Plan for the Exploitation and Dissemination of Results for BeyondPlanck

What kind of needs does the project respond to?

The aim of this project is to provide to the cosmological community state-of-the-art measurements and models of the microwave sky between 30 and 70 GHz. These types of measurements form a cornerstone in modern cosmology, and have during the last decades allowed us to probe the origin and evolution of the universe to unprecedented accuracy, from a fraction of a second after the Big Bang until today.

The next frontier in observational cosmology is the search for inflationary gravitational waves. According to current theories, these may be found in the large angular scale perturbations of the CMB polarization field. However, the amplitude of the signal is minute, possibly several orders of magnitude smaller than obscuring radiation from synchrotron and thermal dust radiation in the Milky Way, and interactions between this radiation and the instrumental characterization renders the overall analysis problem non-linear and highly convolved.

What kind of problem the proposed solution will solve and why this solution will be better than existing ones?

The single most important outstanding challenge regarding the existing data products are instrumental systematics induced by the presence of astrophysical foregrounds. Such systematics can only be mitigated by considering the entire analysis problem globally, fitting both astrophysical and instrumental parameters jointly. This has never been attempted to this date, due to lack of expertise, funding and time.

What new knowledge and results the project will generate?

The project will generate new knowledge on many fronts:

• In terms of hard data products, we will produce new state-of-the-art maps and models of the microwave sky between 30 and 70 GHz, a critical frequency range for modern cosmology, including both cosmological and astrophysical components.
• From these, we will derive new constraints on cosmological parameters and characteristics from large-scale polarization measurements that are robust with respect to instrumental and astrophysical systematics, including new measurements of the optical depth of reionization as well as limits on statistical anisotropy on large angular scales.
• The novel end-to-end methods we develop will be essential for next-generation CMB B- mode experiments searching for inflationary gravitational waves. Our analysis will serve as a real-world test-bed for experiments such as CORE, LiteBIRD, S4 and many others

Who will use these results?

The primary users of these results are cosmologists and astrophysicists at the highest international level. These products will serve as standard references for the entire microwave astronomy community until the next CMB satellite mission flies, which may be a decade or longer.

These products will also be used in public outreach and science communication to the public. Maps of the cosmic microwave background and the Milky Way appear everywhere from high-school physics textbooks via popular science, all the way to popular culture; for instance, the CMB temperature field appears regularly in the”Big Bang Theory” sitcom in the form of a beach ball.

What benefits will be delivered and how much benefit?

Because of the minute amplitude of the signals in question here, the main concern of most CMB cosmologists before Planck revolved around random instrumental noise. The emphasis was constantly on producing more and more sensitive maps. However, after the last generation of ultra- sensitive experiments such as Planck and BICEP2, the field has undergone a critical transition: the main challenge is now longer raw sensitivity, but rather astrophysical contamination and instrumental systematics. What we offer in this project is a viable algorithmic path through this problem, and as such open up the road to continued cosmological progress for the coming decade. Ultimately, this may lead to one of the biggest discoveries in modern cosmology, namely the detection of gravitational waves created during the Big Bang.

How will end users be informed about the generated results?

End-users will be informed through a six-level dissemination structure:

1. All main results will be published in international journals with a “Gold Open Access”policy, ensuring free access to everybody.
2. All data products will be published through open long-term data repositories, most notably the Planck Legacy Archive (PLA), funded and maintained by ESA.
3. All software products will be accessible through an open GitHub repository, allowing everybody to download, reuse and extend our work.
4. We will create a dedicated web page for the project as a whole, describing its background, purpose and status, including all necessary references to results, products and software.
5. Near the end of the project period, we will host an international conference dedicated to the discussion and dissemination of these results.
6. Throughout the project period, we will be pro-active in terms of seeking exposure in general media, both in terms of popular science and radio/TV shows.

All results and products will be available indefinitely through their respective dissemination channel. Once published, none of the adopted channels require continued funding from the current project. Furthermore, all data products will be released using industry-standard formats. For instance, all sky maps will be provided in HEALPix FITS format; all time-ordered data products will be released in HDF format; and all tabulated data will be provided in standard ASCII formats. No internal or proprietary formats will be employed, ensuring easy use for external users.

Communication activities

As described in the PEDR, the main dissemination strategy will build on six pillars:

1. Peer-reviewed publications in international journals As is customary in astrophysics, all main results will be published in international journals. The preferred journal for our purposes is Astronomy and Astrophysics (A&A), a peer-reviewed top-tier journal adminstrated by the European Southern Observatory (ESO). All publications from the Planck Collaboration have been published in A&A, and we will continue this tradition in the current project, maintaining the same rigorous quality levels and style guidelines as for the official Planck publications. Likewise, all Planck publications were published under a “Gold Access” license, ensuring open access to all external readers, and we will maintain the same policy in the current project.

   In addition to A&A, all publications will be posted on the arXiv preprint server, allowing early access to results and ensuring maximal exposure throughout the community. This is where most cosmologists read new results, and we will take advantage of this well-established structure.

2. Data deliveries through the Planck Legacy Archive The Planck Legacy Archive ( PLA; https://pla.esac.esa.int/pla ) was created as part of the first Planck data release, providing direct access to all main data products. It is funded by ESA, and will serve the cosmological community into the foreseeable future. We will take advantage of this existing infrastructure, and feed our final results back into the PLA near the end of the project period. Two of our project partners, Planetek and XAL, have been working on the PLA for the last two years, and are intimately familiar with its organization and structure.

3. Direct software access through open GitHub accounts By now, GitHub has become an effective industry standard in terms of software version control for large-scale projects, combining development and distribution into one convenient infrastructure. We will adopt this approach in our project, maintaining a semi-open software repository for all codes used. Specifically, all internal users will have full push and pull (write and read) rights, whereas external users will only have pull (read) rights. In addition to the continuously accessible software repository, we will provide a self-contained software package with necessary scripts (Makefiles, autoconf files etc.) to allow for easy compilation on most systems.

4. Dedicated project web page We will create a dedicated web page for the project (hosted by the University of Oslo to ensure long-term support), providing easy access and overview of the project to external users. This web page will include both a general introduction to cosmology for the general public, as well as detailed information regarding data and software access required for scientific purposes. It will also provide direct links to all associated repositories.

5. International conference hosted at the end of the project To ensure effective distribution of our results, we will host a major international conference dedicated to the dissemination and use of the derived results. This will follow in the footsteps of previous Planck release conferences, and the invited speakers will comprise a mix of internal researchers and external experts in the field. The exact time, location and duration will be decided ata later time, but one possible scenario is a one-week conference in Norway in late 2019 or early 2020.

6. Public outreach through general media.Cosmology and astrophysics are generally very popular topics in the general media, and we will exploit this interest to present our results to the public. As a simple example of such efforts, HKE has during the last year acted as an effective “house astronomer” for one of the biggest radio shows in Norway (“Norgesglasset”, P1, NRK), appearing often several times a month to discuss recent astronomical developments. The current project will be of great interest to such audiences. Other examples of such activities include popular science articles, general news articles and giving high- school lectures.