Volume 2 Issue 2, February 2018

Recent observations of extreme variability in active galactic nuclei have pushed standard viscous accretion disk models over the edge. I suggest either that some kind of non-local physics dominates accretion disks, or that the optical output we see comes entirely from reprocessing a central source.

The Ali Cosmic Microwave Background Polarization Telescope — currently under construction in the Ngari prefecture of Tibet — will search for primordial gravitational waves and probe the origin of the Universe.

Observations and thermal models of the first interstellar visitor 1I/‘Oumuamua show that ices could have survived a long interstellar journey, suggesting the possibility that ‘Oumuamua could be a comet.

New spacecraft measurements show that the dust cycle plays a key role in driving upward transport of water vapour in the atmosphere of Mars and, consequently, Martian water loss to space.

Newly measured proper motions of a dozen stars in the Sculptor dwarf galaxy provide important insight into its distribution of dark matter. This result was made possible by combining measurements of star positions from Hubble Space Telescope and Gaia data.

The East Asia Very Long Baseline Interferometry Network (EAVN) consists of 21 radio telescopes whose equipment and frequency setup allow fine imaging of jets in active galaxies, high-accuracy astrometry of masers and pulsars, and spacecraft positioning.

Mars Climate Sounder’s multi-annual observations of the vertical distribution of water and dust in the Martian atmosphere show that deep convection from dust storms transports water from the lower to the middle atmosphere, enhancing water loss to space.

Visible and near-infrared spectra of the interstellar object ‘Oumuamua indicate the presence of inhomogeneities in surface composition, which are dominated by organic-rich material after long-term exposure to cosmic rays. An ice-rich interior is not ruled out.

Similar physical processes regulate the angular momentum of gas-giant planets and planetary-mass brown dwarfs. These processes are active mostly during the early phase of planetary evolution as rotation rates do not change after the first 2–300 Myr.

Methanol maser lines are key tracers of the magnetic field strength in high-mass star-forming regions. Here the authors model the magnetic properties of methanol in detail, including the hyperfine structure arising from its internal rotation.

A novel unsupervised autoencoding recurrent neural network produces state-of-the-art supervised classification models. This network can continue to learn from new unlabelled observations and may be used in other unsupervised tasks.

Precise proper motions of Sculptor’s stars based on Gaia and the Hubble Space Telescope show that Sculptor moves on a high-inclination elongated orbit around the Milky Way and require abandoning conventional models for Sculptor’s mass distribution.

An M = −14 r-band magnitude cutoff for satellite galaxies around isolated massive early-type galaxies indicates that the luminosity function of these satellite galaxies is largely determined by their interaction with their host’s environment.

During reconfinement in unmagnetized relativistic jets, a centrifugal instability develops that leads to a turbulent state. This instability likely lies behind the division of active galactic nuclei jets into the two Fanaroff–Riley classes.

The MICROSCOPE experiment has set the best upper bound to date on the weak equivalence principle, proving Einstein’s postulate with an unprecedented precision, as explained by Principal Investigator Pierre Touboul and team members Manuel Rodrigues and Joel Bergé.