University of Portsmouth | 2017 May 19
[img3="A slice through largest-ever three-dimensional map of the Universe. Earth is at the left, and distances to galaxies and quasars are labelled by the lookback time to the objects (lookback time means how long the light from an object has been traveling to reach us here on Earth). The locations of quasars (galaxies with supermassive black holes) are shown by the red dots, and nearer galaxies mapped by SDSS are also shown (yellow).Astronomers have constructed the first map of the universe based on the positions of supermassive black holes, which reveals the large-scale structure of the universe.
The right-hand edge of the map is the limit of the observable Universe, from which we see the Cosmic Microwave Background (CMB) – the light “left over” from the Big Bang. The bulk of the empty space in between the quasars and the edge of the observable universe are from the “dark ages”, prior to the formation of most stars, galaxies, or quasars.
Image Credit: Anand Raichoor (École polytechnique fédérale de Lausanne, Switzerland) and the SDSS collaboration"]http://www.sdss.org/press-releases/wp-c ... _small.png[/img3][hr][/hr]
The map precisely measures the expansion history of the universe back to when the universe was less than three billion years old. It will help improve our understanding of ‘dark energy,’ the unknown process that is causing the universe’s expansion to speed up.
The map was created by scientists from the Sloan Digital Sky Survey (SDSS), an international collaboration including astronomers from the University of Portsmouth.
As part of the SDSS Extended Baryon Oscillation Spectroscopic Survey (eBOSS), scientists measured the positions of quasars -- extremely bright discs of matter swirling around supermassive black holes at the centres of distant galaxies. The light reaching us from these objects left at a time when the universe was between three and seven billion years old, long before the Earth even existed.
The map findings confirm the standard model of cosmology that researchers have built over the last 20 years. In this model, the universe follows the predictions of Einstein’s general theory of relativity but includes components that, while we can measure their effects, we do not understand what is causing them. ...
To make the map, scientists used the Sloan telescope to observe more than 147,000 quasars. These observations gave the team the quasars’ distances, which they used to create a three-dimensional map of where the quasars are. ...
Astronomers Make the Largest Map of the Universe Yet
Sloan Digital Sky Survey | 2017 May 19
The Clustering of the SDSS-IV Extended Baryon Oscillation Spectroscopic Survey DR14 Quasar Sample:
First Measurement of Baryon Acoustic Oscillations between Redshift 0.8 and 2.2 - Metin Ata et al
- arXiv.org > astro-ph > arXiv:1705.06373 > 17 May 2017