Seminars and Colloquia at ESO Garching and on the campus

The interplay between the interstellar medium (ISM), star formation, and stellar feedback is a key driver of galaxy evolution across cosmic time. Exactly how this happens, and whether this cycle changes depending on the galactic environment, is still highly debated. Nearby galaxies (<10Mpc) offer the perfect laboratory, where current facilities such as ALMA, JWST and HST reach cloud-scale (<100pc) resolution, thus serving as a bridge between detailed studies in our own Galaxy and integrated measurements from more distant objects.

I will first present our work on studying the resolved properties of the ISM using an innovative extinction imaging technique, which exploits space-based optical data to map the dust (and gas) content of nearby disc galaxies at 0.1” resolution (~5pc). Our study of M51 using this technique has shown that there are clear changes in the properties of the ISM depending on the galactic environment, as well as on the type of spiral potential felt by the gas, which were missed by previous cloud studies of this galaxy.

On the other hand, stellar feedback has been highlighted to be a major contributor to the observed inefficiency of star formation at cloud-scales. JWST now allows us to unveil the still emerging young star clusters (YSCs) within the dusty clouds, which are still actively driving stellar feedback. I will showcase our pilot NIRSpec/MOS survey of emerging YSCs in NGC628, as part of the Feedback in Emerging extrAgalactic Star clusTers (FEAST) project. Spectroscopy in the 1-5 micron range highlights the chemical complexity of these star-forming regions, simultaneously probing the HII regions and photodissocation regions (PDRs). As YSCs age, they become less embedded, with a fainter, less compact PDR. I will show how the radiation field is affecting the polycyclic aromatic hydrocarbon emission associated with these emerging YSCs.

The supermassive black holes (SMBHs) that live in galactic centers power a variety of high energy astrophysical sources, from active galactic nuclei to SMBH binary mergers.  Advances in time domain astronomy have led to renewed interest in SMBH transients of dynamical origin, such as tidal disruption events (TDEs), quasi-periodic eruptions, and LISA-band extreme mass ratio inspirals (EMRIs).  I will first discuss the common "loss cone" mechanisms that excite stellar mass objects onto the high-eccentricity orbits needed to produce these types of electromagnetic and gravitational wave transients, with an emphasis on the remaining uncertainties that complicate estimates for rates and observability.  Next, I will describe recent observational and theoretical advances that have opened the door to using TDEs for SMBH parameter estimation.  Finally, I will make some predictions for the populations of EMRIs visible to the future LISA mission, including recent results suggesting that present-day TDE surveys may be much more viable predictors of EMRI dynamics than was previously believed.