Hubble Observes Gas Plume from Galaxy NGC 4388
The NASA/ESA Hubble Space Telescope has captured an image of NGC 4388, a spiral galaxy positioned nearly edge-on from Earth's perspective. This galaxy is located approximately 60 million light-years away within the constellation Virgo and is a constituent of the Virgo galaxy cluster. The Virgo cluster comprises over a thousand galaxies and represents the closest large galaxy cluster to the Milky Way.
Observation of Gas Outflow
The image reveals a gas plume emanating from NGC 4388's nucleus, extending from its disk towards the lower-right section of the frame. This feature was not discernible in a previous Hubble image of the galaxy released in 2016.
Plume Formation and Ionization
Mechanism of Outflow: The presence and characteristics of the gas outflow are attributed to the galaxy's movement within the Virgo cluster's intracluster medium. This medium consists of hot, diffuse gas residing between galaxies. As NGC 4388 traverses this medium, pressure exerted by the intracluster gas strips gas from the galaxy's disk, causing it to trail behind.
Source of Illumination: The ionization causing the gas cloud to glow is under investigation. Researchers propose two primary sources for this energy:
- Galactic Center Activity: A supermassive black hole at the galaxy's center is believed to heat surrounding gas into a disk, emitting radiation that ionizes the gas proximate to the galaxy.
- Shock Waves: Shock waves are hypothesized to be responsible for the ionization of gas filaments located farther from the galactic core.
This specific image incorporates new data, including multiple additional wavelengths of light, which were instrumental in visualizing the ionized gas cloud. The observations contribute to ongoing programs designed to study galaxies containing active black holes.