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Sunday, September 2, 2012

Spiral Galaxy NGC 5806 and Supernova SN 2004dg

Spiral Galaxy NGC 5806 and Supernova SN 2004dg
Click on the image for full resolution (3.7 MB)

A new image from the NASA/ESA Hubble Space Telescope shows NGC 5806, a spiral galaxy in the constellation Virgo (the Virgin). It lies around 80 million light years from Earth. Also visible in this image is a supernova explosion called SN 2004dg. The exposures that are combined into this image were carried out in early 2005 in order to help pinpoint the location of the supernova, which exploded in 2004. The afterglow from this outburst of light, caused by a giant star exploding at the end of its life, can be seen as a faint yellowish dot near the bottom of the galaxy. NGC 5806 was chosen to be one of a number of galaxies in a study into supernovae because Hubble's archive already contained high resolution imagery of the galaxy, collected before the star had exploded. Since supernovae are both relatively rare, and impossible to predict with any accuracy, the existence of such before-and-after images is precious for astronomers who study these violent events. Aside from the supernova, NGC 5806 is a relatively unremarkable galaxy: it is neither particularly large or small, nor especially close or distant. The galaxy's bulge (the densest part in the centre of the spiral arms) is a so-called disk-type bulge, in which the spiral structure extends right to the centre of the galaxy, instead of there being a large elliptical bulge of stars present. It is also home to an active galaxy nucleus, a supermassive black hole which is pulling in large amounts of matter from its immediate surroundings. As the matter spirals around the black hole, it heats up and emits powerful radiation. This image is produced from three exposures in visible and infrared light, observed by Hubble's Advanced Camera for Surveys. The field of view is approximately 3.3 by 1.7 arcminutes.
The full resolution image weighs 3.7 MB, so please be patient when downloading!
Credit: ESA/Hubble and NASA
Image enhancement: Jean-Baptiste Faure

1 comment(s):

carinaemajoris said...

This is a very beautiful image Jean! For a comparison let us look at this image of SN2004dg: [http://www.astrosurf.com/snweb2/2004/04dg/04dgHome.htm]. This is also the Rochester University entry: [http://www.rochesterastronomy.org//sn2004/sn2004dg.html]. #Astronomy #SN2004dg

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