Abstract: The region around the Galactic Center contains a well-characterized excess of gamma rays, which has garnered great interest as a possible signal of either dark matter particles colliding and annihilating, or a previously undiscovered population of pulsars in the stellar bulge. Analyses of the photon statistics of this excess have been used to argue that the pulsar interpretation is strongly favored -- however, I will present recent work arguing that it may be premature to exclude a dark matter origin for the excess on these grounds. I will outline the history of our understanding of the excess and the arguments for various interpretations, describe the current status of the controversy, and discuss future paths forward.
What sets the composition of nascent planets is a fundamental question in astronomy, and one that is extremely timely considering the large number of exoplanets with very different characteristics that have been discovered in the past years. Whether these planets can host life depends directly on the composition and distribution of the gas where they form, i.e. protoplanetary disks. Thanks to ALMA we can now image the emission of key organic species at scales of ~15 au.
In this talk I will show recent ALMA observations of HCN, one of the simplest but bright N-bearing species in disks, and of its two isotopologues. HCN is of particular interest as it is thought to be the starting point for the formation of the precursors of RNA and proteins. Moreover, the N isotopic ratio 14N/15N is often used to determine the origin of the material in our solar system. However, the 14N/15N ratios varies dramatically between different solar system bodies, and the cause of this variation remains a mystery. I will then comment on the most complex N-bearing species detected in disks so far, and conclude by discussing our current efforts to constrain the chemical structure of disks in the planet and comet forming zone.