Welcome Letter

Dear friends, supporters, and visitors -

I am excited to be able to welcome you to Cosmology@Home. This participatory computing platform for cosmology enables participants to contribute actively to front-line research in cosmology by donating their CPU time. You might to like to find out about more about how C@H got started and share some news about major changes about to happen and where we are going.

When we first started Cosmology@Home in the Astronomy Department at the University of Illinois, I was joined in this effort by a talented budding computer scientist: Scott Kruger. After the explosive success, then physics PhD student Chad Fendt joined me in developing the machine learning tools and software stack that would allow us to harvest your computations to vastly accelerate high-precision computations of our Universe. The insight that allowed C@H to work was to use a combination of machine learning and participatory computing to accelerate the search through cosmological parameter space; the enabling technology there was PICO, one of the tools Chad built for his thesis. Through our involvement in Planck we received NASA funding to keep the lights on and later received significant further help through funding from the National Science Foundation for which we are very grateful.

We were quickly joined by graphics designers, amongst them Nikita Sorokin who is responsible for the current web page design. Then came volunteers amongst our first participants, who played a major role in animating and moderating the bulletin board on the C@H site. Most recently Marius Millea joined in with major revisions to the computational infrastructure on which C@H runs, preparing for an exciting future (more about that below).

The first goal of Cosmology@Home has been to farm out computations that help us understand the beginning, evolution and current state of the cosmos. As part of the Planck space mission C@H has helped find the models that best describe our Universe by enabling the rapid comparison of millions of models to the available astronomical and particle physics data. In order to achieve this goal, C@H participants have explored theoretical models with a larger number of different parameter combinations. As a result, C@H has played a major behind-the-scenes role in the analysis of Planck data - through allowing rapid parameter comparisons at various stages of the data analysis work. This role has been acknowledged in a recent publication that was entirely enabled by our work; but even the preparation of major Planck cosmological parameter and power spectrum papers was fueled by your computations under the hood. These papers are amongst the most frequently cited papers in all of astrophysics.

Planck is not over yet, and our computations are still contributing to Planck science. But we have lofty goals beyond Planck. When Marius revamped the software architecture of our work packages he did it with this future in mind. The most recent Planck challenge runs were both an exciting science application and a validation of this approach that vastly simplifies the process involved in launching new science to run on C@H.

In the meantime I moved to the Institute of Astrophysics in Paris (IAP), a unit of the Pierre and Marie Curie University (UPMC). Very soon afterwards I helped in the creation of the Lagrange Institute in Paris.

The IAP and the Lagrange Institute turn out to be the perfect places to host C@H. Members of these institutes are involved in several areas of theoretical and phenomenological cosmology, theoretical physics, and particle physics: the earliest instants of time, when the Universe formed, the cosmic microwave background, the cosmic dark ages, structure formation, the mysteries of dark matter and dark energy, as well as the development and adaptation of mathematics, statistics and computational methods to advance the state of cosmology. Cosmology@Home is now generating a great deal of interest amongst the leadership of Sorbonne University in Paris and we are now in the process of moving the operation of C@H to the IAP and the Lagrange Institute.

Most importantly, I would like to take this opportunity to thank you. My team and I have been overwhelmed by the level of community enthusiasm Cosmology@Home has generated right from the start. This made us realize the potential of Cosmology@Home as a way to connect our research with people all around the world who are excited (or at least curious!) about cosmology, astrophysics, particle physics and computing. Since its inception, tens of thousands of participants in hundreds of countries have contributed to front-line research in cosmology.

This success is humbling and motivates us to take this project to the next level. Now even more than before we understand C@H as an opportunity for a connection between cosmology enthusiasts worldwide and front-line research; and to provide the opportunity to help everyone to understand the exciting research they are contributing to. As part of the IAP and the Lagrange Institute it will be a part of a deeper involvement and communication with a broader audience for research in the physics of the Universe (astrophysics, cosmology, particle physics, theory, applied maths, computation, and statistics and data analysis).

As always, we are looking forward to your feedback on this and all other aspects of the project. Do not hesitate to contact us, either by e-mail or using the message boards related to Cosmology@Home.

All the best,

Ben Wandelt, for the Cosmology@Home team

Professor and International Chair
Institut d’Astrophysique de Paris
Director, Lagrange Institute
Universite Pierre et Marie Curie (UPMC)
Centre Nationale de Recherche Scientifique (CNRS)
Sorbonne University