Particle scattering by a test fluid on a Schwarzschild spacetime: the equation of state matters Donato Bini, Andrea Geralico and Sauro Succi Eur. Phys. J. C, 72 3 (2012) 1913 Published online: 07 March 2012 DOI: 10.1140/epjc/s10052-012-1913-5