SDSS tagged posts

A team of researchers from EPFL have found a way to use the phenomenon of strong gravitational lensing to determine with precision – about 3 times more precise than any other technique – the mass of a galaxy containing a quasar, as well as their evolution in cosmic time. Knowing the mass of quasar host galaxies provides insight into the evolution of galaxies in the early universe, for building scenarios of galaxy formation and black hole development. The results are published in Nature Astronomy.

“The unprecedented precision and accuracy achieved with gravitational lensing provide a new avenue for obtaining robust mass estimates in the distant Universe, where conventional techniques lack precision and are susceptible to biases,” says EPFL astrophysicist...

The latest data release from the Sloan Digital Sky Survey (SDSS) includes observations revealing the internal structure and composition of nearly 5,000 nearby galaxies observed during the first three years of a program called Mapping Nearby Galaxies at Apache Point Observatory (MaNGA).

MaNGA uses a technique called resolved spectroscopy to study galaxies in much greater detail than previous surveys. Spectroscopy is a powerful tool for astronomers, yielding a wealth of information by measuring how much light an object emits at different wavelengths...

Size comparison of a dwarf galaxy (right inset, bottom) with a larger galaxy in the centre. Top inset: Dwarf galaxy overlain with some of the MaNGA data, revealing the winds from the supermassive black hole. Credit: Samantha Penny (Institute of Cosmology and Gravitation, University of Portsmouth) and the SDSS collaboration

Scientists have solved a cosmic mystery by finding evidence that supermassive black holes prevent stars forming in some smaller galaxies. These giant black holes are over a million times more massive than the sun and sit in the centre of galaxies sending out powerful winds that quench the star-making process...

Slice through the celestial equator showing the radial component of the velocity field (in kilometres per second). Blue regions are falling towards us and red regions are flying away from us. Galaxies of the Sloan Digital Sky Survey main galaxy sample are overplotted. In the centre of the slice, the infalling dynamics of the Sloan Great Wall, one of the largest structure of the known universe, can be observed. Credit: University of Portsmouth

New maps of dark matter dynamics in the Universe have been produced by a team of international cosmologists.Using advanced computer modelling techniques, the team has translated the distribution of galaxies into detailed maps of matter streams and velocities for the first time...