CosmoPhys

Two sets of White Paper submissions, Science and APC¹, are available in response to the Astro2020 Decadal Survey. CSV files of info on them are available at that site. I took those source files and created searchable HTML pages with links to the PDF files for each paper. What's searchable is the paper title, the principal author and their institution, a short description of the paper, and (for the Science White Papers) the NASA ADS Bibcode record. The ADS data was extracted from an AAS Bulletin.

Each of the two searchable webpages has a link to the other, as well as to the source data. The webpages are self-contained with all the data included in the html file, which contains the javascript code for the searches and the CSS for styling.

The original purpose in doing this was because many of the submissions were not on the arXiv, and I wanted to see what else was available and also so the PDF file link were all on one page. In addition, though, the search feature has been very useful.

This online-only conference featured 5 days of talks by cosmologists from 22-Jun-2020 to 26-Jun-2020. For anyone interested in the H0 tension problem, this is an excellent and highly recommended resource. Here are links to key resource information covering the conference.

A KITP-UCSB program running from Jan 6 to Mar 13, 2020 is an excellent resource for topics related to primordial universe cosmology (e.g., inflation, reheating (aka the Hot Big Bang), baryogenesis, non-gaussianity, dark sectors, cosmological sources of gravitational waves, Hubble tension, etc). The program agenda with links to videos and slides is here.

I'd like to point out an excellent overview talk from this program by Raphael Flauger on Feb. 28 that reviews Hubble measurement physics and results from each of the major determination methods and discusses current status on Hubble tension. The video for Flauger's talk is here. That page does not have the talk slides (at least not yet anyway) but the slides are available in PDF format here. Update: the slides are also now available on the KITP video page. Here is a PDF of the slides.

Link to paper: [2003.07355] Early Dark Energy Does Not Restore Cosmological Concordance, by J. Colin Hill, Evan McDonough, Michael W. Toomey, Stephon Alexander

Updates since this was originally posted:

• [2109.04451] The Atacama Cosmology Telescope: Constraints on Pre-Recombination Early Dark Energy , J. Colin Hill, et. al. Colin presents these results in a colloquium talk on 09-Sep-2021.
• In [2009.10740] Early dark energy is not excluded by current large-scale structure data a rebuttal is made and the authors “suggest that EDE still provides a potential resolution to the Hubble tension and that it is worthwhile to test the predictions of EDE with future data-sets and further study its theoretical possibilities.”
• Lead author Colin Hill was interviewed in a Cosmology Talk episode by Shaun Hotchkiss: Early dark energy doesn't make cosmology concordant again. Links to key parts of the video are available at the talk page.
• A detailed review of this paper was posted by cosmologist Sunny Vagnozzi on his blog here
• Follow-up paper: [2006.11235] Constraining Early Dark Energy with Large-Scale Structure, by Mikhail M. Ivanov, Evan McDonough, J. Colin Hill, Marko Simonović, Michael W. Toomey, Stephon Alexander, Matias Zaldarriaga. An astrobites article about it.

Background

Going back at least several years [1], but increasingly since late-2018 [2-7], there has been growing theoretical interest for the Hubble tension issue that suggests new physics models may be needed for the early universe prior to recombination that do not cause changes to late time cosmology, since that is tightly-constrained [4, 8].

For example, papers [2, 5] propose models for a new form of early dark energy (EDE) present at z ≳ 3000 that then dilutes away, resulting in a reduced sound horizon at decoupling. This results in a larger inferred $H_0$ value from CMB data versus Planck results, thus reducing the disparity between early and late time $H_0$ results.

These EDE proposals for resolving $H_0$ tension were characterized as being somewhere on the spectrum between “most plausible” [3] to “least unlikely” [4].

Colossus¹ is a recently available open-source, pure-python (nothing to compile) calculations toolkit developed by computational astrophysicist Benedikt Diemer during his PhD thesis work at University of Chicago.²

There are 3 separate python modules for cosmology, LSS, and DM Halos. You can choose to work with any of 20 built-in cosmology models based on results from Planck18 (with or w/o BAO), Planck15, Planck13, WMAP, etc. You can also create your own cosmology model by specifying values for a minimum of 6 parameters.

A paper on it is available at https://arxiv.org/abs/1712.04512. The code is available at this BitBucket repository. You can clone the repo, or download a zip file, or you can install it using pip. Documentation with many examples in html format is available here and the docs on the 3 modules are also available as interactive, live-code Jupyter notebooks here. The html tutorials doc files are just exports from the Jupyter notebooks.