We have created a map on the sky of something invisible — dark matter! Even though we can't see dark matter, its gravity bends light and makes galaxies appear to make a specific pattern across the sky. #DarkBitesIllustration: Chihway ChangText: Niall JeffreySee and read about our weak lensing "mass map", the largest of its kind, here: arxiv.org/pdf/2105.13539.pdf ... See MoreSee Less

View on Facebook

· Share

Share on Facebook Share on Twitter Share on Linked In Share by Email

The Dark Energy Survey

7 days ago

Every galaxy on the sky lives in a larger Dark Matter halo, like an invisible house -- galaxy-galaxy lensing reveals the shape of the house. #darkbitesIllustration/Text: Chihway ChangThe paper describing our galaxy-galaxy lensing results is here: arxiv.org/abs/2105.13541 ... See MoreSee Less

View on Facebook

· Share

Share on Facebook Share on Twitter Share on Linked In Share by Email

The Dark Energy Survey

1 week ago

The way galaxies cluster together tells us about how structures in the Universe form and evolve, but to see them we have to look through Earth’s atmosphere and the stars in our own galaxy. We have to correct for contaminations before we can learn about distant galaxies. #DarkBitesIllustration: Jessie MuirText: Martin Rodríguez-MonroyThe paper describing how we correct for these contaminations is here: arxiv.org/abs/2105.13540 ... See MoreSee Less

View on Facebook

· Share

Share on Facebook Share on Twitter Share on Linked In Share by Email

The Dark Energy Survey

2 weeks ago

#pride ... See MoreSee Less

View on Facebook

· Share

Share on Facebook Share on Twitter Share on Linked In Share by Email

The Dark Energy Survey

2 weeks ago

Airplane pilots use flight simulators to train because it lets them plan routes and test techniques without the risks of flying a real plane. Similarly, before using real measurements to infer the properties of the Universe, we analyze simulated DES data. These simulated analyses let us test-drive our calculations and code: we know what went into making the simulation, so we can check that we recover the right answer! #DarkBitesIllustration & Text: Jessie Muir This paper details how we use simulated analyses to define and validate our modeling pipeline: arxiv.org/abs/2105.13547 ... See MoreSee Less

View on Facebook

· Share

Share on Facebook Share on Twitter Share on Linked In Share by Email

News

Scientists Leverage HPC and AI to Wrangle the ‘Galaxy Zoo’

July 8, 2019 12:00 pm

The research team developed a new approach to classifying these hundreds of millions of galaxies. Instead of relying on crowdsourced classification, the researchers used knowledge from the state-of-the-art Xception neural network, combined with the datasets generated by the Galaxy Zoo project, to train its deep learning models. They then applied the trained model to galactic images from the Dark Energy Survey (DES) – where it achieved a 99.6% accuracy in identifying spiral and elliptical galaxies.

Three sky surveys completed in preparation for Dark Energy Spectroscopic Instrument

July 8, 2019 12:00 pm

It took three sky surveys — conducted at telescopes in two continents, covering one-third of the visible sky, and requiring almost 1,000 observing nights – to prepare for a new project that will create the largest 3-D map of the universe’s galaxies and glean new insights about the universe’s accelerating expansion. This Dark Energy Spectroscopic Instrument (DESI) project will explore this expansion, driven by a mysterious property known as dark energy, in great detail. It could also make unexpected discoveries during its five-year mission.

Multiple Measurements close in on Dark Energy

May 6, 2019 12:00 pm

An extensive analysis of four different phenomena within the universe points the way to understanding the nature of dark energy, a collaboration between more than 100 scientists reveals. Dark energy – the force that propels the acceleration of the expanding universe – is a mysterious thing. It’s nature, write telescope scientist Timothy Abbott from the Cerro Tololo Inter-American Observatory, in Chile, and colleagues, “is unknown, and understanding its properties and origin is one of the principal challenges in modern physics”. Indeed, there is a lot at stake. Current measurements indicate that dark energy can be smoothly incorporated into the theory of general relativity as a cosmological constant; but, the researchers note, those measurements are far from precise and incorporate a wide range of potential variations.

Viewpoint: Dark Energy Faces Multiple Probes

May 1, 2019 12:00 pm

One of the top goals in cosmology today is understanding the dark energy that is responsible for the accelerated expansion of the Universe. Is the dark energy consistent with the cosmological constant of general relativity—representing a constant energy density filling space homogenously? Or can we find deviations from general relativity on cosmological scales that suggest a more complex nature for gravity? Questions like these motivate the current and next generations of surveys that aim to map out ever larger volumes of the Universe, using a wide variety of probes to constrain the properties of dark energy. The Dark Energy Survey (DES) has now derived such constraints from the combined analysis of four canonical observables related to dark energy: supernovae, baryon acoustic oscillations, gravitational lensing, and galaxy clustering [1]. The resulting bounds confirm what we knew from previous studies, which focused on single probes. But the results indicate that this multiprobe approach could allow surveys in the 2020s to improve such constraints by orders of magnitude, possibly bringing us close to solving the dark energy puzzle.

Supernovae, Dark Energy, and the Fate of Our Universe

April 5, 2019 12:00 pm

What’s the eventual fate of our universe? Is spacetime destined to continue to expand forever? Will it fly apart, tearing even atoms into bits? Or will it crunch back in on itself? New results from Dark Energy Survey supernovae address these and other questions. At present, the fabric of our universe is expanding — and not only that, but the its expansion is accelerating. To explain this phenomenon, we invoke what’s known as dark energy — an unknown form of energy that exists everywhere and exerts a negative pressure, driving the expansion. Since this idea was first proposed, we’ve conducted decades of research to better understand what dark energy is, how much of it there is, and how it influences our universe.