Ponente
Descripción
Submillimetre galaxies (SMGs) are exceptional background sources for magnification‑bias studies, but the inherently limited sky coverage in the submillimetre band constrains their statistical power. Beyond H‑ATLAS, Herschel has produced additional submm catalogues, although not optimised for statistical lensing analyses.
Our goal is to enhance the cosmological constraints derived from SMG magnification bias by exploiting the full submm sky surveyed by Herschel.
We augmented the SMG sample by incorporating other Herschel catalogues that overlap with SDSS spectroscopic lens samples. Random catalogues were generated via kernel density estimation to compute the cross‑correlation functions . Markov Chain Monte Carlo techniques were then employed to extract both astrophysical and cosmological parameters for each individual catalogue and for the combined dataset.
Individual Herschel catalogues yield reasonable central values for $\Omega_M$ and $\sigma_8$ but suffer from large uncertainties. The combined analysis—dominated by the statistically superior H‑ATLAS dataset—nonetheless improves precision sufficiently to place for the first time a full constraint on the Hubble parameter, finding $\Omega_M = 0.25^{+0.03}_{-0.05}, \sigma_8 = 0.74^{+0.06}_{-0.05}, h = 0.74^{+0.11}_{-0.20}$.
Submillimetre galaxies (SMGs) prove to be excellent background sources for magnification bias, but the limited sky coverage in the submillimetre remains a major constraint. Wider surveys specifically designed for lensing would make it possible to probe larger angular scales via cross‑correlation, ultimately delivering more competitive constraints. In that context, magnification bias could become an independent and complementary probe in cosmological analyses.
