Kinematic Lensing with the Roman Space Telescope

Jiachuan Xu; Tim Eifler; Eric Huff; Pranjal R. S.; Hung-Jin Huang; Spencer Everett; Elisabeth Krause

doi:10.1093/mnras/stac3685

paper

Kinematic Lensing with the Roman Space Telescope

arXiv:2201.00739 · doi:10.1093/mnras/stac3685

Abstract

Kinematic lensing (KL) is a new cosmological measurement technique that combines traditional weak lensing (WL) shape measurements of disc galaxies with their kinematic information. Using the Tully-Fisher relation KL breaks the degeneracy between intrinsic and observed ellipticity and significantly reduces the impact of multiple systematics that are present in traditional WL. We explore the performance of KL given the instrument capabilities of the $Roman Space Telescope$ , assuming overlap of the High Latitude Imaging Survey (HLIS), the High Latitude Spectroscopy Survey (HLSS) over 2,000 deg $^{2}$ . Our KL suitable galaxy sample has a number density of $n_{gal} = 4 arcmin^{- 1}$ with an estimated shape noise level of $σ_{ε} = 0.035$ . We quantify the cosmological constraining power on $Ω_{m}$ - $S_{8}$ , $w_{p}$ - $w_{a}$ by running simulated likelihood analyses that account for redshift and shear calibration uncertainties, intrinsic alignment and baryonic feedback. Compared to a traditional WL survey we find that KL significantly improves the constraining power on $Ω_{m}$ - $S_{8}$ (FoM $_{KL}$ =1.70FoM $_{WL}$ ) and $w_{p}$ - $w_{a}$ (FoM $_{KL}$ =3.65FoM $_{WL}$ ). We also explore a "narrow tomography KL survey" using 30 instead of the default 10 tomographic bins, however we find no meaningful enhancement to the FoM even when assuming a significant time-dependence in our fiducial dark energy input scenarios.

Kinematic Lensing with the Roman Space Telescope

Abstract

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