PASSAGES

The goal of the Lensing focus group is to coordinate efforts for developing, testing, and comparing various gravitational lens models for the PASSAGES objects. With these modeling efforts, intrinsic properties of the lensed objects may be inferred, and magnifications may be derived for different wavelengths and tracers, enabling a clearer comparison of the sample with unlensed objects. This lens modeling campaign also offers opportunities for studying the foreground lensing population. Various modeling approaches will be employed (e.g. Lenstool, pyautolens, light-traces-mass models) to ensure the robustness of results, and to benefit from the advantages of each method.

Empirically, the most active time in the Universe for galaxy growth and evolution occurred between redshift, z=1-3, with a peak in galaxy merger rates, supermassive black hole accretion rates and star formation rates. The goal of this working group is to characterize the chemical and thermodynamic properties of the interstellar medium (ISM), while probing the role in which (dust-obscured) active galactic nuclei may play in the growth of their host.

Strong lensing magnification makes it possible to extend the limits of locally derived spectral/photometric diagnostics to higher redshifts. Although Carbon monoxide (CO) is the most abundant molecule aside from H2 and is often used,  the amplification of these PASSAGES objects enable high signal-to-noise experiments to detect and model the variety of other atomic and molecular species for a diverse, multi-wavelength characterization of individual galaxies in the early Universe. This group aims to use state-of-the-art high spectro-spatial resolution to better understand the elusive, yet dominant, role of star formation processes beyond redshift, z>1. 

Galaxy overdensities/protoclusters and strongly-lensed galaxies are both detected by their rest-frame far infrared colors. We refer to a group of galaxies that has a high projected number density of galaxies by the more general term of "galaxy overdensity," and we refer to a group of galaxies that will evolve into a galaxy cluster at later cosmic times as a "protocluster." Some of the outstanding questions that our team is investigating are: how do massive galaxy overdensities and protoclusters form? What are the physical attributes of protoclusters?  What drives the high star formation rates that characterize some galaxy overdensities? Which physical processes govern the truncation of star forming gas and the development of a hot dark matter halo in galaxy overdensities? Can we come to a consensus of the current census of bona fide protoclusters?