gravitational lensing: strong; methods: data analysis; Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract :
[en] Time-delay cosmography of lensed quasars has achieved 2.4% precision on the measurement of the Hubble constant, H[SUB]0[/SUB]. 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[SUB]0[/SUB] 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[SUB]0[/SUB] 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[SUB]0[/SUB] 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 yields H[SUB]0[/SUB] = 74.0[SUB]-1.8[/SUB][SUP]+1.7[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP], while the power-law model yields 74.2[SUB]-1.6[/SUB][SUP]+1.6[/SUP] km s[SUP]-1[/SUP] Mpc[SUP]-1[/SUP]. In conclusion, we find no evidence of bias or errors larger than the current statistical uncertainties reported by TDCOSMO.
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Millon, M.; Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290, Versoix, Switzerland
Galan, A.; Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290, Versoix, Switzerland
Courbin, F.; Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290, Versoix, Switzerland
Treu, T.; Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
Suyu, S. H.; Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748, Garching, Germany ; Physik-Department, Technische Universität München, James-Franck-Straße 1, 85748, Garching, Germany ; Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), 11F of ASMAB, No.1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan
Ding, X.; Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
Birrer, S.; Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Stanford, CA, 94305, USA
Chen, G. C.-F.; Department of Physics, University of California, Davis, CA, 95616, USA
Shajib, A. J.; Department of Physics and Astronomy, University of California, Los Angeles, CA, 90095, USA
Sluse, Dominique ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Wong, K. C.; Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba, 277-8583, Japan
Agnello, A.; Niels Bohr Institute > DARK
Auger, M. W.; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK ; Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK
Buckley-Geer, E. J.; Fermi National Accelerator Laboratory, PO Box 500, Batavia, IL, 60510, USA
Chan, J. H. H.; Institute of Physics, Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290, Versoix, Switzerland
Collett, T.; University of Portsmouth, Institute of Cosmology and Gravitation, Portsmouth, PO1 3FX, UK
Fassnacht, C. D.; Department of Physics, University of California, Davis, CA, 95616, USA
Hilbert, S.; Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85748, Garching, Germany
Koopmans, L. V. E.; Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV, Groningen, The Netherlands
Motta, V.; Instituto de Física y Astronomía, Facultad de Ciencias, Universidad de Valparaíso, Avda. Gran Bretaña 1111, Valparaíso, Chile
Mukherjee, Sampath ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Labo de physique atmosphérique et planétaire (LPAP)
Rusu, C. E.; National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
Sonnenfeld, A.; Leiden Observatory, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, The Netherlands
Van de Vyvere, Lyne ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
