Volume 3 Issue 3, March 2019

Both NASA and ESA hope their next Mars rovers will find evidence that life once thrived on Mars, but they have different strategies to reach this goal. Their landing site choices reflect this difference.

The existence of Earth’s Trojan asteroids is not well constrained and represents a major gap in our inventory of small bodies in near-Earth space. Their discovery would be of high scientific and human interest.

The degree of polarization of gamma-ray bursts seems to be lower than previously thought. Gamma-ray polarimetry can reveal the emission mechanism and physical information inside the relativistic jet.

The winds from growing supermassive black holes appear to be located tens of parsecs from the centres of their host galaxies. This location fits with the idea that these outflows influence the progression of star formation.

The sunspot number time series is an essential tool to determine the secular variations of solar activity, but particular care must be taken to handle and present incomplete temporal coverage. The authors present the current state of research and propose a new way to visualize long-term solar activity data.

A review of the various techniques to obtain photometric redshifts, from template-fitting to machine learning and hybrid schemes, and a description of the latest results on extragalactic samples and how survey strategy choices impact redshift accuracy.

A spatially ubiquitous energy flux from the interior of the Sun reaches the corona through Alfvénic waves generated by internal acoustic modes. Such flux persists for the whole solar cycle and contributes significantly to the energy in the corona.

ALMA observations of well-studied quadruple stellar system HD 98800 have revealed the presence of a circumbinary disk in a polar orientation around one of the binary pairs, providing observational confirmation of the theoretical stability of such an arrangement.

Using SN 1987A as a cosmic laboratory, Miceli et al. have measured the shock acceleration of ions heavier than oxygen, finding that the post-shock temperature of a wide range of ions is mass dependent.

Increased UV–optical nuclear emission in a nearby galaxy together with a spectrum showing emission lines typical of unobscured AGNs and Bowen fluorescence features suggests a longer-term event of intensified accretion onto the central supermassive black hole.

New variability data of the accretion disk in active galactic nuclei argue for the existence of a farther away under-appreciated non-disk component associated with high-density photoionized material that is uplifted from the outer accretion disk.

Precise polarization measurements from the gamma-ray burst polarimeter POLAR suggest that the gamma-ray emission is at most polarized at a level lower than predicted by some models and also shows intrapulse evolution of its polarization angle.

The distance of outflowing gas from the galaxy centre for 915 quasars is found to be typically tens of parsecs. Typical outflow mass rates and energies indicate that these outflows are energetic enough to influence the evolution of their host galaxies.

The concordance cosmology model is poorly tested at high redshifts. Here the expansion rate of the Universe in the range 0.5 < z < 5.1 is measured based on a Hubble diagram of quasars, whose distances are estimated from their X-ray and ultraviolet emission.