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The Megamaser Cosmology Project: IV. A Direct Measurement of the Hubble Constant from UGC 3789
Cosmology and Nongalactic Astrophysics · Submitted 31 Jul 2012
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim We find Ho = 68.9 +/- 7.1 km/s/Mpc; this estimate of Ho is independent of other methods and is accurate to +/-10%, including sources of systematic error.
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The abstract, sentence by sentence
In Papers I and II from the Megamaser Cosmology Project (MCP), we reported initial observations of water masers in an accretion disk of a supermassive black hole at the center of the galaxy UGC 3789, which gave an angular-diameter distance to the galaxy and an estimate of Ho with 16% uncertainty. We have since conducted more VLBI observations of the spatial-velocity structure of these water masers, as well as continued monitoring of its spectrum to better measure maser accelerations. These more extensive observations, combined with improved modeling of the masers in the accretion disk of the central supermassive black hole, confirm our previous results, but with signifcantly improved accuracy. We find Ho = 68.9 +/- 7.1 km/s/Mpc; this estimate of Ho is independent of other methods and is accurate to +/-10%, including sources of systematic error. This places UGC 3789 at a distance of 49.6 +/- 5.1 Mpc, with a central supermassive black hole of (1.16 +/- 0.12) x 10^7 Msun.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | In Papers I and II from the Megamaser Cosmology Project (MCP), we reported initial observations of water masers in an accretion disk of a supermassive black hole at the center of the galaxy UGC 3789, which gave an angular-diameter distance to the galaxy and an estimate of Ho with 16% uncertainty. | background 0.95 | 0.79 | 0.05 | asserted 1.00 |
| s1 | We have since conducted more VLBI observations of the spatial-velocity structure of these water masers, as well as continued monitoring of its spectrum to better measure maser accelerations. | method 0.80 | 0.95 | 0.02 | asserted 0.99 |
| s2 | These more extensive observations, combined with improved modeling of the masers in the accretion disk of the central supermassive black hole, confirm our previous results, but with signifcantly improved accuracy. | interpretation 0.41 | 0.74 | 0.13 | asserted 1.00 |
| s3 | We find Ho = 68.9 +/- 7.1 km/s/Mpc; this estimate of Ho is independent of other methods and is accurate to +/-10%, including sources of systematic error. | result 1.00 | 0.97 | 0.93 | asserted 1.00 |
| s4 | This places UGC 3789 at a distance of 49.6 +/- 5.1 Mpc, with a central supermassive black hole of (1.16 +/- 0.12) x 10^7 Msun. | result 1.00 | 0.94 | 0.12 | asserted 1.00 |
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The paper
Original abstract
In Papers I and II from the Megamaser Cosmology Project (MCP), we reported initial observations of water masers in an accretion disk of a supermassive black hole at the center of the galaxy UGC 3789, which gave an angular-diameter distance to the galaxy and an estimate of Ho with 16% uncertainty. We have since conducted more VLBI observations of the spatial-velocity structure of these water masers, as well as continued monitoring of its spectrum to better measure maser accelerations. These more extensive observations, combined with improved modeling of the masers in the accretion disk of the central supermassive black hole, confirm our previous results, but with signifcantly improved accuracy. We find Ho = 68.9 +/- 7.1 km/s/Mpc; this estimate of Ho is independent of other methods and is accurate to +/-10%, including sources of systematic error. This places UGC 3789 at a distance of 49.6 +/- 5.1 Mpc, with a central supermassive black hole of (1.16 +/- 0.12) x 10^7 Msun.
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References
How the literature uses it
10 arXiv papers cite this in 15 sentences
Papers citing it · 7 sentences without a confident label
Uses its data or values 7 papers
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These are: the three independent measurements used in Riess et al. 2016 (see table 6 in [ref] ), the relation between the integrated H$β$ line luminosity and the velocity dispersion of the ionized gas in HII galaxies and giant HII regions [ref] , megamasers [ref] and the $H_0$ value measured by the Cosmic Flows project [ref] .
Conservative cosmology: combining data with allowance for unknown systematics · Data and modelling · 1.00
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Planck CMB $67.27±0.60$ 2020 [ref] Planck CMB+lensing $67.36±0.54$ 2020 [ref] ACT CMB $67.9±1.5$ 2020 [ref] ACT+WMAP CMB $67.6±1.1$ 2020 [ref] BAO+RSD $69.13±2.34$ 2017 [ref] BAO+WMAP CMB $68.36_-0.52^+0.53$ 2019 [ref] BAO+BBN $66.98±1.18$ 2018 [ref] SnIa-Cepheid $73.20±1.30$ 2021 [ref] SnIa-Cepheid $74.03±1.42$ 2019 [ref] SnIa-Cepheid $73.48±1.66$ 2018 [ref] SnIa-Cepheid $72.80±2.70$ 2020 [ref] SnIa-Cepheid $73.00±2.70$ 2020 [ref] SnIa-TRGB $72.10±2.10$ 2020 [ref] SnIa-TRGB $69.60±1.90$ 2020 [ref] SnIa-TRGB $69.80±1.90$ 2019 [ref] SnIa-TRGB $72.40±2.00$ 2019 [ref] SnIa-Miras $73.30±4.00$ 2020 [ref] SnIa-SBF $73.30±2.50$ 2021 [ref] SnIa-SBF $70.50±4.10$ 2020 [ref] SnIa-SBF $71.90±7.10$ 2018 [ref] SneII $75.8_-4.9^+5.2$ 2020 [ref] Time-delay (TD) lensing $71.8_-3.3^+3.9$ 2021 [ref] TD lensing $73.3_-1.8^+1.7$ 2020 [ref] TD lensing $72.8_-1.7^+1.6$ 2020 [ref] TD lensing $74.2_-3.0^+2.7$ 20
Challenges for $\Lambda$CDM: An update · Baryon acoustic oscillations · 0.95
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To constrain the background cosmology, we use the following set of low-redshift observational data: * BAO measurements from different surveys including eBoss quasar clustering and Lyman-$α$ forest samples (see [ref] and references therein);2mm * latest Pantheon data for SNIa [ref] ;2mm * the OHD data for Hubble parameter at different redshifts [ref] ;2mm * strong lensing time-delay measurements by H0LiCOW experiment [ref] ;2mm * angular diameter distances measured using water megamasers under the Megamaser Cosmology Project [ref] ;2mm * finally the measurement of $H_0$ by [ref] [R16].
Beyond $\Lambda$CDM with Low and High Redshift Data: Implications for Dark Energy · Low redshift data only · 0.97
What it cites · 1 sentence without a confident label
Uses the method or tool of 1 paper
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The angular diameter distance is calculated rigorously from formulae of [ref] , assuming cosmological parameters for matter density $Ω_m=0.27$ and dark energy $Ω_Λ=0.73$.
Distance measures in cosmology · Modeling the Accretion Disk & Estimating · 1.00
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