STScI: Cosmic Magnifying Glasses Measure Universe's Expansion
Posted: Fri Jan 10, 2020 7:27 pm
Cosmic Magnifying Glasses Yield Independent Measure of Universe's Expansion
NASA | GSFC | STScI | HubbleSite | 2020 Jan 08
H0LiCOW XIII. A 2.4% measurement of H0 from lensed quasars:
5.3σ tension between early and late-Universe probes ~ Kenneth C. Wong et al
NASA | GSFC | STScI | HubbleSite | 2020 Jan 08
New Hubble Measurement Strengthens Discrepancy in Universe's Expansion Rate
A team of astronomers using NASA's Hubble Space Telescope has measured the universe's expansion rate using a technique that is completely independent of any previous method.Each of these Hubble Space Telescope snapshots reveals four distorted images of a
background quasar surrounding the central core of a foreground massive galaxy. The
multiple quasar images were produced by the gravity of the foreground galaxy, which
is acting like a magnifying glass by warping the quasar’s light in an effect called
gravitational lensing. Quasars are extremely distant cosmic streetlights produced by
active black holes. The Hubble images were taken between 2003 and 2004 with the
Advanced Camera for Surveys. Credits: NASA, ESA, S.H. Suyu (MPA, Technical Univ
of Munich, and ASIAA) and K.C. Wong (Univ of Tokyo’s Kavli IPMU)
Knowing the precise value for how fast the universe expands is important for determining the age, size, and fate of the cosmos. Unraveling this mystery has been one of the greatest challenges in astrophysics in recent years. The new study adds evidence to the idea that new theories may be needed to explain what scientists are finding.
The researchers' result further strengthens a troubling discrepancy between the expansion rate, called the Hubble constant, calculated from measurements of the local universe and the rate as predicted from background radiation in the early universe, a time before galaxies and stars even existed.
This latest value represents the most precise measurement yet using the gravitational lensing method, where the gravity of a foreground galaxy acts like a giant magnifying lens, amplifying and distorting light from background objects. This latest study did not rely on the traditional "cosmic distance ladder" technique to measure accurate distances to galaxies by using various types of stars as "milepost markers." Instead, the researchers employed the exotic physics of gravitational lensing to calculate the universe's expansion rate. ...
The research team derived the H0LiCOW value for the Hubble constant through observing and analysis techniques that have been greatly refined over the past two decades.
H0LiCOW and other recent measurements suggest a faster expansion rate in the local universe than was expected based on observations by the European Space Agency's Planck satellite of how the cosmos behaved more than 13 billion years ago.
The gulf between the two values has important implications for understanding the universe's underlying physical parameters and may require new physics to account for the mismatch. ...
H0LiCOW XIII. A 2.4% measurement of H0 from lensed quasars:
5.3σ tension between early and late-Universe probes ~ Kenneth C. Wong et al
- arXiv.org > astro-ph > arXiv:1907.04869 > 10 Jul 2019 (v1), 06 Nov 2019 (v2)