A new composite image combining far-infrared and X-ray data from ESA’s Herschel and XMM-Newton space observatories reveals the details of the supernova remnant W44 and its environment.
SNR W44 is one of the best examples of a supernova remnant interacting with its parent molecular cloud. It is located around 10,000 light-years away in the constellation of Aquila.
The product of a massive star that has already reached the end of its life and expelled its outer layers in a dramatic explosion, all that remains of the stellar behemoth is the spinning core of a neutron star, or pulsar, labeled PSR B1853+01. The object is the bright point to the top left in SNR W44, colored light blue in this image. It is thought to be around 20,000 years old and as it rapidly rotates it sweeps out a wind of highly energetic particles and beams of light ranging from radio to X-ray energies.
The center of the supernova remnant is also bright in X-rays, coming from the hot gas that fills the shell, at temperatures of several million degrees. Dense knots of high-energy emission reflect regions where heavier elements are more commonly found.
At the cooler edge of the cavity, gas is swept up as the supernova remnant propagates through space.
At the top right of the expanding shell, there is a smaller cavity, with the shock from the supernova remnant impacting the bight arc-shaped feature. This region is filled with hot gas that has been ionized by the intense ultraviolet radiation from embedded young massive stars.
The image also reveals the arrowhead-shaped star-formation region to the right of SNR W44, which appears to point to another trio of intricate clouds further to the right and above.
More broadly, a number of compact objects scattered across the scene map the cold seeds of future stars that will eventually emerge from their dusty cocoons. Finally, diffuse purple emission towards the bottom left of the image provides a glimpse of the Galactic plane.