Articles

Rotation of the Galactic bar at the centre of the Milky Way can explain gaps and asymmetries in stellar stream Palomar 5. Similar streams close to the Galactic Centre are therefore unfit for probing the dark matter subhalo interactions in our Galaxy.

A previously unidentified class of variable stars has been found in OGLE survey data, characterized by periodic brightness variations on ~30-min timescales, amplitudes of ~0.3 mag and temperatures of ~30,000 K. They are potentially evolved low-mass stars.

Ultrarelativistic photons and neutrinos from gamma-ray bursts offer a testbed for quantum gravity effects that would lead to an energy dependence of the travel times. A statistical analysis of astrophysical data shows that this behaviour may have been observed.

The origin of Galactic positrons that produce gamma ray emission when annihilated is still debated. Mergers of two white dwarfs are likely to be the main source of these positrons. Such mergers produce sub-luminous, thermonuclear supernovae.

Using an innovative method, the mass of a pulsar can be constrained using the maximum ‘glitch’ in the star’s rotational frequency: the bigger the glitch, the lower the mass. This method is used to estimate the mass of all observed glitchers.

Liquid methane lakes dot Titan’s polar regions. Numerical models reveal that the creation of buoyant bubbles through nitrogen exsolution near the bed of the Ligeia Mare lake can explain transient brightenings observed by Cassini on the lake’s surface.

The stacking of nearly three-quarters of a million spectra has unearthed a previously unknown component of the Galactic halo: a widely distributed, neutral, excited hydrogen layer that could harbour a sizeable proportion of the Milky Way’s baryons.

Periodic pulsations of polarized emission and a strong magnetic field were found in a white-dwarf double system. These findings confirm a pulsar-like emission mechanism for the system that has so far been associated only with neutron stars.