Ryan Keeley
ryankeeley.bsky.social
Ryan Keeley
@ryankeeley.bsky.social
Astroparticle Physicist / Cosmologist
Lecturer at UC Irvine
Associate Member of the CGWU https://gwuniverse.snu.ac.kr/people/associate-members
https://rekeeley.github.io
Reposted by Ryan Keeley
Meh. As shown in arxiv.org/abs/2503.14743, you can use an even more general non-parametric Gaussian process regression, and if you think the result of that is consistent with w=-1 LCDM then we should have a discussion ...
April 2, 2025 at 9:12 AM
Big thanks to collaborators @abazajian.net , Manoj, and Arman
February 19, 2025 at 6:22 AM
So if the DESI preference for evolving DE is robust, further evidence for it could come in the form of a modified growth history, which would show up as a flattening of fsigma8(z)
February 19, 2025 at 6:22 AM
Another interesting part of the paper is that we calculated the growth functions that correspond to these DE models. Even within GR, changing the Universe’s expansion history will change the growth history.
February 19, 2025 at 6:22 AM
We don’t really need the contour as a function of parameters but only need the chi^2 value that corresponds to that contour. So that’s what we calculate here, the chi^2 value where 95% of the chi^2 values are better than it.
February 19, 2025 at 6:22 AM
One of the interesting things I did with this paper is a new way to calculate significance. Instead of claculating significance with corner plots, what one really wants instead is the contour that contains 95% of the volume of the posterior in the full N-D parameter space.
February 19, 2025 at 6:22 AM
Rather than plot the posterior in terms of parameters, I like plotting the posterior in terms of functions, to really see what the model is doing and what’s really going on with the data.
February 19, 2025 at 6:22 AM
The TDE parametrization of the DE EOS allows for a sharp transition compared to CPL where dw/da is constant. The DESI(+SN+CMB) dataset still prefers an evolving DE over LCDM.
February 19, 2025 at 6:22 AM
From this anomalous flux, we can characterize the population of low-mass dark matter halos which are determined by the microphysics of the dark matter particle and collect more clues to figure out what dark matter really is
May 6, 2024 at 1:39 AM
We measure the flux ratios of strongly lensed quasars and look for any anomalous flux, flux that would be caused by magnification from low-mass dark matter halos.
May 6, 2024 at 1:37 AM
This is also the most observational work I’ve done where I’m publishing data from the JWST, as well as constraints on DM physics from data; really doing that full-stack cosmology as I like to say
May 6, 2024 at 1:37 AM
Here, we calculate constraints on the free streaming length of dark matter (aka the mass of a thermally produced DM particle) and find dark matter must be heavier than 6.1 keV
May 6, 2024 at 1:37 AM