... ionizing photons emitted in one recombination time equals the mean number of hydrogen ... a critical emission rate of hydrogen-ionizing photons per unit comoving volume, N ...
... The HIPASS H-alpha survey is a project to measure ionizedhydrogen in a sample of 500 galaxies selected via their 21-cm neutral hydrogen emission. ...
... With luminosities of 10 44 --10 45 erg s \Gamma1 the halos of ionizedhydrogen extend up to 100 kpc. ... is outside the cone of ionizing radiation from the obscured quasar, but in our line of sight in front of the ionizedhydrogen ...
... The Survey for Ionization in Neutral-Gas Galaxies (SINGG) is an NOAO survey program to measure the emission from ionizedhydrogen in a subset of the galaxies found by HIPASS. ...
... and is defined as U=ionizing photon flux per unit area/(hydrogen density * c ... parameter is defined as U=ionizing photon flux per unit area/(hydrogen density * c ... Fren . Required final fraction of ionizedhydrogen at model end (1%) . FQHeI . ...
... 1.5 Completed STIS/CCD 9066 (Closing in on the Hydrogen Re-ionization Edge of the Universe) The Space Telescope Imaging Spectrograph (CCD) was used in parallel constrain the Hydrogen re-ionization edge in emission that marks the transition from a neutral ...
... The neutral hydrogen and ionized helium absorption in the spectra of quasars probe ... ionizing radiation may actually have stimulated the dense, central regions of these ...
... The Epoch of Reionization (EoR) marks this second transition, during which time the 21-cm line excitation temperature should have risen, eventually exceeding the CMB temperature, until essentially all of the hydrogen was ionized. ...