Date

Published

H₀

km∙s⁻¹∙Mpc⁻¹

Observer

Remarks/Methodology

2021-12-08

73.3 ± 1.4

SH0ES

Cepheid-SN distance ladder (HST + Gaia EDR3 + Pantheon Plus SN Ia).

2021-09-17

69.8 ± 1.7

W. Freedman

Tip of the red-giant branch (TRGB) distance indicator (HST + Gaia EDR3).

2020-12-16

72.1 ± 2.0

Hubble Space Telescope and Gaia EDR3

Combining earlier work on red giant stars, using the tip of the red-giant branch (TRGB) distance indicator, with parallax measurements of Omega Centauri from Gaia EDR3.

2020-12-15

73.2 ± 1.3

Hubble Space Telescope and Gaia EDR3

Combination of HST photometry and Gaia EDR3 parallaxes for Milky Way Cepheids, reducing the uncertainty in calibration of Cepheid luminosities to 1.0%. Overall uncertainty in the value for H₀ is 1.8%, which is expected to be reduced to 1.3% with a larger sample of type Ia supernovae in galaxies that are known Cepheid hosts.

2020-12-04

73.5 ± 5.3

E. J. Baxter,

B. D. Sherwin

Gravitational lensing in the CMB is used to estimate H₀ without referring to the sound horizon scale, providing an alternative method to analyze the Planck data.

2020-11-25

${71.8}_{-3.3}^{+3.9}$

P. Denzel, et al.

Eight quadruply lensed galaxy systems are used to determine H₀ to a precision of 5%, in agreement with both “early” and “late” universe estimates. Independent of distance ladders and the cosmic microwave background.

2020-11-07

67.4 ± 1.0

T. Sedgwick,

et al.

Derived from 88 0.02 < z < 0.05 Type Ia supernovae used as standard candle distance indicators. The H₀ estimate is corrected for the effects of peculiar velocities in the supernova environments, as estimated from the galaxy density field. The result assumes Ωm = 0.3, ΩΛ = 0.7 and a sound horizon of 149.3 Mpc, a value taken from Anderson et al. (2014).

2020-09-29

${67.6}_{-4.2}^{+4.3}$

S. Mukherjee,

et al.

Gravitational waves, assuming that the transient ZTF19abanrh found by the Zwicky Transient Facility is the optical counterpart to GW190521. Independent of distance ladders and the cosmic microwave background.

2020-06-18

${75.8}_{-4.9}^{+5.2}$

T. de Jaeger, et al.

Use Type II supernovae as standardisable candles to obtain an independent measurement of H.

2020-02-26

${73.9}_{-3.0}^{+3.0}$

Megamaser Cosmology Project

Geometric distance measurements to Megamaser-hosting galaxies. Independent of distance ladders and the cosmic microwave background.

2019-10-14

${74.2}_{-3.0}^{+2.7}$

STRIDES

Modelling the mass distribution & time delay of the lensed quasar DES J0408-5354.

2019-09-12

${76.8}_{-2.6}^{+2.6}$

SHARP

H0LiCOW

Modelling three galactically lensed objects and their lenses using ground-based adaptive optics and the Hubble Space Telescope

2019-08-20

${70.3}_{-1.35}^{+1.36}$

K. Dutta, et al.

This is obtained analyzing low-redshift cosmological data within ΛCDM model. The datasets used are Type-Ia Supernova, Baryon Acoustic Oscillations, Time-Delay measurements using Strong-Lensing, measurements using Cosmic Chronometers and growth measurements from large scale structure observations.

2019-08-15

${73.5}_{-1.4}^{+1.4}$

M. J. Reid, D. W. Pesce, A. G. Riess

Measuring the distance to Messier 106 using its supermassive black hole, combined with measurements of eclipsing binaries in the Large Magellanic Cloud.

2019-07-16

${69.8}_{-1.9}^{+1.9}$

Hubble Space Telescope

Distances to red giant stars are calculated using the tip of the red-giant branch (TRGB) distance indicator.

2019-07-10

${73.3}_{-1.7}^{+1.7}$

H0LiCOW

collaboration

Updated observations of multiply imaged quasars, now using six quasars, independent of the cosmic distance ladder and independent of the cosmic microwave background measurements.

2019-07-08

${70.3}_{-5.0}^{+5.3}$

LIGO and Virgo

detectors

Uses radio counterpart of GW170817, combined with earlier gravitational wave and electromagnetic data.

2019-03-28

${68.0}_{-4.1}^{+4.2}$

Fermi-LAT

Gamma ray attenuation due to extragalactic light. Independent of the cosmic distance ladder and the cosmic microwave background.

2019-03-18

${74.03}_{-1.42}^{+1.42}$

Hubble Space Telescope

Precision HST photometry of Cepheids in the Large Magellanic Cloud (LMC) reduces the uncertainty in the distance to the LMC from 2.5% to 1.3%. The revision increases the tension with CMB measurements to the 4.4σ level (P = 99.999% for Gaussian errors), raising the discrepancy beyond a plausible level of chance. Continuation of a collaboration known as Supernovae, for the Equation of State of Dark Energy (SHoES).

2019-02-08

${67.78}_{-0.87}^{+0.91}$

Joseph Ryan,

et al.

Quasar angular size and baryon acoustic oscillations, assuming a flat LambdaCDM model. Alternative models result in different (generally lower) values for the Hubble constant.