation models gravitational instability of small ripples in mass density to predict these shapes, confirming the consistency of the physical model.
Fred C. Adams is an American astrophysicist who has made contributions to the study of physical cosmology.
Carlos Silvestre Frenk is a Mexican-British cosmologist. Frenk graduated from the National Autonomous University of Mexico and the University of Cambridge and spent his early research career in the United States, before settling permanently in the United Kingdom. He joined the Durham University Department of Physics in 1986 and since 2001 has served as the Ogden Professor of Fundamental Physics at Durham University.
Astroparticle physics, also called particle astrophysics, is a branch of particle physics that studies elementary particles of astrophysical origin and their relation to astrophysics and cosmology. It is a relatively new field of research emerging at the intersection of particle physics, astronomy, astrophysics, detector physics, relativity, solid state physics, and cosmology. Partly motivated by the discovery of neutrino oscillation, the field has undergone rapid development, both theoretically and experimentally, since the early 2000s.
Geraint Francis Lewis, FLSW is a Welsh astrophysicist, who is best known for his work on dark energy, gravitational lensing and galactic cannibalism. Lewis is a Professor of Astrophysics at the Sydney Institute for Astronomy, part of the University of Sydney's School of Physics. He is head of the Gravitational Astrophysics Group. He was previously the Associate Head for Research at the School of Physics, and held an Australian Research Council Future Fellowship between 2011 and 2015. Lewis won the 2016 Walter Boas Medal in recognition of excellence in research in Physics. In 2021, he was awarded the David Allen Prize of the Astronomical Society of Australia for exceptional achievement in astronomy communication.
George Petros Efstathiou is a British astrophysicist who is Professor of Astrophysics (1909) at the University of Cambridge and was the first Director of the Kavli Institute for Cosmology at the University of Cambridge from 2008 to 2016. He was previously Savilian Professor of Astronomy at the University of Oxford.
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Pavel Kroupa is a Czech-Australian astrophysicist and professor at the University of Bonn.
Tsvi Piran is an Israeli theoretical physicist and astrophysicist, best known for his work on Gamma-ray Bursts (GRBs) and on numerical relativity. The recipient of the 2019 EMET prize award in Physics and Space Research.
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The UniverseMachine is a project carrying out astrophysical supercomputer simulations of various models of possible universes, created by astronomer Peter Behroozi and his research team at the Steward Observatory and the University of Arizona. Numerous universes with different physical characteristics may be simulated in order to develop insights into the possible beginning and evolution of our universe. A major objective is to better understand the role of dark matter in the development of the universe. According to Behroozi, "On the computer, we can create many different universes and compare them to the actual one, and that lets us infer which rules lead to the one we see."
Anastasia Fialkov is a Kazakhstan-born Israeli theoretical astrophysicist, currently a professor in the Institute of Astronomy of the University of Cambridge, England, and a senior research fellow of Magdalene College, Cambridge.
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