11th CMB-S4 Workshop: Cosmology and Astrophysics in the Next Decade
Picture: 11th CMB-S4 Workshop: Cosmology and Astrophysics in the Next Decade
Owing to the ongoing COVID-19 pandemic the CMB-S4 workshop will be held entirely remotely, August 10 - 14, 2020. The meeting is open to everyone interested in the broad range of cosmology and astrophysics that CMB-S4 will impact. Registration is free.

This, the 11th workshop in the series of twice yearly CMB-S4 workshops, will focus on the CMB-S4 science case in conjunction with other experiments and probes. A key goal of the workshop is to engage with the broad community that is addressing science topics similar to those being pursued with CMB-S4, but using different techniques. We will discuss how CMB-S4 measurements can be used to advance these science topics in unique and complementary ways, and work on exploring powerful joint analysis of CMB and other probes.

Science topics
The workshop has dedicated sessions on the following science topics:
Synergies of Large Scale Structure Surveys with CMB-S4
We will focus on the synergies of combining tracers of large scale structure as measured at radio through X-ray wavelengths with the wide-field CMB-S4 survey, which will cover ~70% of the sky. We are particularly interested in exploring cosmological analyses that can only be done via the combination of multi-wavelength probes or that are significantly improved through the use of multiple probes (e.g., Nx2 pt, kSZ cosmology, CMB lensing tomography, cosmic shear/WL calibration, cluster cosmology, etc).

Exploiting the mm-wave window on the Transient Universe
CMB-S4 will open a new window onto the mm-wave transient sky, enabling new synergies with multimessenger astrophysics and time-domain astronomy in the coming decade. This session will be devoted to exploring those synergies and the survey landscape in the coming decade.

Complementarity of Cosmological and Beamline Neutrino Experiments
Over the next decade, a number of cosmological and terrestrial experiments will measure key properties of neutrinos including the neutrino mass scale and ordering, search for the existence of sterile neutrinos, and probe the generation mechanism of neutrino masses. This session will explore how these measurements can complement each other to fill out our picture of neutrino physics over the next decade, focusing on how CMB-S4 measurements of neutrino number and mass relate to, and can inform, other cosmological and laboratory probes.

Shedding Light on the Dark Sector
CMB-S4 will provide characteristically new insights into the physics of the dark sector across a wide range of mass, length, and coupling scales. We will discuss how CMB observations will complement and enhance other searches for dark sector physics. Topics will include means by which the CMB may provide insights for WIMPs and their interactions, light dark matter candidates such as axion-like particles, and light relics including dark radiation and relativistic species.

Dust and Magnetic fields in the Galaxy
CMB-S4 will make sensitive, high-resolution measurements of the Galactic polarized dust and synchrotron emission. We will discuss opportunities to determine the composition of interstellar dust, understand the role of magnetic fields in molecular cloud and star formation, and characterize turbulence in the ISM.

Illuminating the Circumgalactic Medium (CGM)
The next decade of mm-wave observations will transform our understanding of galaxy formation, driven by precisely measuring the thermodynamic properties of ionized gas, using the cosmic microwave background as a "backlight". In this session we will discuss how these observations will probe the CGM gas well into the outskirts of hitherto-unexplored high-redshift, low-mass systems and the synergies with other observables.

Astrophysics with High-Redshift Galaxies and Clusters
CMB-S4 will detect high redshift dusty galaxies out to z~9; protoclusters out to z~5 ; and massive galaxy clusters out to z~2. In this session we will discuss how CMB-S4 can shed light on the evolution from high-redshift dusty galaxies to protoclusters to galaxy clusters and highlight the insights and advances that studies of these discrete objects will bring to the field of astrophysics.

Observing Cosmic Dawn
Little is still known about the epoch of reionization as it continues to remain hidden from our view. In this session we will discuss what potential discoveries CMB observations will make about reionization and how it will approve our understanding of how stars, black holes, and galaxies first emerged. We will also discuss synergies with 21cm and intensity mapping observations.

Millimeter Survey of the Outer Solar System
With its millimeter-wave survey of roughly 70% of the sky approximately every two days, CMB-S4 will discover moving objects, such as asteroids, dwarf planets, or as yet undiscovered bodies such as Planet Nine, in difference images using their long-wavelength thermal emission. While an instrument such as ALMA would be far more sensitive for measuring the mm-wave imaging of a particular object, the unique and synergistic benefit of CMB-S4 will its nearly daily measurements of large numbers of bright objects over several years, along with wide sky coverage for discovery of new or unexpected objects.

Organizing Committee
Zeeshan Ahmed
KIPAC, SLAC National Accelerator Laboratory
Lindsey Bleem
Argonne National Laboratory
Julian Borrill
Berkeley Lab & UC Berkeley
John Carlstrom
University of Chicago, ANL
Simone Ferraro
Lawrence Berkeley National Laboratory
Lloyd Knox
University of California, Davis
Eric Linder
Lawrence Berkeley National Laboratory
Joel Meyers
Southern Methodist University
Anze Slosar
Brookhaven National Laboratory
Joaquin Vieira
University of Illinois Urbana-Champaign
Abigail Vieregg
University of Chicago / KICP
Nathan Whitehorn
University of California

The meeting is hosted by the University of Chicago and is held remotely on August 10 - 14, 2020.