That the universe is expanding has been known for almost a hundred years now, but how fast? The exact rate of that expansion remains hotly debated, even challenging the standard model of cosmology. A research team at the Technical University of Munich (TUM), the Ludwig Maximilians University (LMU) and the Max Planck Institutes, MPA and MPE, has now imaged and modeled an exceptionally rare supernova that could provide a new, independent way to measure how fast the universe is expanding. The studies are published on the arXiv preprint server.

The supernova is a rare superluminous stellar explosion, 10 billion light-years away, and far brighter than typical supernovae. It is also special in another way: the single supernova appears five times in the night sky, like cosmic fireworks, due to a phenomenon known as gravitational lensing.

Two foreground galaxies bend the supernova’s light as it travels toward Earth, forcing it to take different paths. Because these paths have slightly different lengths, the light arrives at different times. By measuring the time delays between the multiple copies of the supernova, researchers can determine the universe’s present-day expansion rate, known as the Hubble constant.

An international team of astronomers has performed multi-wavelength observations of the nearby Araish galaxy to investigate the origin of its radio emission. As a result, they detected an extended radio jet of this galaxy. The finding was reported February 11 on the arXiv pre-print server.

Observations show that powerful radio jets are commonly observed in elliptical galaxies or massive quasars. However, their presence in spiral galaxies is relatively rare. These systems, known as spiral double radio-source associated with galactic nuclei (DRAGNs), are therefore unique galaxies where classical disk morphology coexists with large-scale radio jets.

What if the Milky Way’s central “black hole” isn’t a black hole at all? A new model proposes that an ultra-dense dark matter core could mimic its gravitational pull.

One of the brightest stars in the Andromeda galaxy quietly collapsed into a black hole without any of the fanfare of a spectacular supernova.

What makes this startling discovery even more remarkable is that the first signs of the transformation were recorded back in 2014 – data that is crucial for understanding the different ways black holes can form after the death of a giant star.

“This has probably been the most surprising discovery of my life,” says astronomer Kishalay De of Columbia University in the US, who led the research. “The evidence of the disappearance of the star was lying in public archival data, and nobody noticed for years until we picked it out.”