MPA: Planck Reveals First Stars Were Born Late

[bystander]

Planck Reveals First Stars Were Born Late
Max Planck Institute for Astrophysics | 2015 Feb 05

The interaction between interstellar dust in the Milky Way and the structure of our Galaxy's magnetic field, as detected by ESA's Planck satellite over the entire sky. (Credits: ESA and the Planck Collaboration)

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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

[MargaritaMc]

ESA: Planck Reveals First Stars Were Born Late

The History of the Universe

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Released 05/02/2015 3:00 pm
Copyright ESA
Description
A summary of the almost 14 billion year history of the Universe, showing in particular the events that contributed to the Cosmic Microwave Background, or CMB.

The timeline in the upper part of the illustration shows an artistic view of the evolution of the cosmos on large scales. The processes depicted range from inflation, the brief era of accelerated expansion that the Universe underwent when it was a tiny fraction of a second old, to the release of the CMB, the oldest light in our Universe, imprinted on the sky when the cosmos was just 380 000 years old; and from the ‘Dark Ages’ to the birth of the first stars and galaxies, which reionised the Universe when it was a few hundred million years old, all the way to the present time.

Tiny quantum fluctuations generated during the inflationary epoch are the seeds of future structure: the stars and galaxies of today. After the end of inflation, dark matter particles started to clump around these cosmic seeds, slowly building a cosmic web of structures. Later, after the release of the CMB, normal matter started to fall into these structures, eventually giving rise to stars and galaxies.

The inserts below show a zoomed-in view on some of the microscopic processes taking place during cosmic history: from the tiny fluctuations generated during inflation, to the dense soup of light and particles that filled the early Universe; from the last scattering of light off electrons, which gave rise to the CMB and its polarisation, to the reionisation of the Universe, caused by the first stars and galaxies, which induced additional polarisation on the CMB.

PLANCK 2015 RESULTS
The first release of the 2015 PLANCK results using the full mission data are presented here. These recent results are produced by the Planck Collaboration. The papers are available online, and links to each are provided below. If you use any of these results for presentations, please acknowledge the corresponding paper, ESA/Planck, and the Planck Collaboration. The Planck Legacy Archive (PLA) contains all public products originating from the Planck mission.

[Beyond]

I find it interesting that the 300-500 million year picture and the 13.8 billion year picture (the present) greatly resemble some neural net pictures of the human brain.