Gravitational Arc Tomography

The ARCTOMO collaboration, led by Prof. Sebastián López (U. Chile), is a team of astronomers from several institutions from Chile and the world dedicated to the study of the circumgalactic medium of galaxies using the “gravitational arc tomography” technique.

Rationale (taken from ARCTOMO website)
Ninety percent of normal matter in the Universe is in gaseous form whereas luminous matter (stars) only account for 10% of the atoms. In ARCTOMO we seek to advance the frontier of knowledge in galaxy evolution by deciphering observationally the role of this diffuse gas in galaxy evolution (a.k.a., the cosmic baryon cycle of galaxies). Specifically, we want to establish for the first time the spatial and kinematical structure of the absorbing circumgalactic medium (CGM) around intermediate-redshift galaxies combining observations from the traditional quasar absorption line technique with those from our novel gravitational-arc tomography.

Giant gravitational arcs can extend over up to a few 100 kpc on the sky at intervening redshifts z~1, thus offering a unique opportunity to probe the CGM of intervening absorbers. In ARCTOMO we work with IFU and echelle observations of some of the brightest arcs known, designed to map the spatial and kinematic distribution of the cool CGM at z~1. These novel observations offer new and independent boundary conditions to models and simulations.

Role of AGATHA team members within ARCTOMO: Dr. Jorge González and Manuel Solimano have contributed to the project by looking at the cold gas of the background and intervening galaxies using submm facilities such as ALMA. The cold gas and dust reservoirs in galaxies represent a key phase of the baryon cycle, since they provide the immediate fuel for star formation. In this sense, the observations led by Jorge González and Manuel Solimano offer a view of condensed gas that may once have been in the diffuse phase probed by arc-tomography.


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