TDCOSMO: I. An exploration of systematic uncertainties in the inference of H-0 from time-delay cosmography
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TDCOSMO : I. An exploration of systematic uncertainties in the inference of H-0 from time-delay cosmography. / Millon, M.; Galan, A.; Courbin, F.; Treu, T.; Suyu, S. H.; Ding, X.; Birrer, S.; Chen, G. C-F; Shajib, A. J.; Sluse, D.; Wong, K. C.; Agnello, A.; Auger, M. W.; Buckley-Geer, E. J.; Chan, J. H. H.; Collett, T.; Fassnacht, C. D.; Hilbert, S.; Koopmans, L. V. E.; Motta, Francis; Mukherjee, S.; Rusu, C. E.; Sonnenfeld, A.; Spiniello, C.; Van de Vyvere, L.
I: Astronomy & Astrophysics, Bind 639, A101, 16.07.2020.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - TDCOSMO
T2 - I. An exploration of systematic uncertainties in the inference of H-0 from time-delay cosmography
AU - Millon, M.
AU - Galan, A.
AU - Courbin, F.
AU - Treu, T.
AU - Suyu, S. H.
AU - Ding, X.
AU - Birrer, S.
AU - Chen, G. C-F
AU - Shajib, A. J.
AU - Sluse, D.
AU - Wong, K. C.
AU - Agnello, A.
AU - Auger, M. W.
AU - Buckley-Geer, E. J.
AU - Chan, J. H. H.
AU - Collett, T.
AU - Fassnacht, C. D.
AU - Hilbert, S.
AU - Koopmans, L. V. E.
AU - Motta, Francis
AU - Mukherjee, S.
AU - Rusu, C. E.
AU - Sonnenfeld, A.
AU - Spiniello, C.
AU - Van de Vyvere, L.
PY - 2020/7/16
Y1 - 2020/7/16
N2 - 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, and 3- the deflector mass model. To meet this goal in a quantitative way, we reproduced the H0LiCOW/SHARP/STRIDES (hereafter TDCOSMO) procedures on a set of real and simulated data, and we find the following. First, stellar kinematics cannot be a dominant source of error or bias since we find that a systematic change of 10% of measured velocity dispersion leads to only a 0.7% shift on H-0 from the seven lenses analyzed by TDCOSMO. Second, we find no bias to arise 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 that 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 and accurately by both models. If the two models disagree, as in the case of some pathological models illustrated here, the TDCOSMO procedure either discriminates between them through the goodness of fit, or it accounts for the discrepancy in the final error bars provided by the analysis. This conclusion is consistent with a reanalysis of six of the TDCOSMO (real) lenses: the composite model yieldsH-0 = 74.0(-1.8)(+1.7) km s(-1) Mpc(-1)H 0= 74 .0- 1.8+ 1.7kms- 1-Mpc- 1, while the power-law model yields74.2(-1.6)(+1.6) km s(-1) Mpc(-1)74 .2- 1.6+ 1.6kms- 1-Mpc- 1. In conclusion, we find no evidence of bias or errors larger than the current statistical uncertainties reported by TDCOSMO.
AB - 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, and 3- the deflector mass model. To meet this goal in a quantitative way, we reproduced the H0LiCOW/SHARP/STRIDES (hereafter TDCOSMO) procedures on a set of real and simulated data, and we find the following. First, stellar kinematics cannot be a dominant source of error or bias since we find that a systematic change of 10% of measured velocity dispersion leads to only a 0.7% shift on H-0 from the seven lenses analyzed by TDCOSMO. Second, we find no bias to arise 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 that 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 and accurately by both models. If the two models disagree, as in the case of some pathological models illustrated here, the TDCOSMO procedure either discriminates between them through the goodness of fit, or it accounts for the discrepancy in the final error bars provided by the analysis. This conclusion is consistent with a reanalysis of six of the TDCOSMO (real) lenses: the composite model yieldsH-0 = 74.0(-1.8)(+1.7) km s(-1) Mpc(-1)H 0= 74 .0- 1.8+ 1.7kms- 1-Mpc- 1, while the power-law model yields74.2(-1.6)(+1.6) km s(-1) Mpc(-1)74 .2- 1.6+ 1.6kms- 1-Mpc- 1. In conclusion, we find no evidence of bias or errors larger than the current statistical uncertainties reported by TDCOSMO.
KW - gravitational lensing: strong
KW - methods: data analysis
KW - EARLY-TYPE GALAXIES
KW - POWER-LAW MODELS
KW - LENS ACS SURVEY
KW - HUBBLE CONSTANT
KW - DENSITY PROFILES
KW - COSMIC EVOLUTION
KW - MASS FUNCTION
KW - STELLAR MASS
KW - DEGENERACIES
KW - DYNAMICS
U2 - 10.1051/0004-6361/201937351
DO - 10.1051/0004-6361/201937351
M3 - Journal article
VL - 639
JO - Astronomy & Astrophysics
JF - Astronomy & Astrophysics
SN - 0004-6361
M1 - A101
ER -
ID: 246869157