Another successful collaboration meeting has come to a close. We had a great week in Philadelphia, PA. Be on the lookout for many new DES results later this year! #DESatPenn ... See MoreSee Less

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The Dark Energy Survey

6 days ago

For a couple hours each collaboration meeting, we put down the computers and put on the cleats for the collaboration football (soccer) match! We had at least 10^3 kicks of the ball, and given the systematics involved, we report no detections of non-GR gravitational effects on the ball. #DESatPenn ... See MoreSee Less

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The Dark Energy Survey

6 days ago

The work continues over coffee and snacks. #DESatPenn ... See MoreSee Less

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The Dark Energy Survey

1 week ago

We're into Day 3 of our biannual collaboration meeting. For much of the week, we split into our various science working groups (www.darkenergysurvey.org/collaboration-and-sponsors/) to discuss ongoing and future analyses. This picture comes from the Large-Scale Structure (LSS) session. #DESatPenn ... See MoreSee Less

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The Dark Energy Survey

1 week ago

Around 150 of our DES scientists from around the world have gathered in Philadelphia, PA, USA at the University of Pennsylvania for our biannual collaboration meeting! Lots of great talks and great science to be done this week! #DESatPenn ... See MoreSee Less

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News

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.

Measuring Distance In Space Using The Dark Energy Survey Portal

March 28, 2019 12:00 pm

Distance measurement is an important challenge in astronomy. Between the parallax of nearby stars and the redshift of the most distant galaxies, there are a lot of steps. With the Dark Energy rush, several large astronomical surveys are trying to understand the accelerated expansion of the universe. The Dark Energy Survey (DES) has just completed its observations last January, cataloging hundreds of millions of galaxies. Obtaining precise distance measurements of such a large number of galaxies is a hard task. To address this problem, photometric redshifts (photo-z’s) have been largely used by the astronomical community. Although less accurate than spectroscopic ones, they are cheaper and faster (regarding the number of galaxies measured per exposure time) and, hence, allow observations to go beyond signal-to-noise ratio limits of spectroscopic observations.

Cosmic fireworks in the clouds: Volunteer detectives sought for Magellanic Clouds Cluster Search

March 27, 2019 12:00 pm

Caught in a cosmic dance, our nearest neighbor galaxies, the Magellanic Clouds, are cartwheeling and circling each other as they fall toward our galaxy, the Milky Way. The gravitational interaction between the Clouds sparks cosmic fireworks—bursts of star formation as new clusters of stars flame on. How many and what kind of star clusters have been born this way over the history of the Clouds? A new project, the Local Group Cluster Search, invites citizen scientists to help find out! In contrast to the earliest studies of star clusters in the Magellanic Clouds, which used images captured on glass photographic plates, SMASH was carried out using the Dark Energy Camera (DECam), a 570-megapixel digital camera on the Blanco 4-m telescope at National Science Foundation's (NSF) Cerro Tololo Inter-American Observatory in Chile. Using DECam, astronomers obtained images that not only cover the full extent of the two galaxies but also are more sensitive to faint stars than any previous wide-field optical survey of the Clouds.