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of the IGM high enough to cause the suppression of emission observed. Despite the fact that the ratio of neutral hydrogen to ionized hydrogen may not have been particularly high, the low flux observed past the Lyman-alpha limit indicates that the universe was in the final stages of reionization.
150:≈ 6 appeared to conflict with estimates made from the WMAP measurement of the electron column density. However, the WMAP III data released in 2006 now seems to be in much better agreement with the limits on reionization placed by observation of the Gunn–Peterson trough.
133:
the surrounding IGM. However, as the scattering cross section of photons with energies near that of the Lyman-alpha limit with neutral hydrogen is very high, even a small fraction of neutral hydrogen will make the
79:
For over three decades after the prediction, no objects had been found distant enough to show the Gunn–Peterson trough. It was not until 2001, with the discovery of a quasar with a redshift
95:= 5.99, and, while each of these exhibited absorption at wavelengths on the blue side of the Lyman-alpha transition, there were numerous spikes in flux as well. The flux of the quasar at
99:= 6.28, however, was effectively zero beyond the Lyman-alpha limit, meaning that the neutral hydrogen fraction in the IGM must have been larger than ~10.
296:
Kogut, A.; et al. (2003). "First-Year
Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Temperature-Polarization Correlation".
129:, the universe was expected to be neutral, until the first objects in the universe started emitting light and energy which would
408:
349:
Page, L.; et al. (2007). "Three-Year
Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Polarization Analysis".
121:= 6 presented strong evidence for the hydrogen in the universe having undergone a transition from neutral to ionized around
413:
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84:
28:
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Zero flux troughs by different Lyman absorbers in the spectrum of first confirmed observation of the effect.
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87:, that a Gunn–Peterson trough was finally observed. The article also included quasars at redshifts of
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spacecraft in 2003, the determination by Becker that the end of reionization occurred at
117:= 6.28 quasar, and the absence of the trough in quasars detected at redshifts just below
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of the emitted light. This effect was originally predicted in 1965 by
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243:~ 6: Detection of a Gunn–Peterson Trough in a z = 6.28 Quasar".
143:
197:"On the Density of Neutral Hydrogen in Intergalactic Space"
83:= 6.28 by Robert Becker and others using data from the
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from the quasar at wavelengths less than that of the
43:. The trough is characterized by suppression of
142:Following the first release of data from the
8:
362:
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351:Astrophysical Journal Supplement Series
298:Astrophysical Journal Supplement Series
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195:Gunn, J. E.; Peterson, B. A. (1965).
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113:The discovery of the trough in a
16:Feature of the spectra of quasars
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35:due to the presence of neutral
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41:Intergalactic medium (IGM)
103:Evidence for reionization
21:astronomical spectroscopy
85:Sloan Digital Sky Survey
45:electromagnetic emission
76:
409:Astrophysics concepts
201:Astrophysical Journal
74:
245:Astronomical Journal
27:is a feature of the
25:Gunn–Peterson trough
373:2007ApJS..170..335P
320:2003ApJS..148..161K
267:2001AJ....122.2850B
213:1965ApJ...142.1633G
414:Physical cosmology
176:Lyman-alpha forest
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364:astro-ph/0603450
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311:astro-ph/0302213
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258:astro-ph/0108097
251:(6): 2850–2857.
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168:Astronomy portal
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109:Reionization
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51:line at the
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125:= 6. After
91:= 5.82 and
49:Lyman-alpha
403:Categories
182:References
107:See also:
389:12113374
336:15253442
283:14117521
154:See also
131:reionize
53:redshift
37:hydrogen
369:Bibcode
316:Bibcode
263:Bibcode
209:Bibcode
39:in the
33:quasars
29:spectra
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23:, the
385:S2CID
359:arXiv
332:S2CID
306:arXiv
279:S2CID
253:arXiv
144:WMAP
59:and
377:doi
355:170
324:doi
302:148
271:doi
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217:doi
205:142
31:of
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