http://arxiv.org/abs/2203.09865
Using data from the Pantheon SN Ia compilation and the Sloan Digital Sky Survey (SDSS), we propose an estimator for weak lensing convergence incorporating positional and photometric data of foreground galaxies. The correlation between this and the Hubble diagram residuals of the supernovae is $3.7\sigma$, consistent with weak lensing magnification due to dark matter halos centered on galaxies. We additionally constrain the properties of the galactic haloes, such as the mass-to-light ratio $\Gamma$ and radial profile of the halo matter density $\rho(r)$. We derive a new relationship for the additional r.m.s. scatter in magnitudes caused by lensing, finding $\sigma_{\rm lens} = (0.06 \pm 0.017) (d_{\rm M}(z)/ d_{\rm M}(z=1))^{3/2}$ where $d_{\rm M}(z)$ is the comoving distance to redshift $z$. We therefore find that the scatter in flux caused by lensing will be of a similar size as the intrinsic scatter (after standardisation of the magnitude) of modern SN Ia surveys by $z \sim 1.2$, which is closer than generally assumed. We propose a modification of the distance modulus estimator for SN Ia to incorporate lensing, which we anticipate will improve the accuracy of cosmological parameter estimation using high-redshift SN Ia data.
P. Shah, P. Lemos and O. Lahav
Mon, 21 Mar 22
20/60
Comments: Submitted to MNRAS for publication. Comments welcome
You must be logged in to post a comment.