Releases from NASA, NASA's Galex, NASA's Goddard Space Flight Center, HubbleSite, Spitzer, Cassini, ESO, ESA, Chandra, HiRISE, Royal Astronomical Society, NRAO, Astronomy Picture of the Day, Harvard-Smithsonian Center For Astrophysics, Max Planck Institute for Astrophysics, Gemini Observatory, Subaru Telescope, W. M. Keck Observatory, Fermi Gamma-ray Space Telescope, JPL-Caltech, etc
Credit:ESA/Hubble,NASAand S. Smartt (Queen's University Belfast) Acknowledgement: Renaud Houdinet
The NASA/ESA Hubble Space Telescope observes some of the most
beautiful galaxies in our skies — spirals sparkling with bright stellar
nurseries (heic1403), violent duos ripping gas and stars away from one another as they tangle together (heic1311), and ethereal irregular galaxies that hang like flocks of birds suspended in the blackness of space (heic1114, heic1207).
However, galaxies, like humans, are not all supermodels. This little
spiral, known as NGC 4102, has a different kind of appeal, with its
tightly-wound spiral arms and understated, but charming, appearance.
NGC 4102 lies in the northern constellation of Ursa Major (The Great Bear). It contains what is known as a LINER, or low-ionization nuclear emission-line region,
meaning that its nucleus emits particular types of radiation —
specifically, emission from weakly-ionised or neutral atoms of certain
elements. Even in this sense, NGC 4102 is not special; around one third
of all nearby galaxies are thought to be LINER galaxies.
Many LINER galaxies also contain intense regions of star formation.
This is thought to be intrinsically linked to their centres but just why
is still a mystery for astronomers — either the starbursts pour fuel
inwards to fuel the LINERs, or this active central region triggers the
starbursts. NGC 4102 does indeed contain a starburst region towards its
centre, where stars are being created at a rate much more furious than
in a normal galaxy. This star formation is taking place within a small
rotating disc, around 1000 light-years in diameter and with a mass some
three billion times the mass of the Sun.
A team of astronomers led by Stephen Smartt of Queen's University
Belfast, the Principal Investigator for the observations making up this
image, have spent the last 15 years searching for the progenitor stars
of supernovae in galaxy images like this. A recent review article
explores some of the results from such studies.