A sideways spiral galaxy shines in this NASA/ESA image. Hubble Space Telescope image. Located about 60 million light-years away in the constellation Virgo (Virgo), NGC 4388 is a resident of the Virgo galaxy cluster. This enormous galaxy cluster has over a thousand members and is the closest large galaxy cluster to the Milky Way.
NGC 4388 appears to be tilted at a large angle from our vantage point, giving us an almost edge-on view of the galaxy. This perspective reveals an interesting feature that was not visible in previous Hubble image of this galaxy released in 2016: A plume of gas from the galactic core is seen escaping from the galaxy's disk towards the lower right corner of the image. But where did this outflow come from and why does it glow?
The answer probably lies in the vast spaces separating the Virgo cluster galaxies. Although the space between galaxies appears empty, it is occupied by hot balls of gas called the intracluster medium. As NGC 4388 moves within the Virgo Cluster, it plunges into the intracluster environment. Pressure from the hot gas inside the cluster pushes gas out of NGC 4388's disk, causing it to lag behind as NGC 4388 moves.
The source of the ionizing energy that makes this gas cloud glow is more uncertain. Researchers suspect that some of the energy comes from the center of the galaxy, where a supermassive black hole is spinning gas around itself into a superheated disk. The bright radiation from this disk could ionize the gas closest to the galaxy, and shock waves could be responsible for ionizing filaments of gas further away.
This image includes new data, including several additional wavelengths of light that reveal the cloud of ionized gas. The image contains data from several observing programs that aim to illuminate galaxies with active black holes at their centers.
Media Contact:
Claire Andreoli ([email protected])
NASA Goddard Space Flight Center, Greenbelt, MD
