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arXiv · 2404.08033

Imaging dark matter at the smallest scales with $z\approx1$ lensed stars

J. M. Diego·Sung Kei Li·Alfred Amruth·Ashish K. Meena·Tom J. Broadhurst·Patrick L. Kelly·Alexei V. Filippenko·Liliya L. R. Williams·Adi Zitrin·William E. Harris·Marta Reina-Campos·Carlo Giocoli·Liang Dai·Mitchell F. Struble·Tommaso Treu·Yoshinobu Fudamoto·Daniel Gilman·Anton M. Koekemoer·Jeremy Lim·J. M. Palencia·Fengwu Sun·Rogier A. Windhorst
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Abstract

Observations of caustic-crossing galaxies at redshift $0.7 2$ 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).

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BibTeXRIS

J. M. Diego, Sung Kei Li, Alfred Amruth, Ashish K. Meena, Tom J. Broadhurst, Patrick L. Kelly, Alexei V. Filippenko, Liliya L. R. Williams, Adi Zitrin, William E. Harris, Marta Reina-Campos, Carlo Giocoli, Liang Dai, Mitchell F. Struble, Tommaso Treu, Yoshinobu Fudamoto, Daniel Gilman, Anton M. Koekemoer, Jeremy Lim, J. M. Palencia, Fengwu Sun, Rogier A. Windhorst. 2024-04-11. Imaging dark matter at the smallest scales with $z\approx1$ lensed stars. https://doi.org/10.1051/0004-6361/202450474

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