معرفی
David J. Helfand is a Professor in the Department of Astronomy at Columbia University, serving as Chair (1992–present) and Co-Director of the Columbia Astrophysics Laboratory (1994–present). He has held visiting roles at Cambridge University and the Danish Space Research Institute. His research focuses on radio surveys (e.g., FIRST and MAGPIS), neutron stars, supernova remnants, and the cosmic X-ray background. He has pioneered large-scale radio surveys to study galactic and extragalactic structures, weak gravitational lensing, and high-redshift quasars. Helfand holds a Ph.D. in Astronomy from the University of Massachusetts (1977) and an A.B. in Physics from Amherst College (1973). He co-founded Quest University Canada in 2005 and became its President in 2008.
Education:
- Ph.D. Astronomy, University of Massachusetts, 1977
- M.S. Physics, University of Massachusetts, 1977
- A.B. Physics (Independent Scholar), Amherst College, 1973
Research Interests:
Helfand's work emphasizes radio surveys like FIRST (mapping 9200 square degrees of the sky) and MAGPIS (Galactic Plane imaging). He studies neutron stars' evolution, supernova remnants (e.g., Vela and 3C58), and contributions of starburst galaxies/AGN to the cosmic X-ray background. He employs Chandra/XMM-Newton observations to probe obscured quasars and high-redshift clusters.
Grants & Collaborations:
Leadership roles include founding Quest University Canada and directing Columbia's astronomy department. His surveys have identified thousands of radio sources, enabled optical identifications, and explored cosmological structures via radio source correlations and lensing.
Labs/Teams:
Helfand collaborates with the Columbia Astrophysics Laboratory and international teams using facilities like the VLA, Chandra, and XMM-Newton. Projects include the MSX mid-IR survey and searches for obscured quasars and gravitational lenses.
