Avishai Dekel

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Avishai Dekel
Avishai office24 s.jpg
Born13 January 1951  OOjs UI icon edit-ltr-progressive.svg
Jerusalem   OOjs UI icon edit-ltr-progressive.svg
Alma mater
Occupation
Website http://www.phys.huji.ac.il/~dekel   OOjs UI icon edit-ltr-progressive.svg
Academic career
Fields Cosmology, astrophysics   OOjs UI icon edit-ltr-progressive.svg
Institutions
Cold streams from the cosmic web feeding a galaxy in the early universe, based on a hydro-cosmological computer simulation (Dekel et al., 2011) The picture shows gas density, extending to a half a million light years, when the Universe was 3 billion years old. Bird 314 medres.png
Cold streams from the cosmic web feeding a galaxy in the early universe, based on a hydro-cosmological computer simulation (Dekel et al., 2011) The picture shows gas density, extending to a half a million light years, when the Universe was 3 billion years old.
Violent gravitational Instability in a disk galaxy in the early universe, based on a hydro-cosmological computer simulation (Dekel et al., 2011) The picture of gas density shows that the disk is fragmented to giant clumps where stars form. The disk radius is 30,000 light years. Dekel photograph.png
Violent gravitational Instability in a disk galaxy in the early universe, based on a hydro-cosmological computer simulation (Dekel et al., 2011) The picture of gas density shows that the disk is fragmented to giant clumps where stars form. The disk radius is 30,000 light years.

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.

Contents

Academic career

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.

Dekel is the most highly cited astrophysicist in Israel, with 45,000 citations and H-index 106.

Related Research Articles

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.

A non-standard cosmology is any physical cosmological model of the universe that was, or still is, proposed as an alternative to the then-current standard model of cosmology. The term non-standard is applied to any theory that does not conform to the scientific consensus. Because the term depends on the prevailing consensus, the meaning of the term changes over time. For example, hot dark matter would not have been considered non-standard in 1990, but would be in 2010. Conversely, a non-zero cosmological constant resulting in an accelerating universe would have been considered non-standard in 1990, but is part of the standard cosmology in 2010.

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References

  1. "Miller Institute - Visiting Professorship list". miller.berkeley.edu. Retrieved 2016-10-21.
  2. Alan P. Lightman (1993), Ancient Light: Our Changing View of the Universe, Harvard University Press, p. 134, ISBN   978-0-674-03363-4
  3. M. S. Longair (2006), The cosmic century: a history of astrophysics and cosmology, Cambridge University Press, p.  360, ISBN   978-0-521-47436-8
  4. "More evidence for the accelerating universe", Physics World, Institute of Physics, 17 September 1999, retrieved 12 December 2012
  5. Eric Hand (1 April 2009), "Early galaxies surprise with size", Nature News, doi:10.1038/news.2009.225
  6. Rachel Courtland (21 January 2009), "Dark matter filaments stoked star birth in early galaxies", New Scientist, retrieved 12 December 2012