Timing studies of compact objects

by Dr Claudio Germana' (Dip. di Astronomia, Univ. di Padova)

Friday 11 Mar 2011, 15:00 → 16:00 Europe/Rome

Aula Wick (Dip. di Fisica - Edificio G. Marconi)

The detailed knowledge of the temporal behaviour of astrophysical objects is one of the main sources of information about physical processes occurring in several classes of objects. Fast photon counters for studying rapid phenomena in the X-ray band have revealed millisecond time-scale modulations in the X-ray range from Low Mass X-ray Binaries. This time scale is typical for matter orbiting close to the compact object. Therefore, timing studies of these sources could provide a way to investigate the motion of matter in a strongly curved space-time, thus probing General Relativity in strong field limit. We observed the Crab pulsar at the 1.82 m telescope in Asiago with the optical photon-counter Aqueye (few hundreds of picoseconds time resolution). We measured the rotational period of the neutron star with accuracy up to some picosecond and the spindown rate of the rotational period. From the theoretical point of view we ran simulations of a numerical code describing the signal emitted by a clump of free particles orbiting a Schwarzschild black hole.