2013A&A...559A..37S


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST02:32:41

2013A&A...559A..37S - Astronomy and Astrophysics, volume 559A, 37-37 (2013/11-1)

Mass-sheet degeneracy, power-law models and external convergence: Impact on the determination of the Hubble constant from gravitational lensing.

SCHNEIDER P. and SLUSE D.

Abstract (from CDS):

The light travel time differences in strong gravitational lensing systems allows an independent determination of the Hubble constant. This method has been successfully applied to several lens systems. The formally most precise measurements are, however, in tension with the recent determination of H0 from the Planck satellite for a spatially flat six-parameters ΛCDM cosmology. We reconsider the uncertainties of the method, concerning the mass profile of the lens galaxies, and show that the formal precision relies on the assumption that the mass profile is a perfect power law. Simple analytical arguments and numerical experiments reveal that mass-sheet like transformations yield significant freedom in choosing the mass profile, even when exquisite Einstein rings are observed. Furthermore, the characterization of the environment of the lens does not break that degeneracy which is not physically linked to extrinsic convergence. We present an illustrative example where the multiple imaging properties of a composite (baryons + dark matter) lens can be extremely well reproduced by a power-law model having the same velocity dispersion, but with predictions for the Hubble constant that deviate by ∼20%. Hence we conclude that the impact of degeneracies between parametrized models have been underestimated in current H0 measurements from lensing, and need to be carefully reconsidered.

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Journal keyword(s): cosmological parameters - gravitational lensing: strong

Simbad objects: 8

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Number of rows : 8

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 [VV2006] J043814.8-122314 QSO 04 38 14.88 -12 17 14.6     17.15     ~ 170 2
2 [IBB2003] SDSS J0924+0219 gLS 09 24 55.80 +02 19 24.8           ~ 15 0
3 QSO J0924+0219 QSO 09 24 55.8048 +02 19 24.850   18.58 18.36     ~ 109 1
4 SDSS J094656.68+100652.8 G 09 46 56.681 +10 06 52.80     17.78   17.09 ~ 30 0
5 7C 095757.60+560823.00 QSO 10 01 20.6915852239 +55 53 55.595776916   17.16 16.95     ~ 697 3
6 QSO J1131-1231 QSO 11 31 51.5387 -12 31 58.716           ~ 205 1
7 NVSS J160914+653229 rG 16 09 13.96 +65 32 28.8     19.4     ~ 185 1
8 ACO 2261 ClG 17 22 28.3 +32 09 13           ~ 283 0

    Equat.    Gal    SGal    Ecl

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2020.07.04-02:32:41

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