The NASA/ESA Hubble Space Telescope has captured a striking new photo of a jellyfish spiral galaxy called JW39.
This Hubble image shows JW39, a jellyfish galaxy some 900 million light-years away in the constellation of Coma Berenices. The color image was made from separate exposures taken in the visible, near-infrared and ultraviolet regions of the spectrum with Hubble’s WFC3 instrument. Six filters were used to sample various wavelengths. The color results from assigning different hues to each monochromatic image associated with an individual filter. Image credit: NASA / ESA / Hubble / M. Gullieuszik / GASP Team.
Understanding the physical conditions that lead to the formation of new stars, and conversely to the halting of the star formation activity, is central for astrophysics.
Galaxy disks are the usual cradle for star formation. This is a hierarchical process traced by star-forming regions, dubbed clumps, which are ubiquitous in star-forming galaxies.
Distant galaxies are dominated by bright clumps, which are larger and more massive than in the local Universe.
The star formation activity is strongly influenced and can be even halted by a number of processes, some of which are directly related to the environment in which the galaxy resides.
Ram pressure stripping, i.e. the removal of interstellar gas from the disk of star forming galaxies due to the hydrodynamical interaction with the hot intergalactic medium, is one such process and it is believed to have a strong impact on galaxy populations in dense environments such as galaxy groups and, especially, clusters.
“Despite this jellyfish galaxy’s serene appearance, it is adrift in a ferociously hostile environment — a galaxy cluster,” Hubble astronomers said in a statement.
“Compared to their more isolated counterparts, the galaxies in galaxy clusters are often distorted by the gravitational pull of larger neighbors, which can twist galaxies into a variety of weird and wonderful shapes.”
“If that was not enough, the space between galaxies in a cluster is also pervaded with a searingly hot plasma known as the intracluster medium.”
“While this plasma is extremely tenuous, galaxies moving through it experience it almost like swimmers fighting against a current, and this interaction can strip galaxies of their star-forming gas.”
“This interaction between the intracluster medium and the galaxies is called ram-pressure stripping, and is the process responsible for the trailing tendrils of this jellyfish galaxy.”
“As JW39 has moved through the cluster the pressure of the intracluster medium has stripped away gas and dust into long trailing ribbons of star formation that now stretch away from the disk of the galaxy.”
JW39 is located approximately 900 million light-years away in the constellation of Coma Berenices.
It is one of several jellyfish galaxies that Hubble has been studying over the past two years.
The astronomers used Hubble’s Wide Field Camera 3 (WFC3) to study JW39’s trailing tendrils in detail, as they are a particularly extreme environment for star formation.
“Surprisingly, we found that star formation in the ‘tentacles’ of jellyfish galaxies was not noticeably different from star formation in the galaxy disk,” they said.
