The NASA/ESA Hubble Space Telescope has captured a striking new photo of a barred spiral galaxy called NGC 4394.
This Hubble image shows NGC 4394, a barred spiral galaxy located 53.8 million light-years away from Earth, in the constellation Coma Berenices. Image credit: NASA / ESA / Hubble / Judy Schmidt, www.geckzilla.com.
NGC 4394, otherwise known as LEDA 40614, SDSS J122555.63+181250.1 or UGC 7523, was discovered in 1784 by German-born British astronomer William Herschel.
It lies in the constellation of Coma Berenices at a distance of 53.8 million light-years.
The galaxy is considered to be a member of the Virgo Cluster, a collection of about 1,300 – and possibly up to 2,000 – galaxies that form the heart of the Virgo Supercluster.
According to astronomers, NGC 4394 is the archetypal barred spiral galaxy, with bright spiral arms emerging from the ends of a bar that cuts through the galaxy’s central bulge.
These arms are peppered with young blue stars, dark filaments of cosmic dust, and bright, fuzzy regions of active star formation.
NGC 4394’s central region is a good example of what is known as a LINER.
LINERs (Low-Ionization Nuclear Emission-line Regions) are active regions that display a characteristic set of emission lines in their spectra- mostly weakly ionized atoms of oxygen, nitrogen and sulfur.
Although LINER galaxies are relatively common, it’s still unclear where the energy comes from to ionize the gas.
In most cases it is thought to be the influence of a black hole at the center of the galaxy, but it could also be the result of a high level of star formation.
In the case of NGC 4394, it is likely that gravitational interaction with a nearby neighbor has caused gas to flow into the galaxy’s central region, providing a new reservoir of material to fuel the black hole or to make new stars.
This color image of NGC 4394 (hi-res version) was made from separate exposures taken in the visible and infrared regions of the spectrum with both Hubble’s Advanced Camera for Surveys (ACS) and its Wide Field Planetary Camera 2 (WFPC2).
