Archive for Simons Observatory

R.I.P. Jim Simons (1938-2024)

Posted in R.I.P., The Universe and Stuff with tags , , , , , on May 13, 2024 by telescoper

I heard yesterday of the death, at the age of 86, of Jim Simons. Jim Simons started out as an academic in the fields of mathematics and mathematical physics. Together with Shiing-Shen Chern he developed the Chern–Simons form, which has been of interest recently in the context of cosmology because of the potential for parity violation, and also contributed to the development of a theoretical framework to combine geometry and topology with quantum field theory. He then moved to into the world of hedge funds, and became a highly successful investor on Wall Street, amassing a huge personal fortune. In later life he turned back to his first loves, however, and set up the Simons Foundation which supports, among many other things, the Simons Observatory and the Flatiron Institute both of which have had, and will no doubt continue to have, an enormous impact in the fields of cosmology and astrophysics. The Simons Foundation has also made large donations to the arXiv.

R.I.P. Jim Simons (1938-2024)

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Simons Observatory News

Posted in Cardiff, Science Politics, The Universe and Stuff with tags , , , on October 18, 2022 by telescoper

It seems a lot longer than four years ago that I drew the attention of readers of this blog to the science case for the Simons Observatory, the next big thing in ground-based studies of the cosmic microwave background.

The Simons Observatory Site in Chile, as it appeared four years ago

Obviously a couple of years of pandemic have intervened, amongst other things, but I was delighted to read yesterday that the UK has invested £18M in the Simons Observatory, which will enable further development of the facility at Cerro Toco, high above the Atacama Desert in Chile.

Simons Observatory in May 2022

The project was already a large international collaboration led from the USA, but the new funds from UKRI mean that six UK institutions will now join. These are (in alphabetical order): Cambridge; Cardiff; Imperial College London; Manchester; Oxford; and Sussex. Although I’m not involved in this project myself I know many people at these institutions (two of which I have worked at) and elsewhere who will be absolutely thrilled to be able to participate in this exciting project. Congratulations to them!

It would have been great if Ireland had been able to get involved in the Simons Observatory, but sadly fundamental science of this type is not a priority for the powers that be in Irish science funding. This is unfortunate because I think membership of international consortia like this would enable a small country to punch above its weight in science. Still, at least the UK PI, Prof. Michael Brown (Manchester), is an Irishman…

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The Simons Observatory: Science Goals and Forecasts

Posted in The Universe and Stuff with tags , , on August 27, 2018 by telescoper

I haven’t been involved in this project, but several of my former colleagues at Cardiff have beenm and still are, so I know how much work has gone into this (especially by the amazing Erminia Calabrese), so I am happy to share this impressive work here. This long (54 pages) paper, which appeared on the arXiv last week, describes the latest step forward in ground-based cosmology using the cosmic microwave background. It shows just how rapid the onward march of instrumental technology continues to be.

The Simons Observatory Site, in Chile

It is likely that the Simons Observatory (based on a single 6m dish) will form part of the next generation CMB experiment known currently as CMB-S4.

You can download the paper in full from the arXiv here.

The Simons Observatory (SO) is a new cosmic microwave background experiment being built on Cerro Toco in Chile, due to begin observations in the early 2020s. We describe the scientific goals of the experiment, motivate the design, and forecast its performance. SO will measure the temperature and polarization anisotropy of the cosmic microwave background in six frequency bands: 27, 39, 93, 145, 225 and 280 GHz. The initial configuration of SO will have three small-aperture 0.5-m telescopes (SATs) and one large-aperture 6-m telescope (LAT), with a total of 60,000 cryogenic bolometers. Our key science goals are to characterize the primordial perturbations, measure the number of relativistic species and the mass of neutrinos, test for deviations from a cosmological constant, improve our understanding of galaxy evolution, and constrain the duration of reionization. The SATs will target the largest angular scales observable from Chile, mapping ~10% of the sky to a white noise level of 2 μK-arcmin in combined 93 and 145 GHz bands, to measure the primordial tensor-to-scalar ratio, r, at a target level of σ(r)=0.003. The LAT will map ~40% of the sky at arcminute angular resolution to an expected white noise level of 6 μK-arcmin in combined 93 and 145 GHz bands, overlapping with the majority of the LSST sky region and partially with DESI. With up to an order of magnitude lower polarization noise than maps from the Planck satellite, the high-resolution sky maps will constrain cosmological parameters derived from the damping tail, gravitational lensing of the microwave background, the primordial bispectrum, and the thermal and kinematic Sunyaev-Zel’dovich effects, and will aid in delensing the large-angle polarization signal to measure the tensor-to-scalar ratio. The survey will also provide a legacy catalog of 16,000 galaxy clusters and more than 20,000 extragalactic sources.

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