Thursday, September 29, 2016

Record-Breaking 1.2 Million Galaxies in Hunt For Dark Energy

Record-Breaking 1.2 Million Galaxies in Hunt For Dark Energy



In the quest for measuring the dark energy that causes the universe to expand at a rapid rate, a team of physicists and astronomers created a record-breaking map of 1.2 million galaxies. This map is the biggest three-dimensional map of distant galaxies ever created.

“We have spent five years collecting measurements of 1.2 million galaxies over one quarter of the sky to map out the structure of the Universe over a volume of 650 cubic billion light years,” points out the research team’s co-leader Jeremy Tinker from the New York University. “This map has allowed us to make the best measurements yet of the effects of dark energy in the expansion of the universe. We are making our results and map available to the world.”

The measurements for the study, which will be published in the Monthly Notices of the Royal Astronomical Society, were made by the Baryon Oscillation Spectroscopic Survey (BOSS) program of the Sloan Digital Sky Survey-III.  This allows the scientists to quantify precisely the rate of the universe’s expansion and reveal how much dark energy and dark matter the universe currently has.

1.2 Million Galaxies
This is one slice through the map of the large-scale structure of the Universe from the Sloan Digital Sky Survey and its Baryon Oscillation Spectroscopic Survey. Each dot in this picture indicates the position of a galaxy six billion years into the past. Credit: Daniel Eisenstein and SDSS-III

BOSS shows the size of the baryonic acoustic oscillations (BAO) in the 3D distribution of galaxies. According to Ariel Sanchez of the Max-Planck Institute of Extraterrestrial Physics, BOSS helped them trace BAO’s imprint on the distribution of galaxies 2 to 7 billion years ago.

Moreover, the map shows the unique signature of the movement of galaxies toward areas of the Universe that have more matter as a result of the force of gravity attracting them. Natalie Roe, director of the physics division at Berkeley Lab, adds that the BAO measurements taken by BOSS will also lay the groundwork for future analysis using the Dark Energy Spectroscopic Instrument (DESI). DESI will provide a clearer 3D map to demonstrate how dark energy works.