Using ESA’s XMM-Newton X-ray observatory, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) and its Chandra X-ray Observatory, astronomers have observed the inner eastern lobe of a complex supernova remnant called Westerhout 50.
Multi-wavelength image of Westerhout 50 (red – radio, green – optical, yellow – soft X-rays, magenta – medium energy X-rays, cyan – hard X-ray emission). The eastern lobe X-ray image highlights the XMM-Newton data (with the brightening at the edge of the field of view cropped here to highlight the source emission). The western lobe X-ray image shows only partial Chandra coverage of part of the nebula. Image credit: Safi-Harb et al., arXiv: 2207.00573.
Also known as W50 or SNR G039.7-02.0, Westerhout 50 is located approximately 5,500 parsecs (18,000 light-years) away in the constellation of Aquila.
It is one of the largest known supernova remnants in our Galaxy, over 200 x 100 parsecs (652 x 326 light-years) across.
Westerhout 50 was created when a giant star exploded around 30,000 years ago, flinging its shells of gases out across the sky.
Dubbed the Manatee Nebula for its radio appearances, the supernova remnant’s unique morphology is likely the result of its interaction with the jets from the microquasar SS 433, an eclipsing binary system with the primary being a stellar-mass-sized black hole.
Westerhout 50 attracted attention in 2018 when the High-Altitude Water Cherenkov Observatory, which is sensitive to very high energy gamma-ray photons, revealed the presence of highly energetic particles, but could not pinpoint from where within the supernova remnant the particles were originating.
In new research, University of Manitoba astronomer Samar Safi-Harb and colleagues found the region of particle acceleration in the X-ray jet blasting from the Manatee’s head, which begins about 100 light-years away from the microquasar and extends to approximately 300 light-years.
“Thanks to the new XMM-Newton data, supplemented with NuSTAR and Chandra data, we believe the particles are getting accelerated to very high energies in the head of the Manatee through an unusually energetic particle acceleration process,” Dr. Safi-Harb said.
“The black hole outflow likely made its way there and has been re-energized to high-energy radiation at that location, perhaps due to shock waves in the expanding gas clouds and enhanced magnetic fields.”
“The nebula acts as a nearby laboratory for exploring a wide range of astrophysical phenomena associated with the outflows of many Galactic and extragalactic sources and will be subject to further investigation.”
“Furthermore, follow-up studies by ESA’s future Athena X-ray observatory will provide even more sensitive details about the inner workings of this curious cosmic Manatee.”
The study will be published in the Astrophysical Journal.
Samar Safi-Harb et al. 2022. Hard X-ray emission from the eastern jet of SS 433 powering the W50 ‘Manatee’ nebula: Evidence for particle re-acceleration. ApJ, in press; arXiv: 2207.00573