Observation of Gravitational Waves from a Binary Black Hole Merger

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160)  Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

Stabilized high-power laser system for the gravitational wave detector advanced LIGO

An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments.

Directional limits on persistent gravitational waves using LIGO S5 science data

The gravitational-wave (GW) sky may include nearby pointlike sources as well as stochastic backgrounds. We perform two directional searches for persistent GWs using data from the LIGO S5 science run: one optimized for pointlike sources and one for arbitrary extended sources. Finding no evidence to support the detection of GWs, we present 90% confidence level (C.L.) upper-limit maps of GW strain power with typical values between 2-20×10(-50)  strain(2) Hz(-1) and 5-35×10(-49)  strain(2) Hz(-1) sr(-1) for pointlike and extended sources, respectively. The latter result is the first of its kind. We also set 90% C.L. limits on the narrow-band root-mean-square GW strain from interesting targets including Sco X-1, SN 1987A and the Galactic center as low as ≈7×10(-25) in the most sensitive frequency range near 160 Hz.

[A case report of pharyngeal diphtheria]

Report about a case of toxic diphtheria in a 25-years-old woman. In consideration of new findings about the serum antibody level to diphtheria toxin in the population of the GDR the speciality in this case is described. The risk of possibility on more diseases is demonstrated. In result of all findings will it be necessary, that the disease of diphtheria must be recapitulated. It must bear in mind, that such severe cases can be avoided by systematic revaccination even of adults.

[Experiences in the use of the so-called M-mode method in the clinical diagnosis of heart diseases]

Since formerly only the diastolic phase of the curve of the mitral valve was in the centre of interest for diagnosing the mitral stenosis, nowadays the systolic area is more taken into consideration, the changes of which apart from the hypertrophies of the heart walls increasingly gains significance for the diagnostics of the idiopathic hypertrophic cardiomyopathies, the floppy valve syndrome, the aneurysm of the heart wall, the atrial septum defect as well as for systolic murmurs of different genesis. The registration of the movement of the posterior wall and the septum give the possibility of determination of the volume. Thus mean values of the stroke volume, the minute volume of the heart and the cardiac index showed a conspicuously good correspondence in persons with healthy heart compared with former determinations by dye dilution technique. As formerly (dye examinations) we found significant differences between normals and values of patients with mitral stenosis in stroke volume, ejection fraction, cardiac output and cardiac index, when we used the echocardiographic technique.

[Changes in the munber of 60-year old and older internal patients during a period of 10 years]

In 273 persons, of them 76 with ischaemic heart disease, 46 with non-coronary heart diseases (vitia, hypertension, chronic cor pulmonale, cardiomyopathy) and a control group of 115 healthy persons, during and after submaximal load under bicycle ergometry the ECG after work was recorded, in which case indication and contraindications of the WHO were taken into consideration. Especially investigated were the degree and the morphology of the ST-T-changes in differential-diagnostic respect in ischaemic heart disease and functional disturbances of the repolarisation. Apart from this the disturbances of rhythm and conduction system were analysed, which appeared under stress. The highest diagnostic evidence was under a load of 400-600 kmp/min and a pulse rate of 130-150/mim.