Jeff Cooke

ARC Future Fellow - Centre for Astrophysics & Supercomputing
Swinburne University of Technology, PO Box 218, Mail number H29, Hawthorn, VIC 3122 Australia
office: +61 3 9214 5392 -- fax: +61 3 9214 8797 -- email:

AR 315

Extragalactic Observational Astronomer

Main areas of research:
High redshift supernovae
High redshift galaxy interactions and environment Interstellar and intergalactic gas

Press releases:
Extremely distant superluminous supernovae
The most distant supernovae
The massive merging galaxy LBG-2377

'The Conversation' on superluminous supernovae
'Nature' News & Views
'Nature SciLogs'

Below are some brief descriptions of a few of the projects that have been keeping me busy. The links are in various states of completion. Thank you for your patience as I (slowly) update each link.

  Detection of z > 2 supernovae
  Super-luminous and pair-instability supernovae
  Type Ia supernovae and cosmology
  "Orphan" supernovae and the first stars

  Lyman break galaxy interactions at z ~ 3
  Broadband selection of Lyman alpha emitters
  Spectral correlation functions and environment
  Bright galaxies at z ~ 4; the One-Degree Deep survey
  Identifying key contributors to cosmic reionization

  Mass of damped Lyman alpha systems (DLAs)
  Galaxies and MgII absorption-line systems
  Metal-rich gas near the epoch of reionization

About a billion years after the Big Bang, the hydrogen in the Universe was ionized (changed from neutral gas to a plasma). It is believed that galaxies (the stars and supernovae in them) were responsible for the bulk of this change. Yet the number of galaxies found in distant surveys using standard selection methods and their individual contributions seem to fall short of doing the job.

Our new paper describes a technique we developed to measure the amount of escaping ionizing light from galaxies using the standard selection methods (termed Lyman break galaxies) and we also find that there are a significant number of galaxies that appear to have been missed in existing distant galaxy surveys. The missed galaxies, termed Lyman continuum galaxies, appear to have high fractions of escaping ionizing light and may have made a large contribution to the ionization of the Universe.

We recently confirmed the identification and redshift of a sample of Lyman continuum galaxies using the DEIMOS and MOSFIRE instruments on the Keck telescopes. We hope to use the LRIS instrument on Keck to directly measure the fraction of ionizing photons reaching Earth from these galaxies, thereby providing "smoking gun" evidence and a direct test of our predictions. In addition, we aim to use the WFC3 camera on the Hubble Space Telescope to acquire deep, high resolution imaging of these galaxies to determined the full extent of the ionizing photons and where they originate. This work is motivating new distant galaxy searches and opening up a new area of distant galaxy study.

Click here to access the ADS link displaying a list of articles describing my work.



Welcome to my office

Simulation of a super-luminous supernova and its host galaxy in the chaotic formative environment at high redshift (credit: Marie Martig and Adrian Malec, Swinburne University).

The Hubble Space Telescope

The Milky Way, as well as two of our closest companion galaxies, the Large and Small Magellenic Clouds, can be seen in this long-exposure image of the 4 meter telescope at the CTIO located in the Southern Hemisphere.
  Astronomy 110
Physics 20A  
  Physics 7D
Curriculum Vitae
  Astro Grad Seminar
Centre for Astrophysics & Supercomputing
  Caltech Astronomy Department
Center for Cosmology
UC Irvine
  Center for Astrophysics and Space Sciences
UC San Diego
W. M. Keck Observatory  
  Palomar Observatory