New trick uses velocity maps to measure weak lensing directly

Despite dark matter dominating the Universe with 84% of the mass compared to 16% of baryonic matter, it is non-interacting and cannot be measured directly. There are techniques to measure the fraction of  the two types of matter but weak gravitational lensing is the...

Dark matter halo of dwarf galaxies shaped by supernova feedback

The Cold Dark Matter (CDM) model has proven very successful, however there exists a long standing problem of ubiquitous ‘cusps’ of dark matter halos, i.e. the dark matter distribution sharply increases to a high value at a central point. Significant...

Infant mortality in space

CAASTRO PhD student Joe Callingham (University of Sydney) has re-examined a ‘boring’ radio source and shown it could hold the key to a long-standing problem in astronomy: why there seem to be more ‘baby’ radio galaxies than mature ‘giant’ ones. The source is called...

Slow rotating galaxies join clusters late and migrate to centre

Previous surveys have shown that early-type galaxies (ETGs), traditionally thought of as dispersion-dominated systems, show strong rotation in ~80% of cases. This led to a new kinematic classification of ETGs into fast rotators (strong rotation signature; FRs) and...

Absence of fast radio bursts at intermediate Galactic latitude

The majority of the enigmatic bright pulses called fast radio bursts (FRBs) have been found at high Galactic latitudes. The bursts are thought to originate in distant Galaxies, and the sparser interstellar medium at high latitudes might make them easier to detect. But...