학술논문

Imaging dark matter at the smallest scales with $z\approx1$ lensed stars
Document Type
Working Paper
Source
Subject
Astrophysics - Cosmology and Nongalactic Astrophysics
Astrophysics - Astrophysics of Galaxies
Astrophysics - Solar and Stellar Astrophysics
Language
Abstract
Observations of caustic-crossing galaxies at redshift $0.72$ and the number density of events is greater around substructureand the number density of events is greater around substructures, and (ii) negative imaging regime where $\beta<2$. We study the particular case of seven microlensing events found by HST in the Dragon arc (at z=0.725). We find that a population of supergiant stars with a steep LF with $\beta=2.55$ fits the distribution of these events. We identify a small region of high density of microlensing events, and interpret it as evidence of a possible invisible substructure, for which we derive a mass of $\sim 1.3 \times 10^8\,\Msun$ (within its Einstein radius).
Comment: 23 pages, 16 figures