Sculptor Galaxy tagged posts

The movement of stars depends mostly on the invisible dark matter halo around a galaxy. Credit: ESO/Digitized Sky Survey 2

By combining data from Hubble and Gaia mission, astronomers have been able to measure the proper motion of 15 stars in the Sculptor Galaxy, the first such measurement outside the Milky Way. Analysis shows an unexpected preference in the direction of movement, which suggests that the standard theoretical models used to describe the motion of stars and dark matter halos in other galaxies might be invalid.

Astronomers have long been able to measure the movement of stars in our ‘line of sight’ (i.e. the movement towards or away from us) by measuring the redshift, which is caused by the Doppler effect...

This Hubble image shows the central region of a spiral galaxy known as NGC 247.

NGC 247 is a small spiral galaxy in the southern constellation of Cetus (The Whale). Lying at a distance of around 11 million light-years from us, it forms part of the Sculptor Group, a loose collection of galaxies that also contains the more famous NGC 253 (otherwise known as the Sculptor Galaxy).

NGC 247’s nucleus is visible here as a bright, whitish patch, surrounded by a mixture of stars, gas and dust. The dust forms dark patches and filaments that are silhouetted against the background of stars, while the gas has formed into bright knots known as H II regions, mostly scattered throughout the galaxy’s arms and outer areas.

This galaxy displays one particularly unusual and mysterious feature—it is not visibl...