NGC 5408: Hubble Snaps Image of Little-Known Irregular GalaxyJan 18, 2016 by Natali Anderson
The NASA/ESA Hubble Space Telescope has captured an incredible image of the nearby galaxy NGC 5408.
This image from the NASA/ESA Hubble Space Telescope shows the irregular galaxy NGC 5408, which is located 17.4 million light-years from Earth. Image credit: NASA / ESA / Hubble / Judy Schmidt, www.geckzilla.com.
NGC 5408, also known as LEDA 50073, Hen 3-959 and Tol 116, is an irregular galaxy located in the constellation Centaurus, 17.4 million light-years away.
It was first discovered by the British astronomer John Herschel on June 5, 1834.
Astronomers had long mistaken NGC 5408 for a planetary nebula. Instead, bucking labels, NGC 5408 turned out to be an entire galaxy.
In yet another sign of NGC 5408 breaking convention, the galaxy is associated with a brilliant object known as an ultraluminous X-ray source (ULX), namedNGC 5408 X-1.
According to observations by ESA’s XMM-Newton space telescope, NGC 5408 X-1 represents one of the best cases for an intermediate-mass black hole to date.
In 2006 and 2008, XMM-Newton detected what astronomers call ‘quasi-periodic oscillations,’ a nearly regular ‘flickering’ caused by the pile-up of hot gas deep within the accretion disk that forms around a massive object.
The rate of this flickering was about 100 times slower than that seen from stellar-mass black holes. Yet, in X-rays, NGC 5408 X-1 outshines these systems by about the same factor.
Based on the timing of the oscillations and other characteristics of the emission, astronomers concluded that NGC 5408 X-1 contains between 1,000 and 9,000 solar masses.
This composite image of NGC 5408 includes infrared and optical observations from both Hubble’s Wide Field Planetary Camera 2 (WFPC2) and the Wide Field Camera 3 (WFC3).
Astronomer Judy Schmidt submitted a version of the image to the Hubble’s Hidden Treasures image processing competition.