Chandra Release - August 18, 2022

Visual Description: NGC 4424

The primary image of this release features the galaxy NGC 4424. Here, the galaxy resembles a wispy line of black smoke in a muted pink and dark grey cloud, dotted with specks of light. In this optical light image captured by the Hubble Space Telescope, the wispy black line is presented on a slight angle; lower on our left and higher on our right. The muted pink color is most evident near the center. The hazy dark grey cloud extends to the sides of the image, which represents a field of view about 45,000 light-years wide. NGC 4424 is, in fact, a spiral galaxy. In this image, the galaxy is observed from the side, making the spiral structure less evident like seeing a frisbee from the side. 

 

Below the wispy black line of smoke, just to our left of center, is a translucent purple dot in a white box. This part of the galaxy has been enlarged, and presented in an inset panel. The inset depicts a hot pink tadpole shape; a bulbous top with a tapered tail. Researchers have determined that this object, nicknamed Nikhuli, is a cluster of stars. It is likely all that remains of a small galaxy that collided with NGC 4424 and had most of its stars stripped away. The distinctive tadpole shape of Nikhuli appears to be the result of the gravitational pull of the larger galaxy elongating the otherwise round star cluster.

 

Nikhuli is surrounded by a disk of electric blue light, and backed by blurry red specks. The blue point source of X-rays seen with NASA’s Chandra X-ray Observatory is likely from a supermassive black hole near the center of Nikhuli.