iiinova — where your digital self keeps evolving

Tamara Davis @tamarastro.bsky.social · 08/09/2026

Unite allows us to put the tightest constraints yet on dynamic dark energy when combined with other probes, still finding a preference for time-variation. Congrats to Ryan Camilleri and Jason Lee who led this work! Here’s a Cosmology Talks video for those interested! www.youtube.com/watch?v=KT-j...

youtube.com

Cosmology from Combining Pantheon+ and DES-Dovekie (Camilleri, Davis and Lee)

YouTube video by Cosmology Talks

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Tamara Davis @tamarastro.bsky.social · 08/09/2026

Biggest updates in Unite were applying all the latest analysis updates to modernise the Pantheon+ data, applying weak-lensing corrections, and re-deriving all the host galaxy masses: Host galaxy mass paper led by Jason Lee: arxiv.org/abs/2609.05321

arxiv.org

Supernovae Unite: Host-Galaxy Mass Measurements of Type Ia Supernovae and Their Impact on Cosmology

Current consensus suggests that Type Ia supernova (SN Ia) brightnesses post light-curve standardization correlate with their host-galaxy stellar masses, which must be accounted for to obtain accurate ...

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Tamara Davis @tamarastro.bsky.social · 08/09/2026

Big news! Our new Unite supernova compilation is out! We’ve combined the Dark Energy Survey supernovae with all the previous supernovae compiled by Pantheon+, to make a compilation of 2884 homogeneously analysed type Ia supernovae. Cosmology results led by Ryan Camilleri: arxiv.org/abs/2609.05053

arxiv.org

Supernovae Unite: Combining Pantheon+ and DES-SN5YR

We present the Hubble diagram and cosmological constraints resulting from the combination of the Pantheon+ and DES-SN5YR supernova (SN) samples, which we refer to as Unite. Unite updates Pantheon+, in...

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Tamara Davis @tamarastro.bsky.social · 09/01/2024

All in all we've contributed ~80% of the high redshift supernovae (z>0.5) used for cosmology, which is a massive step up in our ability to determine the nature of dark energy. www.uq.edu.au/news/article...

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Tamara Davis @tamarastro.bsky.social · 09/01/2024

We found really conclusive evidence that the acceleration of the expansion of the Universe is real. And found tantalising hints that the dark energy (the name we give to whatever is causing the acceleration) might be changing with time (w>-1 for the experts).

Plot showing that the supernova data prefers an accelerating universe over the simplest non-accelerating one.

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Tamara Davis @tamarastro.bsky.social · 09/01/2024

Here's the light curves of 1635 supernovae measured in four colours. They brighten and fade in a couple of months, but their peak brightness is always about the same -- allowing us to use them as standard candles to measure the acceleration of the expansion of the Universe.

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Tamara Davis @tamarastro.bsky.social · 09/01/2024

Our DES supernova team discovered thousands of supernovae, and added 1635 of them to the "Hubble Diagram" to measure dark energy. About 1100 of them are so far away that they emitted the light we're seeing *before the Earth even formed*!!

Image of two light beams approaching Earth. The one emitted further away is redder on arrival than the one emitted closer.

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Tamara Davis @tamarastro.bsky.social · 09/01/2024

We did it! Today we released the Dark Energy Survey supernova cosmology results!!! A massive effort from many people. This has been the prime focus of my research for the last decade, and it was an honour to co-lead this working group. What did we find?....

Image of star field with a distant galaxy zoomed in showing a supernova exploding.

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