A new image from the MeerKAT telescope at the South African Radio Astronomy Observatory (SARAO) in Cape Town, South Africa, shows radio emission from numerous phenomena, including outbursting stars, stellar nurseries, and the chaotic region around Sagittarius A*, the 4.3-million-solar-mass black hole that lurks in the center of our Milky Way Galaxy, 25,000 light-years from Earth.
“The inner 652-light-year region of the Galaxy contains a supermassive black hole, significant quantities of molecular gas, and star formation and cosmic ray energy densities that are roughly two orders of magnitude higher than the corresponding levels in the Galactic disk,” said Dr. Ian Heywood from the University of Oxford, Rhodes University, and SARAO, and his colleagues.
“At a distance of only 26,745 light-years, the region presents astronomers with a unique opportunity to study a diverse range of energetic astrophysical phenomena, from stellar objects in extreme environments, to the supermassive black hole and star-formation driven feedback processes that are known to influence the evolution of galaxies as a whole.”
“We present a new survey of the Galactic center conducted with the South African MeerKAT radio telescope.”
The work represents the culmination of 3 years of detailed analysis of a survey conducted during the MeerKAT’s commissioning phase.
Those observations had already led to the iconic inaugural image in 2018 as well as the discovery of a pair of giant radio bubbles, evidence of an explosive outburst from the heart of our Galaxy several million years ago.
Now, the new MeerKAT image is available in its full complexity for detailed study by astronomers worldwide.
The image is based on a mosaic of 20 separate observations using 200 hours of telescope time covering an area of 6 square degrees.
The data were consistently processed to deliver an angular resolution of 4 seconds of arc — the angle subtended by a tall person at a distance of 100 km; or by the width of a fine human hair held at arm’s length — resulting in a 100 megapixel image.
The image reveals new supernova remnants, including a rare almost-perfect spherical example, and radio-emitting magnetized threads — highly-linear structures up to 100 light-years long.
“I’ve spent a lot of time looking at this image in the process of working on it, and I never get tired of it,” Dr. Heywood said.
“When I show this image to people who might be new to radio astronomy, or otherwise unfamiliar with it, I always try to emphasize that radio imaging hasn’t always been this way, and what a leap forward MeerKAT really is in terms of its capabilities.”
“It’s been a true privilege to work over the years with colleagues from SARAO who built this fantastic telescope.”
“The best telescopes expand our horizons in unexpected ways,” said Dr. Fernando Camilo, chief scientist at SARAO.
“It’s a testament to the skill and dedication of our South African colleagues who built MeerKAT that it’s making such remarkable discoveries in one of the most intensively studied corners of the radio sky.”
“The image we’re sharing today is rich with scientific potential, and we very much look forward to further surprises as the astronomical community mines these data for years to come.”
The results appear in two paper in the Astrophysical Journal and the Astrophysical Journal Letters.
I. Heywood et al. 2022. The 1.28 GHz MeerKAT Galactic Center Mosaic. ApJ, in press; arXiv: 2201.10541
F. Yusef-Zadeh et al. 2022. Statistical Properties of the Population of the Galactic Center Filaments: The Spectral Index and Equipartition Magnetic Field. ApJL, in press; arXiv: 2201.10552
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