Gas inflows fueling AGN are now traceable at high-resolution with ALMA andNOEMA. Dynamical mechanisms are essential to exchange angular momentum anddrive the gas to the super-massive black hole. While at 100pc scale, the gas issometimes stalled in nuclear rings, recent observations reaching 10pc scale(50mas), inside the sphere of influence of the black hole, may bring smokinggun evidence of fueling, within a randomly oriented nuclear molecular disk. AGNfeedback is also observed, in the form of narrow and collimated molecularoutflows, which point towards the radio mode, or entrainment by a radio jet.Precession has been observed in a molecular outflow, indicating the precessionof the radio jet. One of the best candidates for precession is theBardeen-Petterson effect at small scale, which exerts a torque on the accretingmaterial, and produces an extended disk warp. The misalignment between the inner and large-scale disk, enhances thecoupling of the AGN feedback, since the jet sweeps a large part of themolecular disk.

Recent galaxy observations show that star formation activity changesdepending on galactic environments. In order to understand the diversity ofgalactic-scale star formation, it is crucial to understand the formation andevolution of giant molecular clouds in an extreme environment. We focus onobservational evidence that bars in strongly barred galaxies lack massive starseven though quantities of molecular gas are sufficient to form stars. In thispaper, we present a hydrodynamical simulation of a strongly barred galaxy,using a stellar potential which is taken from observational results of NGC1300,and we compare cloud properties between different galactic environments: bar,bar-end and spiral arms. We find that the mean of cloud's virial parameter is~1 and that there is no environmental dependence, indicating that thegravitationally-bound state of a cloud is not behind the observational evidenceof the lack of massive stars in strong bars. Instead, we focus on cloud-cloudcollisions, which have been proposed as a triggering mechanism for massive starformation. We find that the collision speed in the bar is faster than those inthe other regions. We examine the collision frequency using clouds' kinematicsand conclude that the fast collisions in the bar could originate fromrandom-like motion of clouds due to elliptical gas orbits shifted by the barpotential. These results suggest that the observed regions of lack of activestar-formation in the strong bar originate from the fast cloud-cloudcollisions, which are inefficient in forming massive stars, due to thegalactic-scale violent gas motion.

Roughly ten per cent of OB stars are kicked out of their natal clustersbefore ending their life as supernovae. These so called runaway stars cantravel hundreds of parsecs into the low-density interstellar medium, wheremomentum and energy from stellar feedback is efficiently deposited. In thiswork we explore how this mechanism affects large scale properties of thegalaxy, such as outflows. To do so we use a new model which treats OB stars andtheir associated feedback processes on a star-by-star basis. With this model wecompare two hydrodynamical simulations of Milky Way-like galaxies, one where weinclude runaways, and one where we ignore them. Including runaway stars leadsto twice as many supernovae explosions in regions with gas densities rangingfrom 1e-5 cm^-3 to 1e-3 cm^-3. This results in more efficient heating of theinter-arm regions, and drives strong galactic winds with mass loading factorsboosted by up to one order of magnitude. These outflows produce a more massiveand extended multi-phase circumgalactic medium, as well as a population ofdense clouds in the halo. Conversely, since less energy and momentum isreleased in the dense star forming regions, the cold phase of the interstellarmedium is less disturbed by feedback effects.

Satellites orbiting disc galaxies can induce phase space features such asspirality, vertical heating and phase-mixing in their discs. Such features havealso been observed in our own Galaxy, but the complexity of the Milky Way dischas only recently been fully mapped thanks to Gaia DR2 data. This complexbehaviour is mainly ascribed to repeated perturbations induced by theSagittarius dwarf galaxy (Sgr) along its orbit, pointing to this satellite asthe main dynamical architect of the Milky Way disc. Here, we model Gaia DR2observed colour-magnitude diagrams to obtain the first detailed star formationhistory of the ~ 2-kpc bubble around the Sun. It reveals three conspicuous andnarrow episodes of enhanced star formation that we can precisely date as havingoccurred 5.7, 1.9 and 1 Gyr ago. Interestingly, the timing of these episodescoincides with proposed Sgr pericentre passages according to i) orbitsimulations, ii) phase space features in the Galactic disc, and iii) Sgrstellar content. These findings most likely suggest that Sgr has also been animportant actor in the build-up of the Milky Way disc stellar mass, with itsperturbations repeatedly triggering major episodes of star formation.

In this paper we assess the correlation between recent observing runs (2018and 2019) and inclement weather, and demonstrate that these observing runs haveseen much more rainfall than would otherwise be expected, an increase of over200%. We further look at a number of observatory sites in areas that are facingor will face drought, and suggest that a strong environmental benefit wouldfollow from telescope allocation committees providing us an inordinate amountof telescope time at facilities located around the globe.