Archive for cosmological distance ladder

Early Dark Energy and Cosmic Tension

Posted in The Universe and Stuff with tags , , , , , on March 19, 2020 by telescoper

To avoid talking any more about you-know-what I thought I would continue the ongoing Hubble constant theme. Rhere is an interesting new paper on the arXiv (by Hill et al.) about the extent to which a modified form of dark energy might relieve the current apparent tension.

The abstract is:

 

You can click on this to make it bigger; you can also download the PDF here.

I think the conclusion is clear and it may or may not be related to a previous post of mine here about the implications of Etherington’s theorem.

Here’s my ongoing poll on the Hubble constant poll. Feel free to while away a few seconds of your time working from home casting a vote!

 

 

Gravitational Lensing, Cosmological Distances and the Hubble Constant

Posted in The Universe and Stuff with tags , , , on October 17, 2019 by telescoper

To continue the ongoing Hubble constant theme, there is an interesting paper on the arXiv by Shajib et al. about determining a distance to a gravitational lens system; I grabbed the above pretty picture from the paper.

The abstract is:

 

You can click on this to make it bigger. You will see that this approach gives a `high’ value of H0 ≈ 74.2, consistent with local stellar distances measures, rather than with the `cosmological’ value which comes in around H0 ≈ 67 or so. It’s also consistent with the value derived from other gravitational lens studies discussed here.

Here’s my ongoing poll on the Hubble constant, with