DES Supernovae - Weak Lensing Magnification Detected at 6σ! (Paul Shah & Tamara Davis)

Cosmology from Home registration: cosmologyfromhome.com/registr...
Paul Shah and Tamara Davis tell us about how they have used this wonderful supernova catalogue from the Dark Energy Survey to detect the weak lensing magnification signal for the first time. There has been evidence of this signal in earlier catalogues, but at no bigger than 1.4σ. They've got it at 6σ!
They do this by correlating the scatter in the magnitude of the supernovae with the over-under density in galaxy catalogues along the same lines of sight of the supernovae. Where there is more matter, the light from the supernova should be magnified, and where there is less matter it should be de-maginified. And they do indeed see that along overdense lines of sight the supernovae are, on average, ever so slightly brighter, and on underdense lines of sight the are ever so slightly dimmer.
I can't wait to see how this observable is used in the future to constrain all sorts of bits of cosmology. Nice work everyone!
Paul: paulshah.github.io/
Tamara: people.smp.uq.edu.au/TamaraDa...
The paper: arxiv.org/abs/2406.05047

[@talks_curator728]

*Index to Key Parts of the Talk*
[00:00] Shaun's intro
[01:20] Searching for gravitational lensing of SNe
[04:24] Two takeaways to remember
[05:43] Motivation for this work and why it could be done now
[10:22] The Hubble diagram of SN Ia
[11:16] What does a clumpy universe do to SN Ia?
[13:37] But can we detect it?
[14:46] Our data
[16:37] Our lensing estimator
[20:52] Correlate lensing estimate with Hubble diagram residuals
[27:01] The shape of dark matter haloes
[27:43] 'Adaptive optics' for dark matter
[30:49] What's next?
[34:23] Key results from DES-SN5YR weak lensing
[45:05] Further work anticipated?

[@0Navin0]

Very intriguing. I also wonder if the use of photometric information of the foreground galaxies will impact the results in this study. The fun part is, my comment also goes down in the history of this talk. :)

[@CosmologyTalks]

Haha, yeah. Congrats on your piece of history! 😁