Live from the Euclid Meeting!

In this post we have a live report from Sami Niemi, Euclid Visible Imager Instrument Scientist, from the Euclid Consortium Annual Meeting

This blog post discusses briefly the Euclid Mission and Euclid Consortium Meeting held in Leiden on May 13 – 16, 2013.


Our very best knowledge, based on many astronomical observables, implies that the Universe we live in is made mostly out of two entities we currently know rather little about. Because we know so little about them we have decided to call them simply dark energy and dark matter. Together these two dark components constitute about 95 per cent of the energy density of the Universe. We do know that these two entities interact with light and with more common material called baryons, we are made out of, via gravity. However, because we have not managed to detect any light from either dark energy or matter (hence the name “dark”), the little knowledge we have managed to gather thusfar is based on indirect probes. It is clearly unsatisfactory to not know about 95 per cent of everything that surrounds us, but how can we make progress on something we cannot directly see?

A part of the astronomical community had acknowledged the lack of knowledge in dark matter and energy already some time ago and hence decided to propose a space mission to the European Space Agency (ESA) to study the dark Universe. After competitive process two proposals were joined to form a single space mission to help solve the mysteries of dark energy and dark matter. The Euclid mission was born.

The Euclid mission will use two complementary probes, namely weak gravitational lensing and galaxy clustering, to study the dark Universe. The launch date for the Euclid mission is 2020. But before we can unravel the mysteries of the Universe, a lot of work is required to make the mission reality.


To help make the Euclid mission reality a Euclid Consortium (EC) was founded. The Euclid Consortium consists of scientists, engineers, project managers, and technical staff and it is the largest astronomical community in Europe with about 1150 members. In the current Euclid organisation, the EC is responsible for the definitions of the scientific goals, the science requirements and the Euclid survey. It is also in charge of the design, construction, tests, integration and delivery to ESA of the imaging and spectroscopic instruments (VIS and NISP); the design, development tests, integration and operation of the data processing tools, pipelines and data centers; and the scientific analysis and interpretation of the Euclid data.

Members of the EC are working all the way from hardware to building of large cameras through development of shape and clustering measurement algorithms to finally the cosmological parameters describing the dark energy and dark matter. The Consortium therefore consists of experts from many disciplines. To fully exploit and share the expertise a Consortium level meeting is organised yearly. It is also the place to learn about Euclid and all the cool science it will enable.


I, Sami-Matias Niemi (VIS Instrument Scientist), am writing this blog post from the fourth Euclid Consortium Meeting held in Stadsgehoorzaal in a historic city of Leiden. In many ways the yearly EC meeting is not your typical astronomical science meeting. Firstly, about 400 people participate this years meeting, implying a large astronomical meeting. Secondly, the meeting is a mixture of technical and engineering talks and science presentations from theory to simulations and finally observations. Thus, the meeting is very multidisiplinary and provides enourmous amount of information regarding Euclid.

Now when the first meeting day is behind us, it is safe to say that this years meeting is the largest EC meeting ever. Up to six parallel splinter sessions are running simultaneously, so one must choose carefully to which ones to attend. For the morning part I had decided to catch up on the simulation activities and chose to join the Euclid Simulations splinter session.

Given that it will still be many years before Euclid will see its first light, we currently must rely on lab data and simulations. However, simulations are increasingly important in any astronomical exploitations, not only to predict the performance but also in achieving the scientific accuracy required. For example, to derive the cosmological parameters describing dark matter and energy a suite of simulations are required, so that we can be sure that we have probed the parameter space in an unbiased fashion. Without advancements, both technical and mathematical, the current brute force simulations would require billions of computer hours, so that even with the largest super computers (1 million CPUs) the simulations would still take a decade to run. Clearly advancements are needed to make the problem more manageable.

After the simulation session a few plenary talks were presented. The EC lead Yannick Mellier spoke briefly about the Euclid mission and the milestones since the last year’s meeting. Rene Laureijs (ESA) recapped the Euclid mission history since the selection six years ago, while Guiseppe Racca (ESA) enlightened us about the ESA Euclid management structure. The last plenary session, shared between Jerome Amiaux and Jose Lonrenzo Alvarez, discussed system engineering aspects of this 1 Billion Euro space mission.

In the afternoon more parallel splinter sessions discussing for example photometric redshifts, calibrations, supernova science, and science ready data and catalogues took place. I shall not go into details, but simply say that I was awed by the amount of work that has taken place since the previous meeting. I must however now stop my report, I do have a presentation to give…

Sami Niemi's Euclid VIS Presentation

Sami Niemi’s Euclid VIS Presentation


2 responses to “Live from the Euclid Meeting!

  1. Pingback: Weak Lensing in the Alps! | Late Universe@UCL·

  2. Pingback: 150 years of UK-Japan collaborations | mssl astro·

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