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Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched(More)
Recent observations of supernova remnants (SNRs) hint that they accelerate cosmic rays to energies close to ~10(15) electron volts. However, the nature of the particles that produce the emission remains ambiguous. We report observations of SNR W44 with the Fermi Large Area Telescope at energies between 2 x 10(8) electron volts and 3 x10(11) electron volts.(More)
The paucity of observed supermassive black hole binaries (SMBHBs) may imply that the gravitational wave background (GWB) from this population is anisotropic, rendering existing analyses suboptimal. We present the first constraints on the angular distribution of a nanohertz stochastic GWB from circular, inspiral-driven SMBHBs using the 2015 European Pulsar(More)
We present a new method of bias correction for deriving reliable Tully-Fisher distances in a magnitude or diameter selected sample of field galaxies. This normalized distance method (NDM) is first presented in a theoretical way using the formalism of bayesian statistics and is further applied to three different Tully-Fisher samples corresponding to three(More)
We present some preliminary results related to a project aimed at studying the evolution of the galaxy population in rich environments by means of the Color-Magnitude relation and of the Fundamental Plane. We derive the NIR and optical structural parameters for a sample of galaxies in the cluster AC118 at z=0.31. We prove that reliable structural parameters(More)
From new geometrical parallaxes of galactic Cepheids obtained with the Hipparcos satellite a new calibration of BVRI period-luminosity relations is deened independently of previous determinations. Using a compilation of extragalactic Cepheids new distances are derived for a sample of 17 nearby galaxies. It is shown that the PL relation is aaected by a(More)
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