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 M ⊙ . 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 NGC 4993 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.

Recent work has linked the quiescent luminosities and hard/soft spectral state switches of neutron stars (NSs) to their spinning magnetic fields. It is shown here that the quiescent luminosities and spectral state switches of galactic black hole candidates (BHCs) could be produced in the same way for spin rates below 100 Hz and magnetic fields above 10 10 G. It is also shown that the ultrasoft peaks and large flickering amplitudes of the BHCs would be expected from the surfaces of massive NSs. None of the few spectral characteristics that distinguish BHCs from low mass NSs have been explained in terms of event horizons. Serious consideration of the possibility that they might simply be massive NSs opens an avenue for proof of event horizons by negation, but requires the use of a space-time metric that has no event horizon. The Yilmaz exponential metric used here is shown to have an innermost marginally stable orbit with radius, binding energy and Keplerian frequency that are within a few percent of the same quantities for the Schwarzschild metric. A maximum NS mass of ∼ 10M ⊙ is found for the Yilmaz metric. The two metrics essentially differ only by the presence/absence of a surface for the BHCs, thus enabling proof or disproof of the existence of event horizons.

Recent brightness fluctuation and auto-correlation analysis of time series data, and micro-lensing size scales, seen in Q0957+561 A,B, have produced important information about the existence and characteristic physical dimensions of a new non-standard magnetically dominated internal structure contained within this quasar. This new internal quasar structure, which we shall call the Schild-Vakulik Structure, can be consistently explained in terms of a new class of gravitationally collapsing solutions to the Einstein field equations which describe highly red shifted, Eddington limited, Magnetospheric, Eternally Collapsing Objects (MECO) that contain intrinsic magnetic moments. Since observations of the Schild-Vakulik structure within Q0957+561 imply that this quasar contains an observable intrinsic magnetic moment, this represents strong evidence that the quasar does not have an event horizon.