MPA: Planck Reveals First Stars Were Born Late
Posted: Thu Feb 05, 2015 11:01 pm
Planck Reveals First Stars Were Born Late
Max Planck Institute for Astrophysics | 2015 Feb 05
Planck Reveals First Stars Were Born Late
ESA Space Science | Planck | 2015 Feb 05
Planck corrects WMAP: “Reionization” is more recent than predicted
International School for Advanced Studies (SISSA) | 2015 Feb 05
Planck Mission Explores the History of Our Universe
NASA | JPL-Caltech | 2015 Feb 05
Max Planck Institute for Astrophysics | 2015 Feb 05
New maps from ESA's Planck satellite uncover the "polarised" light from the early Universe across the entire sky, revealing that the first stars formed much later than previously thought. They also include information about our own Milky Way, showing that the contribution from dust in our galaxy is much more widespread than previously thought and revealing complex structures in the Galactic magnetic field. Researchers at the Max Planck Institute for Astrophysics developed important software components for Planck and take part in the scientific interpretation of the mission data; in particular, they contributed to the analysis of the signals from galaxy clusters, from gravitational lensing of the CMB, from Galactic dust and magnetic fields, as well as from primordial magnetic fields. ...
Light is polarised when it vibrates in a preferred direction, something that may arise as a result of photons - the particles of light - bouncing off other particles, such as electrons. This is exactly what happened when the CMB originated in the early Universe. Planck's polarisation data provide an independent way to measure cosmological parameters and thus confirm the details of the standard cosmological picture determined from CMB temperature fluctuations.
However, as the CMB light travelled through space and time it was also influenced by the first stars and the polarisation data now indicates that these started to shine about 550 million years after the Big Bang, ending the "Dark Ages". This is more than 100 million years later than previously thought but actually helps to resolve a problem: Previous studies of the CMB polarisation seemed to point towards an earlier dawn of the first stars, while very deep images of the sky indicated that the earliest known galaxies in the Universe (forming perhaps 300-400 million years after the Big Bang) would not have been powerful enough to succeed at ending the Dark Ages within 450 million years. The new evidence from Planck significantly reduces the problem, indicating that the earliest stars and galaxies alone might have been enough.
But the first stars are definitely not the whole story. With the new Planck data released today, scientists are also studying the polarisation of foreground emission from gas and dust in the Milky Way to analyse the structure of the Galactic magnetic field. ...
A series of scientific papers describing the new results was published on 5 February. They can be downloaded here.
Planck Reveals First Stars Were Born Late
ESA Space Science | Planck | 2015 Feb 05
Planck corrects WMAP: “Reionization” is more recent than predicted
International School for Advanced Studies (SISSA) | 2015 Feb 05
Planck Mission Explores the History of Our Universe
NASA | JPL-Caltech | 2015 Feb 05