First Sagittarius A* Event Horizon Telescope Results. VII. Polarization of the Ring

The Event Horizon Telescope observed the horizon-scale synchrotron emission region around the Galactic center supermassive black hole, Sagittarius A* (Sgr A*), in 2017. These observations revealed a bright, thick ring morphology with a diameter of 51.8 ± 2.3 μas and modest azimuthal brightness asymmetry, consistent with the expected appearance of a black hole with mass M ≈ 4 × 106 M ⊙. From these observations, we present the first resolved linear and circular polarimetric images of Sgr A*. The linear polarization images demonstrate that the emission ring is highly polarized, exhibiting a prominent spiral electric vector polarization angle pattern with a peak fractional polarization of ∼40% in the western portion of the ring. The circular polarization images feature a modestly (∼5%–10%) polarized dipole structure along the emission ring, with negative circular polarization in the western region and positive circular polarization in the eastern region, although our methods exhibit stronger disagreement than for linear polarization. We analyze the data using multiple independent imaging and modeling methods, each of which is validated using a standardized suite of synthetic data sets. While the detailed spatial distribution of the linear polarization along the ring remains uncertain owing to the intrinsic variability of the source, the spiraling polarization structure is robust to methodological choices. The degree and orientation of the linear polarization provide stringent constraints for the black hole and its surrounding magnetic fields, which we discuss in an accompanying publication

Teaching Painting: How Can Painting be Taught in Art Schools

The ways in which painting is taught within art schools and academies have undergone several significant changes in recent years. As the barriers between media have eroded into more fluid borders, art schools have responded by adapting and evolving. Many painting departments have been absorbed into general fine art courses, but the development of specialist painting courses and pathways still continues. How have these courses defined and redefined themselves to reflect the current artistic landscape, and how can painting maintain an identity within nonspecialist approaches? This book includes contributions by Maggie Ayliffe and Christian Mieves, senior lecturers at Wolverhampton School of Art, who write about their Dirty Practice workshop that introduces risk and open-ended approaches to painting; Ian Gonczarow, who discusses how painting can be approached and taught in a post-analogue world; and Sarah Horton and Sarah Longworth-West, who detail their series of workshops that encourage a quick rotation through different, overlapping approaches to producing work