Gravitational waves from coalescing massive black holes in young dense clusters

HST observations reveal that young massive star clusters form in gas-rich environments like the Antenn{\ae} galaxy which will merge in collisional processes to form larger structures. These clusters amalgamate and if some of these clusters harbour a massive black hole in their centres, they can become a strong source of gravitational waves when they coalesce. In order to understand the dynamical processes that are into play in such a scenario, one has to carefully study the evolution of the merger of two of such young massive star clusters and more specifically their respective massive black holes. This will be a promising source of gravitational waves for both, LISA and the proposed Big Bang Observer (BBO), whose first purpose is to search for an inflation-generated gravitational waves background in the frequency range of $10^{-1}-1$ Hz. We used high-resolution direct summation $N-$body simulations to study the orbital evolution of two colliding globular clusters with different initial conditions. Even if the final eccentricity is almost negligible when entering the bandwidth, it will suffice to provide us with detailed information about these astrophysical events.Comment: Based on contribution at the Sixth International LISA Symposium, 7 page

Miguel de Unamuno and Heraclitus: from ‘The Eternal Elegy’ (‘La elegía eterna’) to ‘The Cut Flower’(‘La flor tronchada’)

Podeu consultar la versió en castellà del document a: http://hdl.handle.net/2445/33131The aim of this brief article is to demonstrate and analyze the influence of Heraclitus’s thought on some of the poems written by Miguel de Unamuno, in particular ‘La elegía eterna’ and ‘La flor tronchada’. At times –as in ‘La elegía eterna’– Heraclitus merely serves as a sort of a walking stick, an aid to his efforts to poetically reveal his anxieties. On other occasions –as in ‘La flor tronchada’– he genuinely needs Heraclitus’s philosophy to illustrate his view of human life and its relation to God as unending warfare