Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Particle identification in ALICE : a Bayesian approach

Peer reviewe

5th International Conference on Operator Theory

The first of the annual Operator Theory conferences in Ti­ mi~oara held four years ago was a meeting of operator theory spe­ cialists from the National Institute for Scientific and Techni­ cal Creation in Bucharest and from the University of Timi~oara. Since then, the participation to these conferences has greatly increased, by being attended first by operator theorists from allover the country and (since 1978) by an increasing number of foreign mathematicians. Thus the 1980 Conference can be regarded as a truly international Operator Theory meeting, fifteen coun­ tries being represented at it. These conferences are conceived as a means to promote the cooperation between specialists in all areas of Operator Theory. Among the main topics in 1980 were: dilation theory, invariant subspaces, connections with the theory of cX-algebras, subnormal operators, multidimensional functional calculus etc. Though not included in this volume, we would like to mention that in 1980 some special sessions concerning other fields of Functional Ana­ lysis were organized at the Operator Theory conference. The research contracts of the Department of Mathematics of INCREST with the National Council for Sciences and Technoloa,y of Romania provided the means for developping the research activi­ ty in Functional Analysis; these contracts constitute the gene­ rous framework for these meetings