Seminario DAS: A Giant Arc on the Sky

Speaker: Alexia M. Lopez PhD student Jeremiah Horrocks Institute, University of Central Lancashire UK

Abstract: The Giant Arc (GA) is a recent large-scale structure (LSS) discovery made via intervening MgII absorbers in the spectra of background quasars. The GA spans ~1Gpc at redshift ~0.8 and appears to be almost symmetrical on the sky. Three statistical tests are applied to the GA (single-linkage hierarchical clustering/convex hull of member spheres, power spectrum analysis and Cuzick-Edwards test) and we find for each test the GA and GA field is overdense and clustered >3 sigma. The GA has interesting properties following visual inspection of the redshift distribution and equivalent width distribution of the MgII absorbers. The GA poses a potential challenge to the cosmological principle on which the standard model of cosmology is founded.

Diego Mardones
Seminar Coordinator
DAS/UChile - diego@das.uchile.cl