Context. Stellar kinematics in the external regions of globular clusters can be used to probe the validity of Newton's law in the low acceleration regimes without the complication of non-baryonic dark matter. Indeed, in contrast to the case of galaxies, in globular clusters a systematic deviation of the velocity dispersion profile from the expected

We examine the ability to test the black hole no-hair theorem at the 10% level in this decade using the binary black hole in OJ287. In the test we constrain the value of the dimensionless parameter q that relates the scaled quadrupole moment and spin of the primary black hole: q 2 = -q χ2. At the present we can say that q = 1 ± 0.3 (1σ), in

Recent evidence based independently on spectral line strengths and dynamical modelling point towards a non-universal stellar initial mass function (IMF), probably implying an excess of low-mass stars in elliptical galaxies with a high velocity dispersion. Here, we show that a time-independent bottom-heavy IMF is compatible neither with the observed

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The 1.5 m telescope GREGOR opens a new window to the understanding of solar small-scale magnetism. The first light instrumentation includes the Gregor Fabry Pérot Interferometer (GFPI), a filter spectro-polarimeter for the visible wavelength range, the GRating Infrared Spectro-polarimeter (GRIS) and the Broad-Band Imager (BBI). The excellent

The steep abundance gradient found by McCall, Shields, and Rybski (1981) in the Sbc galaxy NGC 3344 is confirmed by a measurement of the electron temperature in the outer H II region.