Direct shear mapping - a new weak lensing tool
We have developed a new technique called direct shear mapping (DSM) to measure gravitational lensing shear directly from observations of a single background source. The technique assumes the velocity map of an unlensed, stably rotating galaxy will be rotationally symmetric. Lensing distorts the velo...
Published in: | Monthly Notices of the Royal Astronomical Society |
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Oxford University Press
2015
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Online Access: | http://hdl.handle.net/1959.3/412118 https://doi.org/10.1093/mnras/stv1083 |
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ftswinburne:tle:87b3849d-89c2-4f51-aa7f-5e4ec34b47d6:28f49f06-0da8-44be-9edc-ad1dd0a9c582:1 2023-05-15T18:12:49+02:00 Direct shear mapping - a new weak lensing tool De Burgh-Day, C. O. Taylor, E. N. Webster, R. L. Hopkins, A. M. Swinburne University of Technology 2015 http://hdl.handle.net/1959.3/412118 https://doi.org/10.1093/mnras/stv1083 unknown Oxford University Press http://hdl.handle.net/1959.3/412118 https://doi.org/10.1093/mnras/stv1083 This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Monthly Notices of the Royal Astronomical Society, Vol. 451, no. 2 (2015), pp. 2161-2173 Journal article 2015 ftswinburne https://doi.org/10.1093/mnras/stv1083 2019-09-07T22:03:12Z We have developed a new technique called direct shear mapping (DSM) to measure gravitational lensing shear directly from observations of a single background source. The technique assumes the velocity map of an unlensed, stably rotating galaxy will be rotationally symmetric. Lensing distorts the velocity map making it asymmetric. The degree of lensing can be inferred by determining the transformation required to restore axisymmetry. This technique is in contrast to traditional weak lensing methods, which require averaging an ensemble of background galaxy ellipticity measurements, to obtain a single shear measurement. We have tested the efficacy of our fitting algorithm with a suite of systematic tests on simulated data. We demonstrate that we are in principle able to measure shears as small as 0.01. In practice, we have fitted for the shear in very low redshift (and hence unlensed) velocity maps, and have obtained null result with an error of ±0.01. This high-sensitivity results from analysing spatially resolved spectroscopic images (i.e. 3D data cubes), including not just shape information (as in traditional weak lensing measurements) but velocity information as well. Spirals and rotating ellipticals are ideal targets for this new technique. Data from any large Integral Field Unit (IFU) or radio telescope is suitable, or indeed any instrument with spatially resolved spectroscopy such as the Sydney-Australian-Astronomical Observatory Multi-Object Integral Field Spectrograph (SAMI), the Atacama Large Millimeter/submillimeter Array (ALMA), the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) and the Square Kilometer Array (SKA). Article in Journal/Newspaper sami Swinburne University of Technology: Swinburne Research Bank Monthly Notices of the Royal Astronomical Society 451 2 2161 2173 |
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Swinburne University of Technology: Swinburne Research Bank |
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ftswinburne |
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description |
We have developed a new technique called direct shear mapping (DSM) to measure gravitational lensing shear directly from observations of a single background source. The technique assumes the velocity map of an unlensed, stably rotating galaxy will be rotationally symmetric. Lensing distorts the velocity map making it asymmetric. The degree of lensing can be inferred by determining the transformation required to restore axisymmetry. This technique is in contrast to traditional weak lensing methods, which require averaging an ensemble of background galaxy ellipticity measurements, to obtain a single shear measurement. We have tested the efficacy of our fitting algorithm with a suite of systematic tests on simulated data. We demonstrate that we are in principle able to measure shears as small as 0.01. In practice, we have fitted for the shear in very low redshift (and hence unlensed) velocity maps, and have obtained null result with an error of ±0.01. This high-sensitivity results from analysing spatially resolved spectroscopic images (i.e. 3D data cubes), including not just shape information (as in traditional weak lensing measurements) but velocity information as well. Spirals and rotating ellipticals are ideal targets for this new technique. Data from any large Integral Field Unit (IFU) or radio telescope is suitable, or indeed any instrument with spatially resolved spectroscopy such as the Sydney-Australian-Astronomical Observatory Multi-Object Integral Field Spectrograph (SAMI), the Atacama Large Millimeter/submillimeter Array (ALMA), the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) and the Square Kilometer Array (SKA). |
author2 |
Swinburne University of Technology |
format |
Article in Journal/Newspaper |
author |
De Burgh-Day, C. O. Taylor, E. N. Webster, R. L. Hopkins, A. M. |
spellingShingle |
De Burgh-Day, C. O. Taylor, E. N. Webster, R. L. Hopkins, A. M. Direct shear mapping - a new weak lensing tool |
author_facet |
De Burgh-Day, C. O. Taylor, E. N. Webster, R. L. Hopkins, A. M. |
author_sort |
De Burgh-Day, C. O. |
title |
Direct shear mapping - a new weak lensing tool |
title_short |
Direct shear mapping - a new weak lensing tool |
title_full |
Direct shear mapping - a new weak lensing tool |
title_fullStr |
Direct shear mapping - a new weak lensing tool |
title_full_unstemmed |
Direct shear mapping - a new weak lensing tool |
title_sort |
direct shear mapping - a new weak lensing tool |
publisher |
Oxford University Press |
publishDate |
2015 |
url |
http://hdl.handle.net/1959.3/412118 https://doi.org/10.1093/mnras/stv1083 |
genre |
sami |
genre_facet |
sami |
op_source |
Monthly Notices of the Royal Astronomical Society, Vol. 451, no. 2 (2015), pp. 2161-2173 |
op_relation |
http://hdl.handle.net/1959.3/412118 https://doi.org/10.1093/mnras/stv1083 |
op_rights |
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
op_doi |
https://doi.org/10.1093/mnras/stv1083 |
container_title |
Monthly Notices of the Royal Astronomical Society |
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451 |
container_issue |
2 |
container_start_page |
2161 |
op_container_end_page |
2173 |
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1766185307341848576 |