We present a second-order calculation of relativistic large-scale-structure observables in cosmological perturbation theory, specifically the "cosmic rulers and clock", which are the building-blocks of any other large-scale-structure observable, including galaxy number counts, on large scales. We calculate the scalar rulers (longitudinal perturbation and magnification) and the cosmic clock to...
Low-mass dark matter halos perturb the Einstein rings of strong gravitational lenses. By means of high-resolution imaging and precision modeling, we can directly measure the masses, abundances, and internal density profiles of these halos. In this talk I will present a systematic overview of our multi-year effort to detect dark subhalos: from the development of the PyAutoLens software suite,...
Assembly bias, which is variations in clustering at fixed halo mass due to differences in halo formation history, is challenging to detect observationally. We investigate a stellar mass–dependent assembly bias using a large sample of massive galaxy clusters with spectroscopically confirmed brightest cluster galaxies (BCGs). Combining galaxy–galaxy lensing and projected correlation function...
The tidal field of the host halo strips not only the dark matter of the subhalo but also its embedded satellite galaxies. This process alters the stellar-mass–halo-mass relation for satellites compared to isolated galaxies. The co-evolution of stellar and dark matter components determines the fate of the faintest galaxies: will they be disrupted along with their host subhalo, or survive as...
Dark matter is proposed to dominate the mass-energy content of the Universe, and its nature can be studied via large-scale structure probes, such as the unresolved gamma-ray background (UGRB) using cosmological methods. We investigate the cross-correlation between energy-binned intensity maps of the UGRB from 15 years of Fermi-LAT data and tomographic weak gravitational lensing data from the...
