Recent works have shown that weak lensing magnification must be included in upcoming large-scale structure analyses, such as for the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), to avoid biasing the cosmological results. In this work, we investigate whether including magnification has a positive impact on the precision of the cosmological constraints, as well as being necessary to avoid bias. We forecast this using an LSST mock catalogue and a halo model to calculate the galaxy power spectra. We find that including magnification has little effect on the precision of the cosmological parameter constraints for an LSST galaxy clustering analysis, where the halo model parameters are additionally constrained by the galaxy luminosity function. In particular, we find that for the LSST gold sample (i < 25.3) including weak lensing magnification only improves the galaxy clustering constraint on Ωm by a factor of 1.03, and when using a very deep LSST mock sample (i < 26.5) by a factor of 1.3. Since magnification predominantly contributes to the clustering measurement and provides similar information to that of cosmic shear, this improvement would be reduced for a combined galaxy clustering and shear analysis. We also confirm that not modelling weak lensing magnification will catastrophically bias the cosmological results from LSST. Magnification must therefore be included in LSST large-scale structure analyses even though it does not significantly enhance the precision of the cosmological constraints.
Mahony, Constance, et al. "Forecasting the potential of weak lensing magnification to enhance LSST large-scale structure analyses." Monthly Notices of the Royal Astronomical Society, vol. 513, no. 1, Mar. 2022. https://doi.org/10.1093/mnras/stac872
Mahony, Constance, Fortuna, Maria Cristina, Joachimi, Benjamin, et al., "Forecasting the potential of weak lensing magnification to enhance LSST large-scale structure analyses," Monthly Notices of the Royal Astronomical Society 513, no. 1 (2022), https://doi.org/10.1093/mnras/stac872
@article{osti_1865510,
author = {Mahony, Constance and Fortuna, Maria Cristina and Joachimi, Benjamin and Korn, Andreas and Hoekstra, Henk and Schmidt, Samuel J. and Alonso, David and Singh, Sukhdeep and Ricci, Marina and Hildebrandt, Hendrik and others},
title = {Forecasting the potential of weak lensing magnification to enhance LSST large-scale structure analyses},
annote = {ABSTRACT Recent works have shown that weak lensing magnification must be included in upcoming large-scale structure analyses, such as for the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST), to avoid biasing the cosmological results. In this work, we investigate whether including magnification has a positive impact on the precision of the cosmological constraints, as well as being necessary to avoid bias. We forecast this using an LSST mock catalogue and a halo model to calculate the galaxy power spectra. We find that including magnification has little effect on the precision of the cosmological parameter constraints for an LSST galaxy clustering analysis, where the halo model parameters are additionally constrained by the galaxy luminosity function. In particular, we find that for the LSST gold sample (i < 25.3) including weak lensing magnification only improves the galaxy clustering constraint on Ωm by a factor of 1.03, and when using a very deep LSST mock sample (i < 26.5) by a factor of 1.3. Since magnification predominantly contributes to the clustering measurement and provides similar information to that of cosmic shear, this improvement would be reduced for a combined galaxy clustering and shear analysis. We also confirm that not modelling weak lensing magnification will catastrophically bias the cosmological results from LSST. Magnification must therefore be included in LSST large-scale structure analyses even though it does not significantly enhance the precision of the cosmological constraints.},
doi = {10.1093/mnras/stac872},
url = {https://www.osti.gov/biblio/1865510},
journal = {Monthly Notices of the Royal Astronomical Society},
issn = {ISSN 0035-8711},
number = {1},
volume = {513},
place = {United Kingdom},
publisher = {Oxford University Press},
year = {2022},
month = {03}}
Monthly Notices of the Royal Astronomical Society, Journal Name: Monthly Notices of the Royal Astronomical Society Journal Issue: 1 Vol. 513; ISSN 0035-8711