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APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Wed Oct 16, 2013 4:02 am
by APOD Robot
Three Galaxies in Draco
Explanation: This intriguing trio of galaxies is sometimes called the Draco Group, located in the northern constellation of (you guessed it)
Draco. From left to right are
edge-on spiral NGC 5981,
elliptical galaxy NGC 5982, and
face-on spiral NGC 5985 -- all within this single telescopic field of view spanning a little more than half the width of the full moon. While the group is far too small to be a
galaxy cluster and has not been
catalogued as a compact group, these galaxies all do lie roughly 100 million light-years from planet Earth. On close examination with
spectrographs, the bright core of the striking face-on spiral NGC 5985 shows prominent emission in specific wavelengths of light, prompting astronomers to classify it as a
Seyfert, a type of active galaxy. Not as well known as other tight
groupings of galaxies, the contrast in visual appearance makes this triplet an attractive subject for astrophotographers. This
impressively deep exposure hints at faint, sharp-edged shells surrounding elliptical NGC 5982, evidence of past galactic mergers. It also reveals many even more distant
background galaxies.
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Re: APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Wed Oct 16, 2013 4:43 am
by Ann
It's a great picture!
Elliptical galaxy NGC 5982 is fascinating. There are indeed sharp-edged shells surrounding it. I think it was David Malin who first demonstrated that very many large elliptical galaxies are surrounded by such shells, evidence that they have grown by mergers.
To me the shells look faintly spiral-shaped. They made me wonder if some presumed ellipticals could be really be face-on disk-shaped lenticulars, perhaps with a hint of residual spiral shape.
Anyway, great image!
Ann
three of my best operators
Posted: Wed Oct 16, 2013 1:19 pm
by neufer
http://jamesbond.wikia.com/wiki/Marc-Ange_Draco wrote:
<<Marc-Ange Draco is the head of one of the most powerful crime syndicates in the world and father of Tracy Bond (therefore Bond's father-in-law). He appears in both the novel and film adaptation of On Her Majesty's Secret Service and is portrayed by Gabriele Ferzetti.
Bond requests Draco and a group of his men within the Union Corse to help him in the attack on Blofeld's mountain hideaway. Upon arriving Blofeld's headquarters, Draco and his men rescue the kidnapped Tracy, and personally knocks his daughter unconscious when she chooses to stay behind for Bond. After Bond and Tracy become newlyweds, Draco acknowledges his meeting of M being "the man who cost me three of my best operators" in which M replies "Yes. November 1964 - The bullion job." most likely referring to the Goldfinger incident.>>
Re: APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Wed Oct 16, 2013 2:46 pm
by geckzilla
I checked the HLA to see if there was any data on NGC 5982. There was! For the purpose of discussing it, I quickly processed the galaxy with minimal contrast adjustment and some sharpening. I'm curious about why the vaguely implied spiral structure is absent in the Hubble data. You can see it in
this Capella Observatory image too but it's much less spiral looking and much more like just another shell demarcation. Apparently some shorter wavelength data is necessary for it to appear. Either way, I think the vague spiral shape is probably an illusion caused by our pattern seeking brains.
Re: APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Wed Oct 16, 2013 3:15 pm
by owlice
I like this little background galaxy; nice color, and interesting shape!
- nicelittlebackgroundgalaxy.JPG (8.71 KiB) Viewed 2639 times
Re: APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Wed Oct 16, 2013 3:44 pm
by Chris Peterson
geckzilla wrote:I checked the HLA to see if there was any data on NGC 5982. There was! For the purpose of discussing it, I quickly processed the galaxy with minimal contrast adjustment and some sharpening. I'm curious about why the vaguely implied spiral structure is absent in the Hubble data.
It looks to me like the HST data is only covering the very center of the object. The two ground-based images show nebulosity out two or three times farther, and that's where the structure shows up.
The picture and brainless thoughts (2013 Oct 16)
Posted: Wed Oct 16, 2013 4:57 pm
by BillBixby
My first thought upon seeing today's APOD was What a Beautiful Image.
My second thought was that we were coming under attack by flying saucers.
Reading that the attackers were 100 million ly away I decided not to worry about the attack at this time and just enjoy the beautiful picture.
Thank you for another beautiful APOD. I did not find it on the mirror site but by clicking on yesterdays posting and clicking on the link for tomorrows picture.
Bill
Re: The picture and brainless thoughts (2013 Oct 16)
Posted: Wed Oct 16, 2013 5:04 pm
by LocalColor
BillBixby wrote:My first thought upon seeing today's APOD was What a Beautiful Image.
My second thought was that we were coming under attack by flying saucers.
Reading that the attackers were 100 million ly away I decided not to worry about the attack at this time and just enjoy the beautiful picture.
Thank you for another beautiful APOD. I did not find it on the mirror site but by clicking on yesterdays posting and clicking on the link for tomorrows picture.
Bill
That is how I found today's image. Some of us need our daily "fix" of APOD!
I agree that today's image is very beautiful.
Re: APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Wed Oct 16, 2013 5:46 pm
by geckzilla
Chris Peterson wrote:geckzilla wrote:I checked the HLA to see if there was any data on NGC 5982. There was! For the purpose of discussing it, I quickly processed the galaxy with minimal contrast adjustment and some sharpening. I'm curious about why the vaguely implied spiral structure is absent in the Hubble data.
It looks to me like the HST data is only covering the very center of the object. The two ground-based images show nebulosity out two or three times farther, and that's where the structure shows up.
You're right, but the HST data covers more than just the very center. A significant portion of the galaxy is covered. The footprint view in the HLA and the orientations of the two images threw me off. The strongly defined shell in question in Stephen's image is at the top side of the Hubble image, nearly touching the edge.
Re: APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Thu Oct 17, 2013 8:02 am
by bactame
Images like this are really beyond words. We live in a place whose dimensions can't be comprehended.
Re: APOD: Three Galaxies in Draco (2013 Oct 16)
Posted: Thu Oct 17, 2013 2:38 pm
by Chris Peterson
bactame wrote:We live in a place whose dimensions can't be comprehended.
We live in a place whose dimensions can be easily comprehended, if only we expand our imagination a little.