Faculty | Haldan N. Cohn

Professor
Ph.D., Astrophysics, Princeton University, 1979.

Contact Information:

Astronomy Department
Indiana University
Swain West 411
727 East Third Street
Bloomington, IN 47405
Phone: (812) 855-4174
Fax: (812) 855-8725
Email: cohn [at] astro.indiana.edu

Biographical Information:

Professor Haldan Cohn has been on the IU Astronomy faculty since 1983. He received an A.B. in Physics from Harvard University in 1975 and a Ph.D. in Astrophysical Sciences from Princeton University in 1979.  Professor Cohn held postdoctoral positions at the Harvard-Smithsonian Center for Astrophysics, the California Institute of Technology, and the University of Illinois before coming to IU.  The courses that he typically teaches include A100 (Introduction to the Solar System), A105 (Stars and Galaxies), A451 (Introduction to Astrophysics), and A570 (Galactic Dynamics).

Research Interests:

Professor Cohn's research centers on the dynamics of stellar systems, including interacting binary stars, star clusters, the Milky Way Galaxy, galactic nuclei, and clusters of galaxies.  Professors Haldan Cohn and Phyllis Lugger  lead a research program in these areas which includes both theoretical and observational components.  The theoretical studies use high-performance computers at IU, including a recently acquired GRAPE-6 N-body supercomputer. The observational studies make substantial use of the WIYN telescope, the Hubble Space Telescope, and the Chandra X-ray Observatory.

Their principal research collaborators include Josh Grindlay (Harvard University), Charles Bailyn and Gordon Drukier (Yale University), Adrienne Cool (San Francisco State University), and Brian Murphy (Butler University).  Former Ph.D. students include Larry David (Harvard-Smithsonian Center for Astrophysics), Brian Murphy, Steve Cederbloom (Mount Union College), Robert Grabhorn, Paul Bode (Princeton University), Jim Dull (Albertson College of Idaho),  Bob Berrington (University of Wyoming), Shawn Slavin (Purdue-Calmet) and Allen Rogel (Bowling Green State).

Following are some of our current research projects.

• The ChaMPlane Survey: Identification of Chandra X-ray sources in the Galactic plane using WIYN
• Detection and Identification of Chandra X-ray sources in the collapsed-core globular cluster M30
• Analysis of the Chandra X-ray source spatial distributions in normal and collapsed-core globular clusters
• Simulation of star cluster evolution with the GRAPE-6 N-body Supercomputer at Indiana University
• Study of the global dynamics of globular clusters using WIYN

Selected Publications

• Chandra X-Ray Sources in the Collapsed-Core Globular Cluster M30 (NGC 7099)
  Lugger, P. M., Cohn, H. N., Heinke, C. O., Grindlay, J. E., & Edmonds, P. D. 2007, ApJ, 657, 286.
• The Global Kinematics of the Globular Cluster M92
  Drukier, G. A., Cohn, H. N., Lugger, P. M., Slavin, S. D., Berrington, R. C., & Murphy, B. W. 2007, AJ, 133, 1041.
• Faint X-Ray Sources in the Globular Cluster Terzan 5
  Heinke, C. O., Wijnands, R., Cohn, H. N., Lugger, P. M., Grindlay, J. E., Pooley, D., & Lewin, W. H. G. 2006, ApJ, 651, 1098.
• ChaMPlane Discovery of Candidate Symbiotic Binaries in Baade's and Stanek's Windows
  van den Berg, M., Grindlay, J., Laycock, S., Hong, J., Zhao, P., Koenig, X., Schlegel, E. M., Cohn, H., Lugger, P., Rich, R. M., Dupree, A. K., Smith, G. H., & Strader, J. 2006, ApJ, 647, L135.
• Three Years of ChaMPlane Northern Field WIYN Spectroscopy
  Rogel, A. B., Lugger, P. M., Cohn, H. N., Slavin, S. D., Grindlay, J. E., Zhao, P., & Hong, J. 2006, ApJS, 163, 160.
• Chandra Multiwavelength Plane (ChaMPlane) Survey: An Introduction
  Grindlay, J. E., Hong, J., Zhao, P., Laycock, S., van den Berg, M., Koenig, X., Schlegel, E. M., Cohn, H. N., Lugger, P. M., & Rogel, A. B. 2005, ApJ, 635, 920.
• A Deep Chandra Survey of the Globular Cluster 47 Tucanae: Catalog of Point Sources
  Heinke, C. O., Grindlay, J. E., Edmonds, P. D., Cohn, H. N., Lugger, P. M., Camilo, F., Bogdanov, S., & Freire, P. C. 2005, ApJ, 625, 796.
  
• Anisotropic Fokker-Planck Models for the Evolution of Globular Star Clusters: The Core-Halo Connection
  Drukier, G. A., Cohn, H. N., Lugger, P. M., Yong, H. 1999, ApJ, 518, 233.