RESUMO
The nearby radio galaxy M87 offers a unique opportunity to explore the connections between the central supermassive black hole and relativistic jets. Previous studies of the inner region of M87 revealed a wide opening angle for the jet originating near the black hole1-4. The Event Horizon Telescope resolved the central radio source and found an asymmetric ring structure consistent with expectations from general relativity5. With a baseline of 17 years of observations, there was a shift in the jet's transverse position, possibly arising from an 8- to 10-year quasi-periodicity3. However, the origin of this sideways shift remains unclear. Here we report an analysis of radio observations over 22 years that suggests a period of about 11 years for the variation in the position angle of the jet. We infer that we are seeing a spinning black hole that induces the Lense-Thirring precession of a misaligned accretion disk. Similar jet precession may commonly occur in other active galactic nuclei but has been challenging to detect owing to the small magnitude and long period of the variation.
RESUMO
The nearby radio galaxy M87 is a prime target for studying black hole accretion and jet formation1,2. Event Horizon Telescope observations of M87 in 2017, at a wavelength of 1.3 mm, revealed a ring-like structure, which was interpreted as gravitationally lensed emission around a central black hole3. Here we report images of M87 obtained in 2018, at a wavelength of 3.5 mm, showing that the compact radio core is spatially resolved. High-resolution imaging shows a ring-like structure of [Formula: see text] Schwarzschild radii in diameter, approximately 50% larger than that seen at 1.3 mm. The outer edge at 3.5 mm is also larger than that at 1.3 mm. This larger and thicker ring indicates a substantial contribution from the accretion flow with absorption effects, in addition to the gravitationally lensed ring-like emission. The images show that the edge-brightened jet connects to the accretion flow of the black hole. Close to the black hole, the emission profile of the jet-launching region is wider than the expected profile of a black-hole-driven jet, suggesting the possible presence of a wind associated with the accretion flow.
RESUMO
BACKGROUND: Home telemonitoring is a modern and effective disease management model that is able to improve medical care, quality of life, and prognosis of chronically ill patients, and to reduce expenditure. The objective of this study was to evaluate the efficacy, costs, and patients' and caregivers' acceptance of our model of telemedicine in a high-risk chronic heart failure (CHF) older population. METHODS: Patients with high risk/refractory CHF were included. In the case of alarm parameters' modifications, a cardiologist decided to inform the emergency department (ED), the patient's General Practioner, or to programme a clinical ambulatory control. RESULTS: Forty-eight CHF patients (28 males; 58.3%), with a mean age of 80.4 ± 7.7 years, entered this clinical experience. During the 20-months follow-up, four patients dropped out from counselling (8.3%), ambulatory clinical control within-24 h was planned in 18% of patients, 11% of patients were admitted to an ED, and 18% were hospitalized. Thirteen patients (29.5%) died a cardiac death; hospital admissions for heart failure decreased during the year after the enrolment when compared to the year before (from 35 to 12 acute HF hospitalizations/year; p = 0.0001). Moreover, in these HF patients followed, accesses to an ED for an acute episode of HF decompensation reduced from 21/year to five/year (p = 0.0001). The economic expenditure, calculated for the year before and after the enrolment, reduced from 116.856 Euros to 40.065 Euros/year. CONCLUSIONS: A telemedicine surveillance in high-risk older CHF patients determines a continuous and active contact between patients/caregivers, the Heart Failure Clinic, and family physicians, permitting an early evaluation of signs and symptoms of acute decompensation.
