The Communications Center: Breaking Science News • Magnetic loops around the supermassive black hole of NGC 1068

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NGC 1068 is a well-known, relatively nearby, bright galaxy with a supermassive black hole at its center. A few light-years in diameter, the outer accretion disk is dotted by hundreds of distinct water maser sources that hinted for decades at deeper structures. Masers are distinct beacons of electromagnetic radiation that shine in microwave or radio wavelengths; in radio astronomy, water masers observed at a frequency of 22 GHz are particularly useful because they can shine through much of the dust and gas that obscures optical wavelengths.
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By measuring the polarization of water masers as well as the continuum of radio emissions from NGC 1068, the team generated a map revealing the compact radio source now known as NGC 1068* as well as mysterious extended structures of more faint emissions. Mapping the astrometric distribution of NGC 1068 and its water masers revealed that they are spread along filaments of structure. "It really came out in these new observations, that these filaments of maser spots line up like beads on a string" .
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The team was stunned to see that there's a clear offset—a displacement angle—between the radio continuum showing the structures at the galaxy's core and the locations of the masers themselves. "The configuration is unstable, so we are probably observing the source of a magnetically-launched outflow." The measurements of the polarization of these water masers revealed striking evidence of magnetic fields. "No one has ever seen polarization in water masers outside of our galaxy," Gallimore emphasized. Similar to the looping structures seen on our sun's surface as prominences, the polarization pattern of these water masers clearly indicates that magnetic fields are also at the root of these light-year-scale structures as well. "Looking at the filaments, and seeing that the polarization vectors are perpendicular to them, that's the key to confirming that they are magnetically driven structures."
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Their findings reveal evidence of a compact central radio source (the galaxy's supermassive black hole), clear polarization of the water masers indicating structure within NGC 1068's magnetic fields, and spectacular extended features across the continuum of radio frequencies. Together, these findings indicate that magnetic fields are the underlying drivers of these phenomena. Plenty of mysteries remain, however. Within the radio continuum map, for instance, there is a diffuse, faint protrusion that the team nicknamed "the foxtail," which extends northward from the central region.


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Statistics: Posted by AVAO — Sat Jan 04, 2025 8:37 am — Replies 0 — Views 42