"It seems like a viable hypothesis that these runaway stars can contribute significantly to the ionizing radiation," says Brian Siana of the University of California, Riverside. "But the question is: Are they the dominant factor?" Siana says supernova explosions may have punched holes in the gas of the first galaxies, producing a Swiss cheese–like structure that allowed extreme ultraviolet radiation from hot stars to seep out of the galaxies, obviating the need for runaways.

Conroy and Kratter suggest a way to test their idea. Astronomers can't see individual stars at the great distances corresponding to the epoch of re-ionization. But if hot stars escaped the first galaxies, the galaxies themselves should look larger at wavelengths where they emitted ultraviolet light than at longer wavelengths, because the hot, ultraviolet-bright runaway stars had fled their homes. Seeing such distant galaxies is too tough a task even for the Hubble Space Telescope, but Conroy and Kratter say that 30-meter ground-based telescopes planned for the future should find them, shedding new light on the universe's ancient metamorphosis.

5 Comments

1. 1. rloldershaw 10:54 AM 7/31/12

   
   Another excellent class of candidates for the reionizers is "primordial" stellar-mass black holes, which also fit the bill for the dark matter.
   
   Discrete Scale Relativity definitively predicts the exact mass spectrum for these fundamental black holes, which are every bit as fundamental as protons of electrons.
   
   In fact, according to Leonard Susskind the only difference between fundamental particles and fundamental black holes is their mass/space/time scale.
   
   Robert L. Oldershaw
   http://www3.amherst.edu/~rloldershaw
   Discrete Scale Relativity
   Fractal Cosmology

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2. 2. scientific earthling 08:31 PM 7/31/12

   Light as far as humans are concerned is photons in a very small bandwidth. When the big bang took place, if it ever was so, you got elementary particles and some of them quickly became protons & neutrons, but no atoms till much later. So light, as we see it, could not have existed. Photons are generated when electrons move between different energy levels in an atom.

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3. 3. kenkoskinen in reply to scientific earthling 12:33 PM 8/3/12

   scientific earthing, you have it wrong. It is the excess photons of the early universe that were firstly able to free flow. This is so as after atoms formed they were neutral and no longer interacted with free flowing photons. The neutral atoms create virtual photons during energy changes within levels. It is the same today, even within your body and mine. If this were not so we would not exist and further nor would any stable matter.

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4. 4. kenkoskinen 12:41 PM 8/3/12

   I have to further add that real photons do interact with matter and this is the reason, for example, why things heat up. However it takes a lot of energy to ionize molecules/atoms. It takes a lot of energy to do this but we now things melt and or become gases. The next step is to become plasma and this is ionized gas.
   
   However the in the early universe when there was sufficient space/time expansion real photons did free flow and many missed the atomic targets. It is then we can say there was "light."

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5. 5. vinodkumarsehgal 08:37 AM 8/4/12

   Could any reader or author of this article indicate if astronomers have observed thru empirical means any runway star leaving MW galaxy or any other galaxy. Can't the hot stars ionize the gases while staying within galaxy?
   
   When a runway star leaves a star cluster or a binary pair within a galaxy, as the author has indicated, can't it be trapped again by the gravitation force of a black hole or a star cluster?

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