Image Credit & Copyright: Calar Alto Observatory/Vincent Peris/Gilles Bergond.
Holidays are in full swing and you know what we need to contrast the beautiful snow covered Earth; some color! I came across this image some time ago and thought that no better time to show it off then now. It comes to us from the Calar Alto Observatory’s 3.5 meter telescope in Southern Spain and it’s of the beautiful spiral galaxy NGC 7331 and some of its closest friends in the constellation Pegasus (The Winged Horse).
All beauty aside this galaxy had its oddities. Remember earlier in the week we detailed the backward galaxy NGC 4622 that rotates with the points of the galactic arms first? Well this one isn’t that extreme as the arms travel in a normal direction, but the central galactic bulge which usually co-rotates actually rotates in a backward direction from the disk. So far, there is no true consensus as to why this is the case but in the words of NDT, “We have our best people working on it.”
We’re seeing this galaxy at a pretty extreme inclined angle to our line of sight but still if you look closely or blow this image up full size you can see within its spiral arms, the telltale blues and pinks of star formation taking place as well as the thick dust lanes running through them. The classic yellow hue of ancient stars pooled together in the nucleus is obvious, but what may take a little effort to notice a slight wobble in the plane of the galaxy itself which is likely caused by slight tidal interactions. At its center, as usual, a supermassive black hole which like the galaxy itself is similar to the Milky Way’s at about 4 million solar masses.
What about those other galaxies in the image? First, let’s be polite and introduce ourselves to the four main sub galaxies in this image. The elliptical galaxy at far left is NGC 7340, now to the top with NGC 7336, middle with NGC 7335 and the big beautiful spiral at the bottom cataloged as NGC 7337. These galaxies are members of the NGC 7331 Group of Galaxies which is also known as the “Deer Lick Group.” Just as a general gauging, they appear to be about one-tenth the size of NGC 7331 and also about 10 times further beyond. Just imagine those time travel distances and what it would be like to look up from planets around NGC 7331 and see many other big bright galaxies in the night sky.
Anytime you see an image of this galaxy, you may notice that they’re always at least slightly fuzzy and that’s actually because in that particular direction, we’re looking out through a dusty region of the Milky Way.
NAME: New General Catalogue 7331 (NGC 7331), Caldwell 30 (C30).
WHAT IS IT?: Spiral galaxy.
HOW FAR AWAY IS IT?: About 50 million light years.
HOW BIG IS IT?: Roughly 100,000 light years in diameter which is similar to the Milky Way in size. On the night sky it’s roughly 10.5’X4’ arcminutes.
DISCOVERY: William Herschel in 1784.
APPARENT MAGNITUDE?: 10.4.
WHERE IS IT? (General): Constellation Pegasus and the brightest member of the NGC 7331 Group of Galaxies or the “Deer Lick Group.”
WHERE IS IT? (Exact RA/DEC J2000): RA 22h 37m 04.1s / DEC +34° 24′ 56″.
Calar Alto Observatory page for this image: http://www.caha.es/ngc-7331-a-large-spiral-galaxy.html