Latest BICEP2/Keck Array/Planck results on primordial gravitational waves


30 January 2015 - A new joint analysis of BICEP2/Keck Array and Planck data fits the CMBR polarization measurements carried out by these experiments to an improved model of galactic dust and a possible contribution from primordial gravitational waves generated by inflation. This new analysis yields a new upper limit for the contribution from primordial gravitational waves but no longer disfavours a zero contribution at high statistical significance. The authors conclude that to better constrain, or to definitively detect, primordial inflationary gravitational waves will therefore require additional data. Hence for the moment the search for primordial gravitational waves continues, although the authors note that many other experiments to measure CMBR polarization are currently underway.

LSC Congratulates BICEP2 Colleagues

18 March 2014 - The BICEP2 Collaboration result, if confirmed, is a landmark discovery in cosmology, allowing us for the first time to peer back almost to the moment of the Big Bang through the observation of the imprint of primordial gravitational waves on the cosmic microwave background. The LIGO Scientific Collaboration congratulates our BICEP colleagues on their accomplishment and will further follow discoveries and implications of these observations with great interest.

This result highlights the unique role that gravitational wave observations will play in understanding the universe in the coming years, demonstrating the possibility to study the earliest time in the evolution of the Universe, and the physics of the correspondingly high energies, using gravitational waves. Direct measurements of the cosmological gravitational waves at a variety of frequencies will be necessary to fully understand the physics of inflation. Furthermore, when Advanced LIGO gravitational-wave detector comes online in the second half of this decade, we anticipate it will directly measure gravitational waves created by the most violent compact astrophysical sources in the universe -- colliding neutron stars and black holes as well as supernovae -- opening an entirely new window onto the universe through gravitational-wave astronomy.

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BICEP2 Results

An image from the Planck mission representing dust emission

The color scale in this image from the Planck mission represents the emission of dust. The highlighted region shows the position of the sky that was observed with BICEP2 and the Keck Array.
Image credit: ESA/Planck Collaboration