Alar Toomre

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Alar Toomre is an Estonian born astronomer and mathematician who immigrated to the United States in 1949.[1][2] He is a professor of applied mathematics at the Massachusetts Institute of Technology.[3] Toomre's research is focused on the dynamics of galaxies.

Contents

[edit] Career

Toomre received an undergraduate degree in Aeronautical Engineering and Physics from MIT in 1957[2][4] and then studied at the University of Manchester on a Marshall Scholarship where he obtained a Ph.D. in Fluid Dynamics.[5][6]

Toomre returned to MIT to teach after completing his Ph.D. and remained there for two years.[5] After spending a year at Princeton University, he returned again to MIT as part of the faculty, where he stayed.[5] Toomre was appointed an Associate Professor of Mathematics at MIT in 1965.[7]

[edit] Scientific Accomplishments

The results of the Toomre brothers' simulations of the Antennae Galaxies
The results of the Toomre brothers' simulations of the Antennae Galaxies

In 1964 Toomre devised an instability criterion for differentially rotating disks now known as the Toomre Instability.[8] Alternatively, it may be expressed as Toomre's Stability Criterion which is usually measured with the parameter Q.[9]

Toomre collaborated with Peter Goldreich in 1969 on the subject of polar wander, developing the theory of polar wander.[10] Whether true polar wander has been observed on earth, or apparent polar wander is accountable for all the observations of paleomagnetism remains a controversial issue.[11]

The Antennae Galaxies by Brad Whitmore (STScI), and NASA
The Antennae Galaxies by Brad Whitmore (STScI), and NASA

Toomre conducted the first computer simulations of galaxy mergers in the 1970s with his brother Juri Toomre.[12][13] Although the small number of particles in the simulations obscured many processes in galactic collisions, Toomre and Toomre were able to identify tidal tails in his simulations, similar to those seen in the Antennae galaxies and The Mice.[14][15][16] The brothers attempted to reproduce specific galaxy mergers in their simulations, and it was their reproduction of the Antennae galaxies that gave them the greatest pleasure.[17] In 1977 Toomre suggested that elliptical galaxies are the remnants of the major mergers of spiral galaxies.[18][19] He further showed that based on the local galaxy merger rate, over a Hubble time the observed number of elliptical galaxies are produced if the universe begins with only spiral galaxies.[20] This idea remained controversial and widely debated for some time.[21][22]

From this work, the Toomre brothers identified the process of collision evolution as the Toomre sequence.[23][24] The sequence begins with two well separated spiral galaxies and follows them through collisional disruption until they settle into a single elliptical galaxy.[25]

[edit] Awards and Honors

In 1993, Toomre received the Dirk Brouwer Award which recognizes "outstanding contributions to the field of Dynamical Astronomy".[26][27]

Toomre was one of the 1984 recipients of the MacArthur Fellowship, popularly known as the "Genius Grant".[1][28]

[edit] References

  1. ^ a b The John D. and Catherine T. MacArthur Foundation. MacArthur Fellows November 1984. Retrieved on 2007-05-18.
  2. ^ a b David B. Oberman. "Toomre Awarded MacArthur Grant", The Tech, November 16, 1984, p. 1. Retrieved on 2007-05-18. 
  3. ^ SDSC SIMULATION SHOWS COLLISION WITH ANDROMEDA. HPC Wire (December 5, 2000).
  4. ^ Dormcon Prexy Vote Thursday Joe Bowers '57 Only Candidate. The Tech (February 26, 1956). Retrieved on 2007-05-18.
  5. ^ a b c "Alar Toomre, Course XVI Senior, To Receive Marshall Scholarship", April 9, 1957, p. 6. Retrieved on 2007-05-18. 
  6. ^ "Toomre Receives MacArthur Award", The Tech, November 16, 1984, p. 22. Retrieved on 2007-05-18. 
  7. ^ "Fifty-eight faculty promoted", The Tech, April 14, 1965, p. 3. Retrieved on 2007-05-18. 
  8. ^ Tim Palucka. Star Maker Machinery. HPC wire. Retrieved on 2007-05-18.
  9. ^ James Binney and Scott Tremaine [1987] (1994). in Jeremiah Ostriker: Galactic Dynamics (in English). Princeton, New Jersey: Princeton University Press, 363. ISBN 0-691-08445-9. 
  10. ^ Richard A. Kerr (January 21, 2000). "Did the Dinosaurs Live on a Topsy-Turvy Earth?". Science 287: 406–407. doi:10.1126/science.287.5452.406. 
  11. ^ V. Courtillot (Fall Meeting 2004). A Short Review of True Polar Wander. American Geophysical Union. Retrieved on 2007-05-18. abstract #U31B-08
  12. ^ Toomre and the first models. Science Notes University of Santa Cruz (Summer 1997). Retrieved on 2007-05-18.
  13. ^ Karen Hartley (April 8, 1989). Mixing it up in space: astronomers debate the role mergers play in galaxy formation. Science News. Retrieved on 2007-05-18.
  14. ^ Hubble Reveals Stellar Fireworks Accompanying Galaxy Collisions. Space Telescope Science Institute (October 21, 1997). Retrieved on 2007-05-18.
  15. ^ The Mice at Play. National Radio Astronomy Observatory (May 1, 2002).
  16. ^ Michael Shara (February 2000). Cannibals of the Cosmos - much more has become known about galaxies, since Edwin Hubble confirmed their existence in 1925. Natural History. Retrieved on 2007-05-18.
  17. ^ Alar Toomre and Juri Toomre (1972). "Galactic Tails and Bridges". The Astrophysical Journal 178: 623–666. doi:10.1086/151823. 
  18. ^ Merger Remnants and Elliptical Galaxies.
  19. ^ Peering Far Back in Time to Uncover the Secrets of Galaxy Evolution. European Space Agency (December 1, 1992). Retrieved on 2007-05-18.
  20. ^ Michael J. West (December 1997). THE GALAXY-CLUSTER-SUPERCLUSTER CONNECTION. Canadian Astronomical Society/Société Canadienne D'Astronomie Cassiopeia No. 95.
  21. ^ Robert Joseph (Fall 2004). Merging Spiral Galaxies Create Ellipticals. Nã Kilo Hõkũ. Retrieved on 2007-05-18.
  22. ^ Curtis Struck (1999). Galaxy Collisions 1-137. Physics Reports. Retrieved on 2007-05-18.
  23. ^ Toomre Sequence. Cosmos: The Swinburne Astronomy Online Encyclopedia. Retrieved on 2007-05-18.
  24. ^ Laine, S.; van der Marel, R. P.; Böker, T.; Mihos, J. C.; Hibbard, J. E.; Zabludoff, A. I. (2000). "HST Observations of the Nuclear Regions of the Toomre Sequence of Merging Galaxies". The Central Kiloparsec of Starbursts and AGN: The La Palma Connection, ASP Conference Proceedings 249: 179. 
  25. ^ W. van Driel - Yu Gao - D. Monnier-Ragaigne (2001). "HI line observations of luminous infrared galaxy mergers". Astronomy and Astrophysics 368: 64–73. doi:10.1051/0004-6361:20000509. 
  26. ^ AAS Division on Dynamical Astronomy Newsletter 75. American Astronomical Society Division on Dynamical Astronomy (October 1993). Retrieved on 2007-05-18.
  27. ^ The DDA/AAS Brouwer Award. American Astronomical Society/Division on Dynamical Astronomy. Retrieved on 2007-05-18.
  28. ^ Elizabeth A. Thomson (September 28, 2004). MacArthur 'genius' grants go to four from MIT. MIT news office. Retrieved on 2007-05-18.