Highly Magnified Cosmological Sources in Galaxy Cluster Lenses

2020-01-30
12:00
UB
DAM Seminar (724, ICCUB building, UB Campus)
Highly Magnified Cosmological Sources in Galaxy Cluster Lenses
Individual luminous stars or compact star-forming complexes in distant galaxies have been observed by the Hubble Space Telescope in the field of strong lensing massive galaxy clusters. These sources are fortuitously located in the proximity of the lensing caustic and are tremendously magnified by factors in the hundreds or larger.

Nominally having a sub-critical surface density, intracluster stars are in fact optically thick of microlensing in the presence of nearly critical macro convergence and shear, a situation pertinent to those highly magnified sources. In addition, highly magnified sources are the most sensitive, both photometrically and astrometrically, to the perturbing effects of intracluster substructure lenses such as sub-galactic subhalos expected from the cold dark matter theory.

I will introduce the latest theoretical and observational progress in understanding the phenomenology of highly magnified sources in the high redshift universe. I will discuss how this newly studied phenomenon can be exploited to probe the dark matter structure on small scales inside the galaxy cluster halo.

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