Calendar

The race towards the discovery and characterization of terrestrial extrasolar planets, possibly in the habitable zone of their host stars, that recent statistical analyses revealed to have high occurrence rates, represents a scientific adventure rich of great expectations, but also of great challenges. I will address the subject starting from my experience in planet hunting as a collaborator of the Italian ground-based surveys GAPS and APACHE, that aim for a similar goal in complementary ways: through the analysis of the stellar radial velocity variations the first, with the photometric transit method the second. In particular, I will explore the limits imposed by signals of stellar origin to the detection and mass determination of another Earth in precise radial velocity measurements, discussing some proposed strategies to mitigate the impact of stellar noise. Moreover, I will focus the discussion on M dwarfs, which represent a treasure trove for the search of Earth-like planets, but demand particular attention both for the detection and characterization of small planets.

Colliding neutron stars (NSs) are strong sources of gravitational radiation, and one of the most promising candidates for direct detection by advanced LIGO. Following the spectacular observations of gravitational waves from GW150914 – produced by the collision of two black holes – we can now expect that the direct detection of NS collisions is just around the corner. Growing observational evidence shows that NS collisions also produce bright electromagnetic signals: gamma-ray bursts, and macronovae. The former are brief flashes of gamma-ray radiation, the latter are short-lived infrared transients powered by the radioactive decay of heavy nuclei. The simultaneous detection of both electromagnetic and gravitational radiation arising from NS collisions would be a revolutionary observation. This exciting prospect makes these systems prime targets in the era of multi-messenger astronomy. In this talk, I present ongoing observational efforts to characterize the electromagnetic signatures of NS collisions, and outline future initiatives aimed at exploring the gravitational wave sky.