12 research outputs found

    A Universal Power-law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows

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    We present a framework for characterizing the spatiotemporal power spectrum of the variability expected from the horizon-scale emission structure around supermassive black holes, and we apply this framework to a library of general relativistic magnetohydrodynamic (GRMHD) simulations and associated general relativistic ray-traced images relevant for Event Horizon Telescope (EHT) observations of Sgr A*. We find that the variability power spectrum is generically a red-noise process in both the temporal and spatial dimensions, with the peak in power occurring on the longest timescales and largest spatial scales. When both the time-averaged source structure and the spatially integrated light-curve variability are removed, the residual power spectrum exhibits a universal broken power-law behavior. On small spatial frequencies, the residual power spectrum rises as the square of the spatial frequency and is proportional to the variance in the centroid of emission. Beyond some peak in variability power, the residual power spectrum falls as that of the time-averaged source structure, which is similar across simulations; this behavior can be naturally explained if the variability arises from a multiplicative random field that has a steeper high-frequency power-law index than that of the time-averaged source structure. We briefly explore the ability of power spectral variability studies to constrain physical parameters relevant for the GRMHD simulations, which can be scaled to provide predictions for black holes in a range of systems in the optically thin regime. We present specific expectations for the behavior of the M87* and Sgr A* accretion flows as observed by the EHT

    Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign

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    Abstract: In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M ⊙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded

    Effectiveness of Saccharomyces Boulardii CNCM I-745 probiotic in acute inflammatory viral diarrhoea in adults: results from a single-centre randomized trial

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    Abstract Background Probiotics are effective for treating acute infectious diarrhoea caused by bacteria, but there are inconsistent results for the effectiveness of probiotics for diarrhoea caused by viruses. In this article we want to determine whether Sb supplementation has an effect on acute inflammatory viral diarrhoea diagnosed with the multiplex panel PCR test. The aim of this study was to evaluate the efficacy of Saccharomyces boulardii (Sb) as a treatment in patients diagnosed with viral acute diarrhoea. Methods From February 2021 to December 2021, 46 patients with a confirmed diagnosis of viral acute diarrhoea diagnosed with the polymerase chain reaction multiplex assay were enrolled in a double-blind, randomized placebo-controlled trial. Patients received paracetamol 500 mg as a standard analgesic and 200 mg of Trimebutine as an antispasmodic treatment plus 600 mg of Sb (n = 23, 1 × 109/100 mL Colony forming unit) or a placebo (n = 23) orally once daily for eight days. The improvement in and severity of symptoms were measured using a symptom diary, the Patient Global Impression and the Patient Global Impression of Change scales (days 4 and 8), both answered and recorded by the patient. Results Of the 46 patients who completed treatment, 24 (52%) were men and 22 (48%) were women. The average age was 35.6 ± 12.28 years (range 18 to 61 years). The average duration of the evolution of illness at the time of diagnosis was 0.85 ± 0.73 days (maximum 2 days). On day 4 after the diagnosis, 20% reported pain and 2% reported fever, but on day 8, no patient reported pain or fever. On day 4, 70% of patients in the Sb group and 26% in the placebo group reported improvement (P = 0.03), based on the Patients’ Global Impression of Change scale, which assesses patient’s rating of overall improvement. These findings suggest that 3 to 4 days of treatment with Sb helped to improve symptoms of diarrhoea caused by a virus. Conclusion Treatment with Sb on acute inflammatory diarrhoea of viral aetiology shows no changes regarding the severity of the symptoms; nevertheless, it seems to impact improvement positively. Trial registration 22CEI00320171130 dated on 16/12/2020, NCT05226052 dated on 07/02/2022

    Event Horizon Telescope observations of the jet launching and collimation in Centaurus A

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    Very-long-baseline interferometry (VLBI) observations of active galactic nuclei at millimetre wavelengths have the power to reveal the launching and initial collimation region of extragalactic radio jets, down to 10–100 gravitational radii (rg ≡ GM/c2) scales in nearby sources1. Centaurus A is the closest radio-loud source to Earth2. It bridges the gap in mass and accretion rate between the supermassive black holes (SMBHs) in Messier 87 and our Galactic Centre. A large southern declination of −43\ub0 has, however, prevented VLBI imaging of Centaurus A below a wavelength of 1 cm thus far. Here we show the millimetre VLBI image of the source, which we obtained with the Event Horizon Telescope at 228 GHz. Compared with previous observations3, we image the jet of Centaurus A at a tenfold higher frequency and sixteen times sharper resolution and thereby probe sub-lightday structures. We reveal a highly collimated, asymmetrically edge-brightened jet as well as the fainter counterjet. We find that the source structure of Centaurus A resembles the jet in Messier 87 on ~500 rg scales remarkably well. Furthermore, we identify the location of Centaurus A’s SMBH with respect to its resolved jet core at a wavelength of 1.3 mm and conclude that the source’s event horizon shadow4 should be visible at terahertz frequencies. This location further supports the universal scale invariance of black holes over a wide range of masses5,6

    Observation of Overlapping Spin-1 and Spin-3 (D)over-bar(0)K(-) Resonances at Mass 2.86 GeV/c(2)

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    The resonant substructure of B-s(0) -> (D) over bar K-0(-)pi(+) decays is studied using a data sample corresponding to an integrated luminosity of 3.0 fb(-1) of pp collision data recorded by the LHCb detector. An excess at m((D) over bar K-0(-)) approximate to 2.86 GeV/c(2) is found to be an admixture of spin-1 and spin-3 resonances. Therefore, the D-sJ*(2860)(-) state previously observed in inclusive e(+)e(-) -> (D) over bar (K-X)-K-0 and pp -> (D) over bar (K-X)-K-0 processes consists of at least two particles. This is the first observation of a heavy flavored spin-3 resonance, and the first time that any spin-3 particle has been seen to be produced in B decays. The masses and widths of the new states and of the D-s2*(2573)(-) meson are measured, giving the most precise determinations to date

    C. Literaturwissenschaft.

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    Open charm production and asymmetry in ppNe collisions at sNN=\sqrt{s_{\scriptscriptstyle\rm NN}} = 68.5 GeV

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    A measurement of D0D^0 meson production by the LHCb experiment in its fixed-target configuration is presented. The production of D0D^0 mesons is studied with a beam of 2.5 TeV protons colliding on a gaseous neon target at rest, corresponding to a nucleon-nucleon centre-of-mass energy of sNN\sqrt{s_{\rm NN}} = 68.5 GeV. The D0D^0 and D0{\overline D^0} production cross-section in ppNe collisions in the centre-of-mass rapidity range y[2.29,0]y^{\star}\in [-2.29, 0] is found to be σD0y[2.29,0]=48.2±0.3±4.5μb/nucleon\sigma_{D^{0}}^{y^\star \in [-2.29, 0]} = 48.2 \pm 0.3 \pm 4.5 \,\mu\textrm{b/nucleon} where the first uncertainty is statistical and the second is systematic. The D0D0D^0-{\overline D^0} production asymmetry is also evaluated and suggests a negative trend at large negative yy^{\star}. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1%\% intrinsic charm and 10%\% recombination contributions better describe the data than the other models consideredA measurement of D0{{D}} ^0 meson production by the LHCb experiment in its fixed-target configuration is presented. The production of D0{{D}} ^0 mesons is studied with a beam of 2.5 TeV\,\text {Te\hspace{-1.00006pt}V} protons colliding on a gaseous neon target at rest, corresponding to a nucleon–nucleon centre-of-mass energy of sNN=68.5GeV\sqrt{s_{\scriptscriptstyle \text {NN}}} = 68.5\,\,\text {Ge\hspace{-1.00006pt}V} . The sum of the D0{{D}} ^0 and D0{\hspace{0.0pt}\overline{\hspace{0.0pt}{D}}} {}^0 production cross-section in pNep\text {Ne} collisions in the centre-of-mass rapidity range y[2.29,0]y^{\star }\in [-2.29, 0] is found to be \sigma _{D^{0}}^{y^\star \in [-2.29, 0]} = 48.2 \pm 0.3 \pm 4.5 \,\upmu \text {b}/\text {nucleon} where the first uncertainty is statistical and the second is systematic. The D0D0{{{D}} ^0}-{{\hspace{0.0pt}\overline{\hspace{0.0pt}{D}}} {}^0} production asymmetry is also evaluated and suggests a trend towards negative values at large negative yy^{\star }. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1%\% intrinsic charm and 10%\% recombination contributions better describe the data than the other models considered.A measurement of D0D^0 meson production by the LHCb experiment in its fixed-target configuration is presented. The production of D0D^0 mesons is studied with a beam of 2.5 TeV protons colliding on a gaseous neon target at rest, corresponding to a nucleon-nucleon centre-of-mass energy of sNN\sqrt{s_{\rm NN}} = 68.5 GeV. The sum of the D0D^0 and D0{\overline D^0} production cross-section in ppNe collisions in the centre-of-mass rapidity range y[2.29,0]y^{\star}\in [-2.29, 0] is found to be σD0y[2.29,0]=48.2±0.3±4.5μb/nucleon\sigma_{D^{0}}^{y^\star \in [-2.29, 0]} = 48.2 \pm 0.3 \pm 4.5 \,\mu\textrm{b/nucleon} where the first uncertainty is statistical and the second is systematic. The D0D0D^0-{\overline D^0} production asymmetry is also evaluated and suggests a trend towards negative values at large negative yy^{\star}. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1%\% intrinsic charm and 10%\% recombination contributions better describe the data than the other models considered

    Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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    Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

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