Using data from the CanariCam infrared camera on the Gran Telescopio Canarias, astronomers have created a high resolution map of the magnetic field lines in gas and dust swirling around the supermassive black hole at the center of the Milky Way Galaxy.
A new high-resolution map of the magnetic field lines in gas and dust swirling around Milky Way’s central black. Image credit: Roche et al, doi: 10.1093/mnras/sty129.
The center of almost every galaxy appears to host a black hole, including our own Milky Way Galaxy.
Stars move around the central black hole at speeds of up to 500 million mph (800 million km an hour), indicating that it has a mass of at least a million times our Sun. Depending on how the material flows, some of it may eventually be captured and engulfed by the black hole.
Visible light from sources in the center of the Milky Way is blocked by clouds of gas and dust. Infrared light, as well as X-rays and radio, more freely passes through this obscuring material, so astronomers use this to see the region more clearly.
“Big telescopes like the Gran Telescopio Canarias, and instruments like the CanariCam, deliver real results,” said co-lead author Professor Pat Roche, from the University of Oxford.
“We’re now able to watch material race around a black hole 25,000 light years away, and for the first time see magnetic fields there in detail.”
“This collaborative work is an exciting step forward in our collective efforts to gain a greater understanding of our own Galaxy and Sagittarius A*, the supermassive black hole at the center of it,” added co-lead author Dr. Chris Packham, from the University of Texas at San Antonio.
“It also demonstrates the importance of access to the largest telescopes using advanced cameras/techniques.”
Centered on the supermassive black hole, the new infrared image covers a region about one light year on each side.
The map shows the intensity of infrared light, and traces magnetic field lines within filaments of warm dust grains and hot gas, which appear here as thin lines reminiscent of brush strokes in a painting.
The filaments, several light years long, appear to meet close to the black hole and may indicate where orbits of streams of gas and dust converge.
One prominent feature links some of the brightest stars in the center of the Milky Way.
Despite the strong winds flowing from these stars, the filaments remain in place, bound by the magnetic field within them.
Elsewhere the magnetic field is less clearly aligned with the filaments.
“The new observations give us more detailed information on the relationship between the bright stars and the dusty filaments,” the astronomers said.
“The origin of the magnetic field in this region is not understood, but it is likely that a smaller magnetic field is stretched out as the filaments are elongated by the gravitational influence of the black hole and stars in the Galactic center.”
The results are published in the Monthly Notices of the Royal Astronomical Society.
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P.F. Roche et al. The Magnetic Field in the central parsec of the Galaxy. MNRAS, published online January 16, 2018; doi: 10.1093/mnras/sty129
