Farhad Yusef-Zadeh Professor

Professor Zadeh attended SUNY at Stony Brook for his undergraduate studies in Physics, then attended Columbia University for his PhD in Astronomy in 1986. He spent two years at NASA's Goddard Space Flight Center working as a National Research Council postdoctoral fellow before joining the faculty of the Department of Physics and Astronomy at Northwestern University in 1988. Farhad's main interest is to understand the physical processes that take place in the nucleus of our galaxy, the nature of supernova remnants interacting with molecular clouds, and star formation occurring in HII regions. The observation, analysis, and interpretation of the data is taken with radio telescopes and to a lesser extent with infrared, X-ray and optical telescopes.

The Galactic Center

The nucleus of our Galaxy is considered to be rich and complex in its phenomenology. The activities occurring there are the extreme ends of activities found in nuclei of active galaxies and the disk of the Galaxy. I have worked on many different aspects of the unique sources such as the massive black hole Sgr A* at the dynamical center of the Galaxy. Recently, I have concentrated on the X-ray study of the colliding winds in massive stellar clusters, the origin of X-ray gas in the nucleus of the Galaxy as well as the origin of magnetized radio filaments found within the inner few hundred light years of the Galaxy. A recent review of what is happening at the center of the Galaxy can be found in Science magazine.

Supernova Remnant Masers

The 1720-MHz transition of OH molecule has recently been recognized as the source of an important class of masers (i.e., microwave lasers), the so-called "Supernova Masers". These masers are produced when the expanding supernova remnants interact with molecular clouds. The interaction drives a shock wave into the molecular cloud, compressing and heating the gas, which cools by emitting in a variety of molecular and atomic transitions at infrared and millimeter wavelengths. A recent review of OH masers in the Galaxy can be found in Science magazine.

Star Formation

Molecular condensations associated with protostellar sources are found within evolved HII regions. This suggests that a new generation of massive star formation has been induced by the expansion of the HII regions. My interest is to study the region where the radiation field from bright stars and the protostellar jets interact with each other.

Teaching and Public Outreach

Imaging in Astronomy (Astronomy 130)

This new service course for non-majors draws upon real-world examples from my own research interests to illustrate how image analysis is used to extract information in astronomy. One of the objectives of this course is to communicate that astronomical images obtained in different wavelength bands can be used as a vehicle to gain a better understanding of the physical laws. This course is designed for undergraduate non-science majors interested in learning astronomy through the manipulation of astronomical images of celestial objects. The IT group developed nine web-based homework assignments which are given to students once a week during the quarter. These assignments are as follows:

  1. Jupiter
  2. The Milky Way Galaxy
  3. The Interstellar Extinction
  4. The Evolution of Stars
  5. Jets from Protostars
  6. The Expansion of Supernova
  7. Masers: Signposts of Cosmic Collision
  8. Motion of Stars around a massive Black Hole
  9. Radio Filaments at the Core of the Galaxy

Imaging and Imagining Space

A collaboration between Farhad Zadeh and Pamela Bannos, who is a photographer and who teaches at NU, resulted in an exhibition at the Block Gallery. The IT department developed a website in collaboration with us. To learn more about astronomical images visit http://spaceimages.northwestern.edu.

Public Lectures on the Web

I have embarked on an outreach program of public lectures that has featured diverse and interesting topics with broad appeal to students and the public. These public lectures are videotaped and can be viewed on NU's department of Physics and Astronomy website here

The topics of these lectures are as follows:

"Music of the Spheres"
Professor Arthur Schmidt

"Copenhagen and the German Atomic Bomb Project: Bending Perception to Wish"
Professor Irving Klotz

"What's Your Sign? Astrology, Astronomy, and Pseudoscience"
Professor Michael Faison

"The History of Physics: Paul Dirac -- A Beautiful Mind in the 20th Century"
Professor Laurie Brown

"Tsunami: The Ultimate Sea Waves, Long-range Vectors of Death and Destruction"
Professor Emile Okal

"Asteroids: Their History, their Impact on Earth and their Complex Geology"
Professor Mark S. Robinson

"The Birth and Death of Stars"
Professor Walter Lewin

Recent Work in the News

Selected Publications

  • J. W. Hewitt, F. Yusef-Zadeh, M. Wardle M, et al.
    Green Bank Telescope Observations of IC 443: The Nature of OH (1720 MHz) Masers and OH Absorption
    Astrophysical Journal 652, 1288 (2006)
  • F. Yusef-Zadeh, D. Roberts, M. Wardle, et al.
    Flaring Activity of Sagittarius A* at 43 and 22 GHz: Evidence for Expanding Hot Plasma
    Astrophysical Journal 650, 189 (2006)
  • M. P. Muno, C. Law, J. S. Clark, et al.
    Diffuse, Nonthermal X-Ray Emission from the Galactic Star Cluster Westerlund 1
    Astrophysical Journal 650, 203 (2006)
  • F. Yusef-Zadeh, H. Bushouse, C. D. Dowell, et al.
    A Multiwavelength Study of SGR A*: The role of Near-IR Flares in Production of X-Ray, Soft Gamma-Ray, And Submillimeter Emission
    Astrophysical Journal 644, 198 (2006)
  • A. Eckart, F. K. Baganoff, R. Schodel, et al.
    The Flare Activity of Sagittarius A - New Coordinated mm to X-Ray Observations
    Astronomy & Astrophysics 450, 535 (2006)
  • S. Boldyrev and F. Yusef-Zadeh
    Turbulent Origin Of The Galactic Center Magnetic Field: Nonthermal Radio Filaments
    Astrophysical Journal 637, L101 (2006)
  • G. Belanger, A. Goldwurm, M. Renaud, et al.
    A Persistent High-Energy Flux From The Heart Of The Milky Way: Integral'S View Of The Galactic Center
    Astrophysical Journal 636, 275 (2006)
  • F. Yusef-Zadeh, J. Biretta, and M. Wardle
    Proper Motion of the Irradiated Jet HH 399 in the Trifid Nebula
    Astrophysical Journal 624, 246 (2005)
  • S. D. Hyman, J. W. Lazio, N. E. Kassim, et al.
    A Powerful Bursting Radio Source towards the Galactic Centre
    Nature 434, 50 (2005)