News Center

Dark Energy Spectroscopic Instrument (DESI) Wins $1.1M Award

DESIlensblanksmall

The Heising-Simons Foundation has awarded $1.1M to the DESI project with the goal of helping to fabricate the unique optics needed to capture spectra of the young expanding universe.

BOSS Quasars Track the Expanding Universe – the Most Precise Measurement Yet

The Baryon Oscillation Spectroscopic Survey (BOSS) pioneered the use of quasars to chart the universe’s expansion and investigate the properties of dark energy through studies of large-scale structure. New techniques of analysis led by Berkeley Lab scientists, combined with other new BOSS quasar measures of the young universe’s structure, have produced the most precise measurement of expansion since galaxies formed.

Standard-Candle Supernovae are Still Standard, but Why?

Until recently, scientists thought they knew why Type Ia supernovae – the best cosmological “standard candles” – are all so much alike. But their favorite scenario was wrong. White dwarfs don’t all reach the Chandrasekhar limit, 1.4 times the mass of our sun, before they detonate in a massive thermonuclear explosion. Most Type Ia progenitors are less massive, and a few are even more massive. New work by the Berkeley Lab-based Nearby Supernova Factory can identify which theories of the strange circumstances that lead to a Type Ia explosion actually work and which don’t.

BOSS Measures the Scale of the Universe to One-Percent Accuracy

BOSS-BAO

The Baryon Oscillation Spectroscopic Survey (BOSS), the largest component of the third Sloan Digital Sky Survey, has measured the clustering of nearly 1.3 million galaxies spectroscopically to determine the “standard ruler” of the universe’s large-scale structure to within one percent, the most precise such measurement ever made.

BOSS Measures the Universe to One-Percent Accuracy

The Baryon Oscillation Spectroscopic Survey (BOSS), the largest component of the third Sloan Digital Sky Survey, has measured the clustering of nearly 1.3 million galaxies spectroscopically to determine the “standard ruler” of the universe’s large-scale structure to within one percent. This is the most precise such measurement ever made and is likely to establish the standard for years to come.

First Hundred Thousand Years of Our Universe

Berkeley Lab researchers take the furthest look back through time yet – 100 years to 300,000 years after the Big Bang – and find tantalizing new hints of clues as to what might have happened.

Unusual Supernova is Doubly Unusual for Being Perfectly Normal

Type Ia supernovae are indispensable milestones for measuring the expansion of the universe. With definitive measures of Supernova 2011fe, the same “Backyard Supernova” that thrilled amateur and professional astronomers alike in the summer of 2011, the Nearby Supernova Factory led by Lawrence Berkeley National Laboratory demonstrates that this unusually close-by Type Ia is such a perfect example of its kind that future Type Ia’s – and models meant to explain their physics – must be measured against it.

The Farthest Supernova Yet for Measuring Cosmic History

Supernova SCP-0401, nicknamed “Mingus,” was collected by the Hubble Space Telescope in 2004 but could not be positively identified until after the installation of a new camera that serendipitously acquired more data. (Photo Space Telescope Science Institute)

In 2004 the Supernova Cosmology Project used the Hubble Space Telescope to find a tantalizing supernova that appeared to be almost 10 billion light-years distant. But Berkeley Lab scientists had to wait until a new camera was installed on the Hubble years later before they could confirm the candidate’s identity and redshift as a Type Ia “standard candle.” The spectrum and light curve of supernova SCP-0401 are now known with clarity; it is the supernova furthest back in time that can be used for precise measurements of the expansion history of the universe.

Gordon and Betty Moore Foundation Gives a Big Boost to BigBOSS

BigBOSS-icon

Through UC Berkeley and the Berkeley Center for Cosmological Physics, the Gordon and Betty Moore Foundation has made a $2.1 million grant to Berkeley Lab’s BigBOSS project. The grant funds the development of key technologies for modifying the 4-meter Mayall Telescope on Kitt Peak and constructing a precision instrument to study dark energy by mapping tens of millions of galaxies and quasars over the entire Northern Hemisphere sky.

BOSS Quasars Unveil a New Era in the Expansion History of the Universe

Light from distant quasars (dots at left) is partially absorbed as it passes through clouds of hydrogen gas. A “forest” of hydrogen absorption lines in an individual quasar’s spectrum (inset) pinpoints denser clumps of gas along the line of sight, and the spectra are collected by the telescope’s spectrograph (square at right). Before BOSS, the Sloan Digital Sky Survey had collected spectra from 10 times fewer quasars (yellow dots) per square degree of sky in the accessible redshift range, which corresponds to about 10 billion years ago. By measuring the spectra from many more quasars in this range (red dots), BOSS can reconstruct a three-dimensional map of the otherwise invisible gas, revealing the large-scale structure of the early universe. (Illustration by Zosia Rostomian, LBNL; Nic Ross, BOSS Lyman-alpha team, LBNL; and Springel et al, Virgo Consortium and Max Planck Institute for Astrophysics) (Click for best resolution)

By collecting tens of thousands of quasar spectra, the Baryon Oscillation Spectroscopic Survey (BOSS) has measured the large-scale structure of the early universe for the first time. Like backlights in the fog, the quasars illuminate clouds of hydrogen gas along the line of sight. No other technique can reach back over 10 billion years to probe structure at a time when the expansion of the universe was still decelerating and dark energy was yet to turn on.