We also measure the shape of the gas around the galaxies at the redshift at which the stars start to form aligned with the disc, and find that the mayor axis of gas tend to be closer to be perpendicular to the angular momentum of the stars for bulgeless galaxies than for normal spirals.

We also notice that the velocity dispersion perpendicular to the disc is lower for bulgeless galaxies than to their counterpart, and has been low for a longer period of time. We notice that the bulgeless galaxies have been forming stars aligned with the disc for longer times than for other galaxies. However, apparently the most important factor that differentiates the formation of bulgeless is the alignment of the gas reservoir and how long stars have formed from this aligned gas. We notice some differences in the age of the stellar content, sSFR and merger ratio between bulgeless and average spiral galaxies. In order to investigate the existence of those galaxies we select a sample of galaxies with a negligible spheroidal component from Illustris TNG100 simulation. In a hierarchical formation scenario, where structures grow mainly via mergers, the existence of galaxies with a negligible bulge component (bulgeless) can be difficult to explain. Instituto de Astronomía Teórica y Experimental Despite some details we discuss, the resulting fit is good enough to ensure the overall framework can reproduce the observations. The tidal streams production is carried out through a ‘spray’ method and the definition of a tidal radius model. We produce theoretical stellar streams under different gravitational potentials, comparing the effects they generate on the ejected stars. Modelling the disruption of a satellite in its orbit around a host with an elementary-based particle halo was never done before. It was shown, in recent works, that it is a good, non-empirical model for the dark component of galaxies. This is done assuming the Milky Way’s dark halo is a self-gravitating system of fermions, which results from a maximum entropy production principle. In this work, we fit proper motion observables of the Sagittarius dwarf spheroidal stellar stream, the largest tidal debris of our Galaxy. The study of stellar streams allows us to constrain the mass distribution of galaxies. Sagittarius dSph stellar stream under a fermionic dark matter halo

Santiago Collazoįacultad de Ciencias Astronómicas y Geofísicas de La Plata In this contribution, I will showcase the galstreams library, an effort to collate the information in the literature for the nearly one hundred stellar streams known in the Milky Way, and use it to provide an ensemble view of the Galactic system of stellar streams’s properties, its current observational biases, and results inspired by recent discoveries made possible by the Gaia mission. Unearthing this record is essential to reconstructing the Galaxy’s accretion history, and modeling its dynamics is key to constrain the distribution of dark matter at the scales of the Galaxy and its satellites. A stellar stream is formed as stars are stripped from a dwarf galaxy or globular cluster by the Milky Way’s tidal forces, creating a fossil record of accretion that is best preserved in the halo, where streams are long lived. Stellar streams are to dynamics as stellar clusters are to stellar evolution: relatively “simple” systems of stars with a common origin whose common properties can be used to rewind evolutionary or dynamical processes much harder to disentangle in the Galactic field. Keeping track of the Galactic system of stellar streams

Redshift space distortions in illustris