Department of Physics & Astronomy

George Becker

George Becker

George Becker

Assistant Professor

Pierce 2144B

Telephone: 951-827-5268
Email: george.becker@ucr.edu
Fax: 951-827-4529

Personal Home Page

Research Interests:

  • Extragalactic Astronomy, Intergalactic Medium, Cosmic Reionization, First Stars and Galaxies, Chemical Enrichment, Dark Matter, Optical and Infrared Spectroscopy


B.A., Astronomy-Physics, University of Virginia, 1999

Ph.D., Astrophysics, California Institute of Technology, 2006

Current Research:

My research focuses on using quasar absorption lines to study the intergalactic medium (IGM) when the Universe was less than a few billion years old. I am particularly interested in determining when and how the IGM became re-ionized by the first stars and active galactic nuclei.

The IGM contains most of the dark matter and baryons in the Universe, and provides the raw materials for galaxy formation. My group uses quasar absorption lines to measure the basic properties of the baryons, such as their temperature, chemical composition, and ionization state as a function of cosmic time.  These properties reflect the impact of galaxies and quasars on the IGM, and thus provide insight into the evolution of luminous objects from very early times up to the present day.  I am also interested in using the IGM to determine the nature of dark matter.

Recent Publications:

  1. "Reionization and high redshift galaxies: the view from quasar absorption lines," (Review Article) Becker, G. D., Bolton, J. S., & Lidz, A., 2015, PASA, in press (arXiv: 1510.03368)
  2. "Evidence of patchy hydrogen reionization from an extreme Lyα trough below redshift six," Becker G. D., Bolton J. S., Madau P., Pettini M., Ryan-Weber E. V., Venemans B. P., 2015, MNRAS, 447, 3402
  3. "Re-examining the case for neutral gas near the redshift 7 quasar ULAS J1120+0641," Bosman S. E. I., Becker G. D., 2015, MNRAS, 452, 1105
  4. "New Measurements of the Ionizing Ultraviolet Background over 2 < z < 5 and Implications for Hydrogen Reionization," Becker, G. D., & Bolton, J. S. 2013, MNRAS, 436, 1023
  5. "Warm Dark Matter as a solution to the small scale crisis: new constraints from high redshift Lyman-α forest data,” Viel, M., Becker, G. D., Bolton, J. S., & Haehnelt, M. G. 2013, PhRvD, 88, 043502
  6. "Iron and α-element Production in the First One Billion Years after the Big Bang Becker, G. D., Sargent, W. L. W., Rauch, M., & Carswell, R. F. 2012, ApJ, 744, 91”
  7. "High-Redshift Metals. II. Probing Reionization Galaxies with Low-Ionization Metal Lines at Redshift Six,” Becker, G. D., Sargent, W. L. W., Rauch, M., & Calverley, A. P. 2011, ApJ, 735, 93
  8. "Measurements of the UV background at 4.6 < z < 6.4 using the quasar proximity effect," Calverley, A. P., Becker, G. D., Haehnelt, M. G., & Bolton, J. S. 2011, MNRAS, 412, 2543
  9. "Detection of extended He II reionization in the temperature evolution of the intergalactic medium,” Becker, G. D., Bolton, J. S., Haehnelt, M. G., & Sargent, W. L. W. 2011, MNRAS, 410, 1096

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Maynard, Bonnie; Chair's Assistant, Academic Personnel
E-mail: bonnie.maynard@ucr.edu