scholarly journals CORRECTING A STATISTICAL ARTIFACT IN THE ESTIMATION OF THE HUBBLE CONSTANT BASED ON TYPE IA SUPERNOVAE RESULTS IN A CHANGE IN ESTIMATE OF 1.2%

2010 ◽  
Vol 723 (1) ◽  
pp. 966-968 ◽  
Author(s):  
Jørgen H. Petersen ◽  
Klaus K. Holst ◽  
Esben Budtz-Jørgensen
2019 ◽  
Vol 486 (2) ◽  
pp. 2184-2196 ◽  
Author(s):  
E Macaulay ◽  
R C Nichol ◽  
D Bacon ◽  
D Brout ◽  
T M Davis ◽  
...  

ABSTRACT We present an improved measurement of the Hubble constant (H0) using the ‘inverse distance ladder’ method, which adds the information from 207 Type Ia supernovae (SNe Ia) from the Dark Energy Survey (DES) at redshift 0.018 < z < 0.85 to existing distance measurements of 122 low-redshift (z < 0.07) SNe Ia (Low-z) and measurements of Baryon Acoustic Oscillations (BAOs). Whereas traditional measurements of H0 with SNe Ia use a distance ladder of parallax and Cepheid variable stars, the inverse distance ladder relies on absolute distance measurements from the BAOs to calibrate the intrinsic magnitude of the SNe Ia. We find H0 = 67.8 ± 1.3 km s−1 Mpc−1 (statistical and systematic uncertainties, 68 per cent confidence). Our measurement makes minimal assumptions about the underlying cosmological model, and our analysis was blinded to reduce confirmation bias. We examine possible systematic uncertainties and all are below the statistical uncertainties. Our H0 value is consistent with estimates derived from the Cosmic Microwave Background assuming a ΛCDM universe.


1999 ◽  
Vol 183 ◽  
pp. 68-68
Author(s):  
Koichi Iwamoto ◽  
Ken'Ichi Nomoto

The large luminosity (MV ≈ −19 ∼ −20) and the homogeneity in light curves and spectra of Type Ia supernovae(SNe Ia) have led to their use as distance indicators ultimately to determine the Hubble constant (H0). However, an increasing number of the observed samples from intermediate- and high-z (z ∼ 0.1 − 1) SN Ia survey projects(Hamuy et al. 1996, Perlmutter et al. 1997) have shown that there is a significant dispersion in the maximum brightness (∼ 0.4 mag) and the brighter-slower correlation between the brightness and the postmaximum decline rate, which was first pointed out by Phillips(1993). By taking the correlation into account, Hamuy et al.(1996) gave an estimate of H0 within the error bars half as much as previous ones.


1995 ◽  
Vol 75 (3) ◽  
pp. 394-397 ◽  
Author(s):  
Peter Nugent ◽  
David Branch ◽  
E. Baron ◽  
Adam Fisher ◽  
Thomas Vaughan ◽  
...  

2019 ◽  
Vol 631 ◽  
pp. A165
Author(s):  
Richard I. Anderson

Assessing the significance and implications of the recently established Hubble tension requires the comprehensive identification, quantification, and mitigation of uncertainties and/or biases affecting H0 measurements. Here, we investigate the previously overlooked distance scale bias resulting from the interplay between redshift and Leavitt laws in an expanding Universe: Redshift-Leavitt bias (RLB). Redshift dilates oscillation periods of pulsating stars residing in supernova-host galaxies relative to periods of identical stars residing in nearby (anchor) galaxies. Multiplying dilated log P with Leavitt Law slopes leads to underestimated absolute magnitudes, overestimated distance moduli, and a systematic error on H0. Emulating the SH0ES distance ladder, we estimate an associated H0 bias of (0.27 ± 0.01)% and obtain a corrected H0 = 73.70 ± 1.40 km s−1 Mpc−1. RLB becomes increasingly relevant as distance ladder calibrations pursue greater numbers of ever more distant galaxies hosting both Cepheids (or Miras) and type-Ia supernovae. The measured periods of oscillating stars can readily be corrected for heliocentric redshift (e.g. of their host galaxies) in order to ensure H0 measurements free of RLB.


2019 ◽  
Vol 498 (1) ◽  
pp. 1420-1439 ◽  
Author(s):  
Kenneth C Wong ◽  
Sherry H Suyu ◽  
Geoff C-F Chen ◽  
Cristian E Rusu ◽  
Martin Millon ◽  
...  

ABSTRACT We present a measurement of the Hubble constant (H0) and other cosmological parameters from a joint analysis of six gravitationally lensed quasars with measured time delays. All lenses except the first are analysed blindly with respect to the cosmological parameters. In a flat Λ cold dark matter (ΛCDM) cosmology, we find $H_{0} = 73.3_{-1.8}^{+1.7}~\mathrm{km~s^{-1}~Mpc^{-1}}$, a $2.4{{\ \rm per\ cent}}$ precision measurement, in agreement with local measurements of H0 from type Ia supernovae calibrated by the distance ladder, but in 3.1σ tension with Planck observations of the cosmic microwave background (CMB). This method is completely independent of both the supernovae and CMB analyses. A combination of time-delay cosmography and the distance ladder results is in 5.3σ tension with Planck CMB determinations of H0 in flat ΛCDM. We compute Bayes factors to verify that all lenses give statistically consistent results, showing that we are not underestimating our uncertainties and are able to control our systematics. We explore extensions to flat ΛCDM using constraints from time-delay cosmography alone, as well as combinations with other cosmological probes, including CMB observations from Planck, baryon acoustic oscillations, and type Ia supernovae. Time-delay cosmography improves the precision of the other probes, demonstrating the strong complementarity. Allowing for spatial curvature does not resolve the tension with Planck. Using the distance constraints from time-delay cosmography to anchor the type Ia supernova distance scale, we reduce the sensitivity of our H0 inference to cosmological model assumptions. For six different cosmological models, our combined inference on H0 ranges from ∼73 to 78 km s−1 Mpc−1, which is consistent with the local distance ladder constraints.


1996 ◽  
Vol 470 (1) ◽  
pp. L7-L9 ◽  
Author(s):  
David Branch ◽  
Adam Fisher ◽  
E. Baron ◽  
Peter Nugent

2018 ◽  
Vol 609 ◽  
pp. A72 ◽  
Author(s):  
Suhail Dhawan ◽  
Saurabh W. Jha ◽  
Bruno Leibundgut

The most precise local measurements of H0 rely on observations of Type Ia supernovae (SNe Ia) coupled with Cepheid distances to SN Ia host galaxies. Recent results have shown tension comparing H0 to the value inferred from CMB observations assuming ΛCDM, making it important to check for potential systematic uncertainties in either approach. To date, precise local H0 measurements have used SN Ia distances based on optical photometry, with corrections for light curve shape and colour. Here, we analyse SNe Ia as standard candles in the near-infrared (NIR), where luminosity variations in the supernovae and extinction by dust are both reduced relative to the optical. From a combined fit to 9 nearby calibrator SNe with host Cepheid distances from Riess et al. (2016) and 27 SNe in the Hubble flow, we estimate the absolute peak J magnitude MJ = −18.524 ± 0.041 mag and H0 = 72.8 ± 1.6 (statistical) ±2.7 (systematic) km s-1 Mpc-1. The 2.2% statistical uncertainty demonstrates that the NIR provides a compelling avenue to measuring SN Ia distances, and for our sample the intrinsic (unmodeled) peak J magnitude scatter is just ~0.10 mag, even without light curve shape or colour corrections. Our results do not vary significantly with different sample selection criteria, though photometric calibration in the NIR may be a dominant systematic uncertainty. Our findings suggest that tension in the competing H0 distance ladders is likely not a result of supernova systematics that could be expected to vary between optical and NIR wavelengths, like dust extinction. We anticipate further improvements in H0 with a larger calibrator sample of SNe Ia with Cepheid distances, more Hubble flow SNe Ia with NIR light curves, and better use of the full NIR photometric data set beyond simply the peak J-band magnitude.


2020 ◽  
Vol 80 (9) ◽  
Author(s):  
Bing Xu ◽  
Kaituo Zhang ◽  
Qihong Huang

AbstractIn this paper, we probe the cosmic opacity with the newest Pantheon type Ia supernovae (SNIa) and the observational Hubble parameter $$\left( H(z)\right) $$ H ( z ) data based on the $$\Lambda $$ Λ CDM and wCDM models with or without spatial curvature. In the analysis, we marginalize the likelihood function of SNIa data over the pertinent nuisance parameter $${\mathcal {M}}$$ M , a combination of the absolute magnitude of SNIa $$M_{\mathrm{B}}$$ M B and the Hubble constant $$H_0$$ H 0 , with a flat prior. Two parameterizations of the optical depth $$\tau (z)$$ τ ( z ) associated to the cosmic absorption, namely $$\tau (z)=2\varepsilon z$$ τ ( z ) = 2 ε z and $$\tau (z)= (1+z)^{2\varepsilon }-1$$ τ ( z ) = ( 1 + z ) 2 ε - 1 , are adopted. We find that the results are not sensitive to the fiducial cosmological models, the spatial curvature and parameterizations of $$\tau (z)$$ τ ( z ) . Moreover, the results from the Pantheon data alone are consistent with a transparent universe ($$\varepsilon =0$$ ε = 0 ). And once the H(z) data is combined, $$\varepsilon =0$$ ε = 0 falls within the 68% confidence level (CL) of the best fit when a flat $$H_0$$ H 0 prior or the distance priors are used, while it falls within the 95% CL when a Gaussian distribution prior of $$H_0=74.03\pm 1.42$$ H 0 = 74.03 ± 1.42 km $$\mathrm {s}^{-1}\, \mathrm {Mpc}^{-1}$$ s - 1 Mpc - 1 is used.


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