The Role of SN Ia in Current Cosmological Tensions

1 Oct 2024, 06:10 → 4 Oct 2024, 18:00 Europe/Madrid

Barcelona

The objective of the workshop is to test a new approach to cosmological tensions - and a new approach to workshops too. It will focus on the role of transients in cosmological tensions, especially the H₀ tension. This is particularly timely in light of the new DESI and DES SN Ia results, also in light of new JWST data and the start of Rubin-LSST time-domain observations. Particular focus will be put on the role of SN Ia (incl. lensed supernovae) in the apparent tensions and on how they can be combined with other probes to mitigate systematics inherent to any single method. 

The meeting is hybrid (in person + zoom). We envision that European participants will be in-person in Barcelona, and US participants will connect remotely. Morning presentations will be pre-recorded and watched a-synchronously on the European mornings. The afternoons in Europe (morning in USA) will be devoted to live discussions and structured collaboration. 

Two days will be devoted to supernovae, split between supernovae as cosmological probes per se and lensed supernovae to measure H₀. One day will be devoted to time delay lensing, and one day to the role of  peculiar velocity corrections both in the H₀ determination from distance ladder, masers or standard sirens.

The approach we would like to test is one of adversarial collaboration, a.k.a. Red Teaming.

For each topic we will set up  three teams. The blue team, which represents the teams responsible for a given measurement or result. The red team, made of experts who should challenge the blue team results in a constructive way with the goal of improving the robustness of the results. The white team: neutral coordinators who represent the view of the community  and who are in charge of building a consensus.

Confirmed participants, either remote or in-person, include: Dillon Brout, Tamara Davis, Isobel Hook, Suhail Dhawan, Mikael Rigault, Julien Lesgourgues, Lluís Galbany, Pat Kelly, Justin Pierel, Brenda Frye, Saurabh Jha, Anowar Shajib, Martin Millon, Claudio Grillo, Sherry Suyu, Dominique Sluse, Maria Vincenzi, Suvodip Mukherje, Richard Anderson, Guihelm Lavaux, Dillon Brout, Dan Scolnic, Ariel Goobar, Bruno Leibundgut, David Rubin, Dominique Pesce, Peter Schneider, George Efstathiou, Mark Reid, Hector Gil, Nils Schonberg, Eric Peteron, Khaled Said, Peter Garnavich, Mike Hudson, Licia Verde, Adam Riess, Frédéric Courbin.

Scientific Organizing Committee

• Frédéric Courbin
• Licia Verde
• Adam Riess

 

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Formulari d'inscripció. Informació detallada_en.pdf

Tuesday 1 October

10:00 Welcome coffee

1 Cosmological tensions - Pre-recorded

Pre-recorded: Overview of cosmology and tension on parameters, focusing on Ho

Speaker: George Efthathiou

2 Distances with type Ia Supernovae / Blue Team / Pre-recorded

State of the art of the field. What are the best data and methods ? How do the error bars are measured ? What are the measurements ? What are the claims ? What are the claimed limitations ?

Speaker: Isobel Hook

12:30 Coffee break & Discussions

3 Distances with type Ia Supernovae / Red Team forms and prepares constructive criticism

What the the limitations of the methods ? What could be hidden systematics ? Are there better methods to apply ? Is there any new astrophysical effect that may affect the measurement ?

Speaker: Bruno Leibundgut

4 Distances with type Ia Supernovae / Red Team presents

Take home message. What would it take to convince the red team that the blue team is doing the correct thing and that what it claims it does is actually done ?

Speaker: Dan Scolnic

14:30 Lunch break - Time for discussions

5 Distances with type Ia Supernovae - Blue team forms and prepares answers

Speaker: Saurabh Jah

6 Distances with type Ia Supernovae / Blue Team to answer

Speakers: Isobel Hook, Saurabh Jah

17:00 Coffee break & Discussions

7 Distances with type Ia Supernovae / White team to form and present consensus

Find consensus and propose concrete tests to improve measurements and address criticism by blue team. Design guardrails to avoid unconscious bias.

8 Establishing guardrails - ALL teams

Based on state-of-the-art (blue team) and criticisms be red team, find a protocole to follow to mitigate at least some of the main drawbacks of Supernova distances, if not all.