The H0 game: E2E test

Licia Verde
ICREA & ICCUBIs there a problem?
First, be quanHtaHve
Cosmological-model
dependent

JL Bernal thesis defenseIs there a problem?
First, be quanHtaHve

Between 4 and 6 sigmas*

Summary of July 2019 KITP conference

courtesy of Vivien Bonvin
hQps://github.com/vbonvin/
Nature Astronomy 2019

Working hypothesis: early vs late
WHY?

rsH0
But there is not much wiggle room in the middle!

Bernal e tal 2016, Aylor et al 2017

Where is the problem?
Is it in any speciﬁc data set? (keeping the standard LCDM context)
Early. For a while some people put the blame on Planck….
BUT H0(Early) does not budge if
you take Planck (or CMB data) out
Completely (even for Neﬀ-extended models
Shonenberg et al 2019)

Before who dropped Planck used instead
WMAP+ACT/SPT.

R19

BAO+BBN+He abundance
Planck 18

NOT in CMB data

Aside: if not Lya BAO, use SNe

Shonenberg et al 2019

Neﬀ freeWHY?
Cooke et al.

Aver et al (Yp)

Deuterium

HeliumWhere is the problem?
Is it in any speciﬁc data set?

All low z determinaHons (except 1)
hoover above 70.

Let’s invoke BACCUS
Bernal & Peacock 2018

BACCUS allows an unknown shik (systemaHc error) in each measurement e.g.,:

Let’s invoke BACCUS
Bernal & Peacock 2018
BACCUS allows an unknown shik (systemaHc error) in each (low z)
measurement:
SH0ES+
H0LiCOW+
SBF+
Masers+TRGB/
ExHncHonI I

2.6(2.8) or 99.1%(99.5%) CL away from a H0 value of 68 (67.4) km/s/ Mpc

A word on the meaning of these percentages

Both 5 σ discovery level and BACCUS were moHvated byDoing both would be

Where is the problem?
If not in the data then in the model…?

Where is the problem?
If not in the data then in the model…?
Early-Hme measurements assume standard LCDM.
EﬀecHvely this yields rd (the length of the standard ruler)z ~0 measurements do not do assumpHons about cosmology

BAO+SNE
SH0ES

Shall we look
pre or aker recombinaHon?

Fig.J.L. Bernal

See L. Knox talk andKnox Millea 2019

Post recombinaHon?
I leave to ADAM to discuss what can be changed in SN, Cepheids, etc.
Including screening and MG (creaHve aQempt in H. Desmond talk) etc.
My take: it’s complicated as it would have to aﬀect several diﬀerent things at once,including Hme-delay distances
Increase the freedom of H(z); Bernal, Raveri, Joudaki, Keeley…
The price is high: many extra degrees of freedom (epicycles?)
It is also very hard to change rs by 7% one has to Hnker with wb (hard) , wm (by ~20%)
Without changing maQer radiaHon equality scale in the CMB…
It is also hard to just mess around with the standard ruler as seen in BAO

My slides from 2017

The anchoring is uncomfortable

But not quite at this stage yet…

Up up…
no down a liQle…

Maybe now we are at this stage…

Some soluHons avoid
Shonenberg et al 2019
constraint
Change sound speed
Change the iniHal condiHons
Extra components
Extra interacHons among (early) components
Change H(z)pre-recombinaHon soluHons
Modify the model right where we most like it
Decrease the sound horizon, by 7%
without wreaking havoc on damping tail… and everything else

Reminds me ofﬁne tuning

Knox & Millea 2019pre-recombinaHon soluHons
Modify the model right where we most like it
Decrease the sound horizon, by 7%
without wreaking havoc on damping tail… and everything else

Early dark energy… aﬀects the damplig tail (can look for signatures)
Change iniHal condiHons
Extra components/ Extra interacHons/Energy injecHon (localized!)High T recombinaHon
Change H(z) à change of inferred wm with scale
Cyr-Racine, Knox talks

These are not all equivalent!

Beyond H0
This is not just a H0 problem.
It is a Ωm problem tooBernal et al in prep.

And.. What’s the age of the Universe anyway?

How old is the Universe?

Jimenez et al 2019very-low-metallicity stars
HD140283 (Bond et a l2013)
J18082002-5104378 A (Schlaufman et al 2018)

O’Malley et al ‘18 22 GC

How old is the Universe anyway?
PlanckSH0ES

BAO+SNe

Early : high t0
Late: low t0?
D. Valcin

TheoreHcal soluHons
Should improve (or not worsen) other tensions
We should quanHfy improvement vs predictability (degrees of freedom)
Parallelism with Λ…..
Model-dependent vs model independent approaches
At what point are we adding epicycles?

Cassini