ESA | Science & Technology | Planck | 2016 Aug 31
[img3="Cosmic reionisation. Credit: ESA – C. Carreau"]http://sci.esa.int/science-e-media/img/ ... ted_2k.jpg[/img3]ESA's Planck satellite has revealed that the first stars in the Universe started forming later than previous observations of the Cosmic Microwave Background indicated. This new analysis also shows that these stars were the only sources needed to account for reionising atoms in the cosmos, having completed half of this process when the Universe had reached an age of 700 million years. ...
[img3="History of the Universe. Credit: ESA"]http://sci.esa.int/science-e-media/img/ ... c_1280.jpg[/img3][hr][/hr]
Observations of very distant galaxies hosting supermassive black holes indicate that the Universe had been completely reionised by the time it was about 900 million years old. The starting point of this process, however, is much harder to determine and has been a hotly debated topic in recent years. ...
In 2015, the Planck Collaboration provided new data to tackle the problem, moving the reionisation epoch even later in cosmic history and revealing that this process was about half-way through when the Universe was around 550 million years old. The result was based on Planck's first all-sky maps of the CMB polarisation, obtained with its Low-Frequency Instrument (LFI).
Now, a new analysis of data from Planck's other detector, the High-Frequency Instrument (HFI), which is more sensitive to this phenomenon than any other so far, shows that reionisation started even later – much later than any previous data have suggested. ...
The new study locates the formation of the first stars much later than previously thought on the cosmic timeline, suggesting that the first generation of galaxies are well within the observational reach of future astronomical facilities, and possibly even some current ones.
In fact, it is likely that some of the very first galaxies have already been detected with long exposures, such as the Hubble Ultra Deep Field observed with the NASA/ESA Hubble Space Telescope, and it will be easier than expected to catch many more with future observatories such as the NASA/ESA/CSA James Webb Space Telescope.
Planck Intermediate Results. XLVI. Reduction of Large-scale Systematic Effects
in HFI Polarization Maps and Estimation of the Reionization Optical Depth - Planck Collaboration: N. Aghanim et al
- Astronomy & Astrophysics (Accepted: 14 July 2016) DOI: 10.1051/0004-6361/201628890
arXiv.org > astro-ph > arXiv:1605.02985 > 10 May 2016 (v1), 26 May 2016 (v2)
- Astronomy & Astrophysics (Accepted: 23 July 2016) DOI: 10.1051/0004-6361/201628897
arXiv.org > astro-ph > arXiv:1605.03507 > 11 May 2016 (v1), 23 May 2016 (v2)
http://asterisk.apod.com/viewtopic.php?t=34424