Seminarium Zakładu Astrofizyki

Galaxy mergers underpin our current understanding of how galaxies grow and evolve. In the current CDM models, dark matter halos merge hierarchically resulting in the collision between their baryonic counterparts. During these mergers the galaxies are disrupted, with the tidal forces twisting and distorting them, moving the stars, dust and gas and changing morphologies. This movement of material can also trigger extreme events, with gas pushed into the centre of the galaxies triggering active galactic nuclei and the compression of the gas triggering periods of intense star formation.

Galaxies are constantly fed by the diffuse material from the intergalactic medium through the Circum-Galactic Medium (CGM).We can probe these vast gaseous halos around galaxies by studying absorbers detected in the spectra of bright background quasars. To understand the dynamics of the system we combine the physical properties from the absorption features with the broader view of the absorber’s host and its environment by emission diagnostics, using IFU spectroscopy.

When the Universe was adolescent (at a redshift of z ≈ 2), it contained a large density of very massive galaxies with intense star formation activity. This epoch of the Universe in particular, also known as the cosmic noon, marks the peak of the star formation rate density.

The most prominent spectral features of quasars, as observed in optics and UV, are broad emission lines. Over development of knowledge importance of those features has increased. Recently, spectral
variability became useful in the field of cosmology. We still need deeper understanding of physics behind emitting spectra to improve quality of the measurements. I am going to present concepts used in the interpretation of the optical/UV observations and models/simulations aimed at reproducing spectra. I will briefly put proposed scenarios in the context of evolution.