The Hubble–Lemaître constant and sound horizon from low-redshift probes

Wojtak, Radosław; Agnello, Adriano

doi:10.1093/mnras/stz1163

Cited by 19 publications

(9 citation statements)

References 50 publications

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“…By anchoring the SN distance scale using distances measured from baryon acoustic oscillations (BAO), Macaulay et al (2019) measured an H 0 from the Dark Energy Survey consistent with that provided by the Planck Collaboration (2018) and that does not depend much on cosmological models, although the inference of H 0 is strongly affected by the assumptions of the size of the sound horizon (Aylor et al 2019). Recently, Jee et al (in press) and Wojtak & Agnello (2019) anchored the SN distance scale using D d measured from strongly lensed quasars, resulting in H 0 values with ∼10% uncertainty, limited by the precision of the D d measurements. With current data, lensed quasars yield tighter constraints on D ∆t than D d .…”

Section: Introductionmentioning

confidence: 91%

The Hubble constant determined through an inverse distance ladder including quasar time delays and Type Ia supernovae

Taubenberger

Suyu

Komatsu

et al. 2019

A&A

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Context. The precise determination of the present-day expansion rate of the Universe, expressed through the Hubble constant H 0 , is one of the most pressing challenges in modern cosmology. Assuming flat ΛCDM, H 0 inference at high redshift using cosmic microwave background data from Planck disagrees at the 4.4σ level with measurements based on the local distance ladder made up of parallaxes, Cepheids, and Type Ia supernovae (SNe Ia), often referred to as Hubble tension. Independent cosmological-modelinsensitive ways to infer H 0 are of critical importance. Aims. We apply an inverse distance ladder approach, combining strong-lensing time-delay distance measurements with SN Ia data. By themselves, SNe Ia are merely good indicators of relative distance, but by anchoring them to strong gravitational lenses we can obtain an H 0 measurement that is relatively insensitive to other cosmological parameters. Methods. A cosmological parameter estimate was performed for different cosmological background models, both for strong-lensing data alone and for the combined lensing + SNe Ia data sets. Results. The cosmological-model dependence of strong-lensing H 0 measurements is significantly mitigated through the inverse distance ladder. In combination with SN Ia data, the inferred H 0 consistently lies around 73-74 km s −1 Mpc −1 , regardless of the assumed cosmological background model. Our results agree closely with those from the local distance ladder, but there is a >2σ tension with Planck results, and a ∼1.5σ discrepancy with results from an inverse distance ladder including Planck, Baryon Acoustic Oscillations, and SNe Ia. Future strong-lensing distance measurements will reduce the uncertainties in H 0 from our inverse distance ladder.

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Section: Introductionmentioning

confidence: 91%

The Hubble constant determined through an inverse distance ladder including quasar time delays and Type Ia supernovae

Taubenberger

Suyu

Komatsu

et al. 2019

A&A

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“…Another option includes anchoring a distance ladder measurement to high-redshift calibrators, instead of lowredshift ones. For example, one can anchor the supernova Hubble diagram to high-redshift BAO distance measurements (Aubourg et al 2015;Macaulay et al 2019) or lensing time delay measurements (Wojtak & Agnello 2019), instead of local distance ladder measurements. This is known as the "inverse distance ladder" technique.…”

Section: Local Vs Globalmentioning

confidence: 99%

Can redshift errors bias measurements of the Hubble Constant?

Davis

Hinton

Howlett

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Redshifts have been so easy to measure for so long that we tend to neglect the fact that they too have uncertainties and are susceptible to systematic error. As we strive to measure cosmological parameters to better than 1% it is worth reviewing the accuracy of our redshift measurements. Surprisingly small systematic redshift errors, as low as 10 −4 , can have a significant impact on the cosmological parameters we infer, such as H 0 . Here we investigate an extensive (but not exhaustive) list of ways in which redshift estimation can go systematically astray. We review common theoretical errors, such as adding redshifts instead of multiplying by (1 + z); using v = cz; and using only cosmological redshift in the estimates of luminosity and angular-diameter distances. We consider potential observational errors, such as rest wavelength precision, air to vacuum conversion, and spectrograph wavelength calibration. Finally, we explore physical effects, such as peculiar velocity corrections, galaxy internal velocities, gravitational redshifts, and overcorrecting within a bulk flow. We conclude that it would be quite easy for small systematic redshift errors to have infiltrated our data and be impacting our cosmological results. While it is unlikely that these errors are large enough to resolve the current H 0 tension, it remains possible, and redshift accuracy may become a limiting factor in near future experiments. With the enormous efforts going into calibrating the vertical axis of our plots (standard candles, rulers, clocks, and sirens) we argue that it is now worth paying a little more attention to the horizontal axis (redshifts).

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“…Very recently, Pandey et al (2019) also carried out statistical tests independent of any underlying cosmology, showing that the distances measured with strong lensing time delays and with supernovae, i.e. both local but independent measurements, are fully compatible (see also Wojtak & Agnello 2019). Although they cannot exclude that supernovae and lenses share exactly the same systematics, these systematic biases would also have to be preserved across redshift, which seems unlikely.…”

Section: Introductionmentioning

confidence: 99%

TDCOSMO. I. An exploration of systematic uncertainties in the inference of $H_0$ from time-delay cosmography

Millon,

Galan,

Courbin

et al. 2019

Preprint

131

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Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement of the Hubble Constant, H 0 . As part of an ongoing effort to uncover and control systematic uncertainties, we investigate three potential sources: 1-stellar kinematics, 2-line-of-sight effects, 3deflector mass model. To meet this goal in a quantitative way, we mimic closely the H0LiCOW/SHARP/STRIDES procedures (i.e., TDCOSMO), and we find the following. First, stellar kinematics cannot be a dominant source of error or bias given current uncertainties. Second, we find no bias arising from incorrect estimation of the line-of-sight effects. Third, we show that elliptical composite (stars + dark matter halo), power-law, and cored power-law mass profiles have the flexibility to yield a broad range in H 0 values. However, the TDCOSMO procedures to model the data with both composite and power-law mass profiles are informative. If the models agree, as we observe in real systems owing to the "bulge-halo" conspiracy, H 0 is recovered precisely by both models. If the two models disagreed, as in the case of some pathological models illustrated here, the TDCOSMO procedure would either be able to discriminate between them through the goodness of fit, or account for the discrepancy in the final error bars provided by the analysis. This conclusion is consistent with a reanalysis of the TDCOSMO (real) lenses: the composite model yields H 0 =74.2 +1.6 −1.6 km s −1 Mpc −1 , while the power-law model yields 74.0 +1.7 −1.8 km s −1 Mpc −1 . In conclusion, we find no evidence of bias or errors larger than the current statistical uncertainties reported by TDCOSMO.

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The Hubble–Lemaître constant and sound horizon from low-redshift probes

Cited by 19 publications

References 50 publications

The Hubble constant determined through an inverse distance ladder including quasar time delays and Type Ia supernovae

The Hubble constant determined through an inverse distance ladder including quasar time delays and Type Ia supernovae

Can redshift errors bias measurements of the Hubble Constant?

TDCOSMO. I. An exploration of systematic uncertainties in the inference of $H_0$ from time-delay cosmography

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