The Hubble team has released a stunning photo taken by the NASA/ESA Hubble Space Telescope of a galaxy known as NGC 4639.
This Hubble image shows the barred spiral galaxy NGC 4639. Image credit: NASA / ESA / Hubble.
NGC 4639, also known as UGC 7884 or PGC 42741, is a barred spiral galaxy located in the constellation Virgo, about 72 million light-years from Earth.
The galaxy is a member of the Virgo Cluster, a group of about 1,500 galaxies that form the heart of the Virgo Supercluster.
The galaxy’s spiral arms are sprinkled with bright regions of active star formation. Each of these small jewels is actually several hundred light-years across and contains thousands of young stars.
Among them are older, bright stars called Cepheids, which are used as reliable milepost markers to obtain accurate distances to nearby galaxies. Scientists measure the brightness of these stars to calculate the distance to a galaxy.
In June 1990, astronomers spotted a bright Type Ia supernova, named SN 1990N, in NGC 4639.
The galaxy also conceals a dark secret in its core – a supermassive black hole that is consuming the surrounding gas. This is known as an active galactic nucleus (AGN), and is revealed by characteristic features in the spectrum of light from the galaxy and by X-rays produced close to the black hole as the hot gas plunges towards it.
NGC 4639 is in fact a very weak example of an AGN, demonstrating that AGNs exist over a large range of activity, from galaxies like NGC 4639 to distant quasars.
This color image was made from separate exposures taken in the visible, UV and near-IR regions of the spectrum with Hubble’s Wide Field Camera 3.
