Testing Velocity-field Lensing on IllustrisTNG Galaxies
Weak gravitational lensing shear could be measured far more precisely if information about unlensed attributes of source galaxies were available. Disk galaxy velocity fields supply such information, at least in principle, with idealized models predicting orders of magnitude more Fisher information w...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/acbb70 |
| _version_ | 1797697172932657152 |
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| author | Jean Donet David Wittman |
| author_facet | Jean Donet David Wittman |
| author_sort | Jean Donet |
| collection | DOAJ |
| description | Weak gravitational lensing shear could be measured far more precisely if information about unlensed attributes of source galaxies were available. Disk galaxy velocity fields supply such information, at least in principle, with idealized models predicting orders of magnitude more Fisher information when velocity-field observations are used to complement images. To test the level at which realistic features of disk galaxies (warps, bars, spiral arms, and other substructure) inject noise or bias into such shear measurements, we fit an idealized disk model, including shear, to unsheared galaxies in the Illustris TNG100 simulation. The inferred shear thus indicates the extent to which unmodeled galaxy features inject noise and bias. We find that γ _+ , the component of shear parallel to the galaxy’s first principal axis, is highly biased and noisy because disks violate the assumption of face-on circularity, displaying a range of intrinsic axis ratios (0.85 ± 0.11). The other shear component, γ _× , shows little bias and is well-described by a double Gaussian distribution with central core scatter σ _core ≈ 0.03, with low-amplitude, broad wings. This is the first measurement of the natural noise floor in the proposed velocity-field lensing technique. We conclude that the technique will achieve impressive precision gains for measurements of γ _× , but little gain for measurements of γ _+ . |
| first_indexed | 2024-03-12T03:36:28Z |
| format | Article |
| id | doaj.art-2dbfa9acf018471e96975bee5c511a6a |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:36:28Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-2dbfa9acf018471e96975bee5c511a6a2023-09-03T13:08:56ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0194528810.3847/1538-4357/acbb70Testing Velocity-field Lensing on IllustrisTNG GalaxiesJean Donet0David Wittman1https://orcid.org/0000-0002-0813-5888Department of Physics & Astronomy, University of California , Davis, CA 95616, USA ; dwittman@physics.ucdavis.eduDepartment of Physics & Astronomy, University of California , Davis, CA 95616, USA ; dwittman@physics.ucdavis.eduWeak gravitational lensing shear could be measured far more precisely if information about unlensed attributes of source galaxies were available. Disk galaxy velocity fields supply such information, at least in principle, with idealized models predicting orders of magnitude more Fisher information when velocity-field observations are used to complement images. To test the level at which realistic features of disk galaxies (warps, bars, spiral arms, and other substructure) inject noise or bias into such shear measurements, we fit an idealized disk model, including shear, to unsheared galaxies in the Illustris TNG100 simulation. The inferred shear thus indicates the extent to which unmodeled galaxy features inject noise and bias. We find that γ _+ , the component of shear parallel to the galaxy’s first principal axis, is highly biased and noisy because disks violate the assumption of face-on circularity, displaying a range of intrinsic axis ratios (0.85 ± 0.11). The other shear component, γ _× , shows little bias and is well-described by a double Gaussian distribution with central core scatter σ _core ≈ 0.03, with low-amplitude, broad wings. This is the first measurement of the natural noise floor in the proposed velocity-field lensing technique. We conclude that the technique will achieve impressive precision gains for measurements of γ _× , but little gain for measurements of γ _+ .https://doi.org/10.3847/1538-4357/acbb70Gravitational lensingGravitational lensing shearWeak gravitational lensingGalaxy kinematicsMagnetohydrodynamical simulations |
| spellingShingle | Jean Donet David Wittman Testing Velocity-field Lensing on IllustrisTNG Galaxies The Astrophysical Journal Gravitational lensing Gravitational lensing shear Weak gravitational lensing Galaxy kinematics Magnetohydrodynamical simulations |
| title | Testing Velocity-field Lensing on IllustrisTNG Galaxies |
| title_full | Testing Velocity-field Lensing on IllustrisTNG Galaxies |
| title_fullStr | Testing Velocity-field Lensing on IllustrisTNG Galaxies |
| title_full_unstemmed | Testing Velocity-field Lensing on IllustrisTNG Galaxies |
| title_short | Testing Velocity-field Lensing on IllustrisTNG Galaxies |
| title_sort | testing velocity field lensing on illustristng galaxies |
| topic | Gravitational lensing Gravitational lensing shear Weak gravitational lensing Galaxy kinematics Magnetohydrodynamical simulations |
| url | https://doi.org/10.3847/1538-4357/acbb70 |
| work_keys_str_mv | AT jeandonet testingvelocityfieldlensingonillustristnggalaxies AT davidwittman testingvelocityfieldlensingonillustristnggalaxies |