Alar Toomre Explained

Alar Toomre
Birth Date:5 February 1937
Birth Place:Rakvere, Estonia
Workplaces:Massachusetts Institute of Technology
Institute for Advanced Study
Alma Mater:Massachusetts Institute of Technology
University of Manchester

Alar Toomre (born 5 February 1937, in Rakvere) is an American astronomer and mathematician.[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. He is a 1984 MacArthur Fellow.

Career

Following the Soviet occupation of Estonia in 1944, Toomre and his family fled to Germany; they emigrated to the United States in 1949. He received an undergraduate degree in Aeronautical Engineering and Physics from MIT in 1957[4] and then studied at the University of Manchester on a Marshall Scholarship where he obtained a Ph.D. in fluid mechanics.[5] [6]

Toomre returned to MIT to teach after completing his Ph.D. and remained there for two years. After spending a year at the Institute for Advanced Study, he returned again to MIT as part of the faculty, where he stayed. Toomre was appointed an Associate Professor of Mathematics at MIT in 1965, and Professor in 1970.[7]

Scientific accomplishments

In 1964, Toomre devised a local gravitational stability criterion for differentially rotating disks.[8] It is known as the Toomre stability criterion, which is usually measured by a parameter denoted as Q.[9] The Q parameter measures the relativeimportance of vorticity and internal velocity dispersion (large values of which stabilise) versus the disk surface density (large values of which destabilise). The parameter is constructed so that Q<1 implies instability.

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]

Toomre conducted the first computer simulations of galaxy mergers in the 1970s with his brother Jüri, an astrophysicist and solar physicist.[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 (as for the Antennae) through collisional disruption until they settle into a single elliptical galaxy.[25]

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".[28]

Toomre was the recipient of the Magellanic Premium award in 2014 for his work in numerical galaxy simulations during the 1960s.[29] Two years later, he was elected to the American Philosophical Society.[30]

Notes and References

  1. Web site: MacArthur Fellows November 1984 . The John D. . Catherine T. MacArthur Foundation . amp . 2007-05-18 . dead . https://web.archive.org/web/20070929090737/http://www.macfound.org/site/c.lkLXJ8MQKrH/b.1142683/k.77C6/Fellows_List__November_1984.htm . 2007-09-29 .
  2. News: Toomre Awarded MacArthur Grant. The Tech. November 16, 1984. 2007-05-18. David B. Oberman. 1. 2016-03-04. https://web.archive.org/web/20160304025506/http://tech.mit.edu/archives/VOL_104/TECH_V104_S0792_P001.pdf. dead.
  3. Web site: SDSC SIMULATION SHOWS COLLISION WITH ANDROMEDA . HPC Wire . December 5, 2000 . dead . https://web.archive.org/web/20070928004555/http://www.hpcwire.com/hpc-bin/artread.pl?direction=Current&articlenumber=17668 . 2007-09-28 .
  4. News: Dormcon Prexy Vote Thursday Joe Bowers '57 Only Candidate. The Tech. February 26, 1956. 6. 2007-05-18. 2016-03-04. https://web.archive.org/web/20160304111343/http://tech.mit.edu/archives/VOL_076/TECH_V076_S0031_P006.pdf. dead.
  5. News: Alar Toomre, Course XVI Senior, To Receive Marshall Scholarship. April 9, 1957. 6. 2007-05-18. 2016-03-03. https://web.archive.org/web/20160303170114/http://tech.mit.edu/archives/VOL_077/TECH_V077_S0116_P006.pdf. dead.
  6. News: Toomre Receives MacArthur Award. The Tech. November 16, 1984. 22. 2007-05-18. 2016-03-03. https://web.archive.org/web/20160303211959/http://tech.mit.edu/archives/VOL_104/TECH_V104_S0817_P012.pdf. dead.
  7. Web site: MIT Faculty Home page. . 2011-01-16 . 2013-01-23 . https://web.archive.org/web/20130123174401/http://math.mit.edu/people/profile?pid=277 . dead .
  8. Web site: Star Maker Machinery . Tim Palucka . HPC wire . 2007-05-18 . dead . https://web.archive.org/web/20070928004206/http://www.hpcwire.com/hpc/853956.html . 2007-09-28 .
  9. Book: James Binney. James Binney. Scott Tremaine. Scott Tremaine. amp. Galactic Dynamics. 363. Princeton University Press. Jeremiah Ostriker. Jeremiah Ostriker. 1994. Princeton, New Jersey. 0-691-08445-9. 1987.
  10. Did the Dinosaurs Live on a Topsy-Turvy Earth?. Richard A. Kerr. Science. January 21, 2000. 406–407. 287. 10.1126/science.287.5452.406. 5452. 129200632.
  11. 2004AGUFM.U31B..08C. A Short Review of True Polar Wander. V. Courtillot . Fall 2004. 31. U31B–08. AGU Fall Meeting Abstracts. abstract #U31B-08
  12. Toomre and the first models. Science Notes University of Santa Cruz. Summer 1997. 2007-05-18.
  13. Mixing it up in space: astronomers debate the role mergers play in galaxy formation. Karen Hartley. Science News. April 8, 1989. 2007-05-18.
  14. Web site: Hubble Reveals Stellar Fireworks Accompanying Galaxy Collisions. October 21, 1997. Space Telescope Science Institute. 2007-05-18. https://web.archive.org/web/20070420221652/http://hubblesite.org/newscenter/archive/releases/1997/34/astrofile/. 20 April 2007 . live.
  15. Web site: The Mice at Play. National Radio Astronomy Observatory. May 1, 2002.
  16. Web site: Cannibals of the Cosmos - much more has become known about galaxies, since Edwin Hubble confirmed their existence in 1925. Natural History. Michael Shara. February 2000. 2007-05-18. 2011-06-16. https://web.archive.org/web/20110616023012/http://findarticles.com/p/articles/mi_m1134/is_1_109/ai_59210822/pg_2/. dead.
  17. 1972ApJ...178..623T. Galactic Tails and Bridges. Alar Toomre. Jüri Toomre. amp. The Astrophysical Journal. 1972. 623–666. 178. 10.1086/151823.
  18. Web site: Merger Remnants and Elliptical Galaxies. 2007-05-18. https://web.archive.org/web/20070711041838/http://burro.astr.cwru.edu/JavaLab/GalCrashWeb/ellipt.html. 2007-07-11. dead.
  19. Web site: Peering Far Back in Time to Uncover the Secrets of Galaxy Evolution. European Space Agency. December 1, 1992. 2007-05-18.
  20. Web site: THE GALAXY-CLUSTER-SUPERCLUSTER CONNECTION. Michael J. West. Canadian Astronomical Society/Société Canadienne D'Astronomie Cassiopeia. 95. December 1997.
  21. Web site: Merging Spiral Galaxies Create Ellipticals. Robert Joseph. Nã Kilo Hõkũ. 13. Fall 2004. 2007-05-18.
  22. astro-ph/9908269. Galaxy Collisions. Curtis Struck. 1999. 321. 1–3. 1–137. 1999PhR...321....1S . 10.1016/S0370-1573(99)00030-7. Physics Reports . 119369136.
  23. Web site: Toomre Sequence. Cosmos: The Swinburne Astronomy Online Encyclopedia. 2007-05-18.
  24. 2001ASPC..249..179L. HST Observations of the Nuclear Regions of the Toomre Sequence of Merging Galaxies. Laine, S.. van der Marel, R. P.. Böker, T.. Mihos, J. C.. Hibbard, J. E.. Zabludoff, A. I.. Ann Zabludoff . ASP Conference Proceedings. 249. 1-58381-089-7. 2000. 179. astro-ph/0106396.
  25. HI line observations of luminous infrared galaxy mergers . W. van Driel - Yu Gao - D. Monnier-Ragaigne . Astronomy and Astrophysics . 2001 . 368 . 1 . 64–73 . 2007-05-18 . 10.1051/0004-6361:20000509 . https://web.archive.org/web/20070927194211/http://www.aanda.org/index.php?option=com_base_ora&url=articles%2Faa%2Ffull%2F2001%2F10%2Faa10295%2Faa10295.html&access=standard&Itemid=81 . 2007-09-27 . 2001A&A...368...64V . astro-ph/0101003 . 7784821 . live .
  26. Web site: AAS Division on Dynamical Astronomy Newsletter 75. October 1993. 2007-05-18. American Astronomical Society Division on Dynamical Astronomy. https://web.archive.org/web/20070702120414/http://dda.harvard.edu/newsletters/ddanews75.html. 2 July 2007 . live.
  27. Web site: The DDA/AAS Brouwer Award. American Astronomical Society/Division on Dynamical Astronomy. 2007-05-18. https://web.archive.org/web/20070513012548/http://dda.harvard.edu/brouwer_award/index.html. 13 May 2007 . live.
  28. Web site: MacArthur 'genius' grants go to four from MIT. Elizabeth A. Thomson. September 28, 2004. MIT news office. 2007-05-18. 2013-09-28. https://web.archive.org/web/20130928034035/http://web.mit.edu/newsoffice/2004/macarthurs.html. dead.
  29. Web site: 2014 Autumn General Meeting. 2014. 2017-04-05. https://web.archive.org/web/20170213210403/https://amphilsoc.org/prizes/presentations/2014/Autumn-General-Meeting/Magellanic-Premium. 2017-02-13. dead.
  30. Web site: APS Member History. 2021-02-18. search.amphilsoc.org.

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