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

By M. Millon, A. Galan, F. Courbin, T. Treu, Sherry H. Suyu, Xuheng Ding, Simon Birrer, G. Chen, Anowar J. Shajib, Dominique Sluse and 15 more. 2019

155 citations recorded by the source corpus.

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, 3- deflector 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 $H_0=74.2^{+1.6}_{-1.6}$ ${\, \mathrm{km}\, \mathrm{s}^{-1}\, \mathrm{Mpc}^{-1}}$, while the power-law model yields $74.0^{+1.7}_{-1.8}$ ${\, \mathrm{km}\, \mathrm{s}^{-1}\, \mathrm{Mpc}^{-1}}$. In conclusion, we find no evidence of bias or errors larger than the current statistical uncertainties reported by TDCOSMO.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/1a93b7e9b3776ff295742d29e6cc06d0ffd700de

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Nuclear and High Energy Physics

Citations in the corpus

Hubble Tension: The Evidence of New Physics (2023, methodology): “Since reanalyses of the Planck and local ladder measurements could not find a satisfactory answer to the H0 tension, hope was pinned on other observations, such as quasar lensing [37,143], Megamaser [144–148], gravitational waves (GW) [149–151], fast radio bursts (FRBs) [152–156], tip of the red gia”
TDCOSMO IV: Hierarchical time-delay cosmography -- joint inference of the Hubble constant and galaxy density profiles (2020, methodology): “Within the observables at disposal, one that A165, page 30 of 40 may be indicative of a different line of sight anisotropy is the higher ellipticity of the surface brightness and of the projected total mass distribution (Shajib et al. 2020b) of the TDCOSMO deflectors in comparison to the SLACS defle”