Abstract
In this paper we present the most recent observations of gravitational waves (GWs) by LIGO and Virgo detectors. We also discuss contributions of the recent Nobel prize winner, Sir Roger Penrose to understanding gravitational radiation and black holes (BHs). We make a short introduction to GW phenomenon in general relativity (GR) and we present main sources of detectable GW signals. We describe the laser interferometric detectors that made the first observations of GWs. We briefly discuss the first direct detection of GW signal that originated from a merger of two BHs and the first detection of GW signal form merger of two neutron stars (NSs). Finally we present in more detail the observations of GW signals made during the first half of the most recent observing run of the LIGO and Virgo projects. Finally we present prospects for future GW observations.
Highlights
The first terrestrial direct detection of gravitational waves (GWs) on 14 September 2015, was a milestone discovery, and it opened up an entirely new window to explore the universe
According to general relativity (GR), gravitational attraction is a consequence of the curvature in space-time and GWs are the ripples on the fabric of space-time that travel at the speed of light generated by the accelerating masses
Before presenting the properties of the GW signals registered during the O3a run we summarize definitions of the parameters that determine the evolution of the binary systems
Summary
The first terrestrial direct detection of GWs on 14 September 2015, was a milestone discovery, and it opened up an entirely new window to explore the universe. It implies that the metric perturbation represents a GW that propagates at the speed of light [1]. The peak GW strain during the first detection event was as small as 10−21 It isn’t easy to detect the GWs, and it took elaborate efforts over many decades to devise an experimental setup sensitive enough to observe weak GW signals directly. In Section we present main GW measurements in the first two observational runs of the LIGO and Virgo detectors.
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