Halo tagged posts

A team of researchers at the International Center for Relativistic Astrophysics has found evidence that suggests Sagittarius A* is not a massive black hole but is instead a mass of dark matter. In their paper published in the journal Monthly Notices of the Royal Astronomical Society: Letters, the group describes the evidence they found and how it has stood up to testing.

For several years the scientific community has agreed that there is a mass at the center of the Milky Way galaxy and that the mass is a supermassive black hole—it has been named Sagittarius A*. Its presence has never been verified directly, however, instead it has been inferred by noting the behavior of bodies around it...

ESA’s XMM-Newton has discovered that gas lurking within the Milky Way’s halo reaches far hotter temperatures than previously thought and has a different chemical make-up than predicted, challenging our understanding of our galactic home.

A halo is a vast region of gas, stars and invisible dark matter surrounding a galaxy. It is a key component of a galaxy, connecting it to wider intergalactic space, and is thus thought to play an important role in galactic evolution.

Until now, a galaxy’s halo was thought to contain hot gas at a single temperature, with the exact temperature of this gas dependent on the mass of the galaxy.

However, a new study using ESA’s XMM-Newton X-ray space observatory now shows that the Milky Way’s halo contains no...

Composite image of an edge-on spiral galaxy with a radio halo produced by fast-moving particles in the galaxy’s magnetic field. In this image, the large, grey-blue area is a single image formed by combining the radio halos of 30 different galaxies, as seen with the Very Large Array. At the center is a visible-light image of one of the galaxies, NGC 5775, made using the Hubble Space Telescope. This visible-light image shows only the inner part of the galaxy’s star-forming region, outer portions of which extend horizontally into the area of the radio halo. Credit: Jayanne English (U. Manitoba), with support from Judith Irwin and Theresa Wiegert (Queen’s U.) for the CHANG-ES consortium; NRAO/AUI/NSF; NASA/STScI (Science credit: Theresa Wiegert, Judith Irwin and the CHANG-ES consortium)

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