Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare: Improved Orbital Parameters

Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole "no-hair theorem" at the 10% level

Stochastic Modeling of Multiwavelength Variability of the Classical BL Lac Object OJ287 on Timescales Ranging from Decades to Hours

We present the results of our power spectral density analysis for the BL Lac object OJ 287, utilizing the Fermi-LAT survey at high-energy.-rays, Swift-XRT in X-rays, several ground-based telescopes and the Kepler satellite in the optical, and radio telescopes at GHz frequencies. The light curves are modeled in terms of continuous-time autoregressive moving average (CARMA) processes. Owing to the inclusion of the Kepler data, we were able to construct for the first time the optical variability power spectrum of a blazar without any gaps across similar to 6 dex in temporal frequencies. Our analysis reveals that the radio power spectra are of a colored-noise type on timescales ranging from tens of years down to months, with no evidence for breaks or other spectral features. The overall optical power spectrum is also consistent with a colored noise on the variability timescales ranging from 117 years down to hours, with no hints of any quasi-periodic oscillations. The X-ray power spectrum resembles the radio and optical power spectra on the analogous timescales ranging from tens of years down to months. Finally, the.-ray power spectrum is noticeably different from the radio, optical, and X-ray power spectra of the source: we have detected a characteristic relaxation timescale in the Fermi-LAT data, corresponding to similar to 150 days, such that on timescales longer than this, the power spectrum is consistent with uncorrelated (white) noise, while on shorter variability timescales there is correlated (colored) noise

Pilot study on reflectance confocal microscopy imaging of lichen planus: a real-time, non-invasive aid for clinical diagnosis

Background Lichen planus (LP) represents a relatively common skin inflammatory entity included in the major group of interface dermatitis. In recent years, reflectance confocal microscopy has demonstrated to be a valuable tool for the in vivo characterization of various skin diseases with cellular level resolution. No data are currently available that uses reflectance confocal microscopy to study LP. Observations In this study, we have investigated the clinical and confocal features of five cases of histopathologically proven LP, and we have correlated the observed features with histopathological findings. The most characteristic criterion was the presence of interface dermatitis. Papillary rims, usually visible in normal skin, were obscured by the presence of a diffuse inflammatory cells infiltrate, arranged in sheet-like structures that surrounded the junction almost completely. There was an almost total obliteration of the ring-like structures around DP, which appeared non-edged and non-rimmed. Granular cells appeared as very large, polygonal structures, with an evident grainy cytoplasm, with the transition between spinous and granular cells being clearly recognizable, and this feature corresponded to hypergranulosis in histology. The presence of inflammatory cells at the level of the epidermis was seen as round-to-polygonal bright structures in the context of a variable degree of epidermal disarray and spongiosis. Melanophages in dermis were visible as brightly refractile, plump, oval to stellate-shaped cells. Prominent round or linear dark canalicular structures corresponded to dilated blood vessels in the superficial dermis on histopathology and appeared horizontally oriented in confocal sections. Conclusions Reflectance confocal microscopy may represent a real-time, non-invasive aid to clinical diagnosis of LP. However, it might be difficult to distinguish between different subtypes of interface dermatitis. Further research, including larger case series, will better define a possible differential diagnosis of these diseases using confocal microscopy