Explanation: Why does this galaxy spin so fast? To start, even identifying which type of galaxy UGC 12591 is difficult -- it has dark dust lanes like a spiral galaxy but a large diffuse bulge of stars like a lenticular. Surprisingly observations show that UGC 12591 spins at about 480 km/sec, almost twice as fast as our Milky Way, and the fastest rotation rate yet measured. The mass needed to hold together a galaxy spinning this fast is several times the mass of our Milky Way Galaxy. Progenitor scenarios for UGC 12591 include slow growth by accreting ambient matter, or rapid growth through a recent galaxy collision or collisions -- future observations may tell. The light we see today from UGC 12591 left about 400 million years ago, when trees were first developing on Earth.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 5:15 am
by Rajesh Kalmady
The light from the galaxy left 400 million years ago, not 400 million light years ago.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 5:34 am
by jonas s
The quoted spin rate as a linear velocity, km/sec. What is the angular rate of spin or is the quoted km/sec at baseline distance from center of rotation?
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 5:44 am
by Ann
What a great picture!
It's fantastic to see that fast rotating, "sterile" dust disk, with no hints of clumps or pockets where stars may form. Instead, the wildly spinning dust is "thin", as if it was stretched thin by its own rotation. Note the reddened background galaxy that can be seen right through the dust ring of UGC 12591 at lower left!
It's a great picture!
Ann
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 6:13 am
by neufer
jonas s wrote:
The quoted spin rate as a linear velocity, km/sec. What is the angular rate of spin or is the quoted km/sec at baseline distance from center of rotation?
Vera Rubin discovered that galaxies rotate, more or less, at a constant linear velocity.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 6:54 am
by Boomer12k
So....smaller? Tighter? Spins a bit faster??? More Dark Matter? Not as much Dark Matter? So less mass to spin?????
:---[===] *
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 8:32 am
by Coil_Smoke
Could be named the 'Race Way' galaxy. That's probably taken ? Kinda sounds familiar. Sure does look like it's spinning fast...Like a 45RPM record, grooves and all. Is all that rotation conserved energy from initial formation? Can energy for all the whirring and spiraling about in this universe extend from higher dimensions?
P.S. WOW... that Pale ghostly Bright Galaxy at extreme upper right in the expanded full resolution version Is quite the SURPRISE! (double click main image, scroll up/right)
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 10:27 am
by De58te
In the expanded view next to the galaxy pointed out by Coil Smoke, there are two neat blue galaxies really close to each other. I wonder if they are colliding?
Also look at the neat all red galaxy just above the ESA letters. I wonder why the galaxy is all red. Could it be due to the expansion of the universe and all the distant galaxies are red shifted because they are moving away from us? There are about 2 or 3 other red galaxies along the bottom, but through the rest of the photograph the galaxies are either white or blue. There are a lot of blue distant galaxies visible. Would those galaxies be blue shifted because they are all moving towards us? That would be at odds with the distant galaxies being red shifted.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 11:13 am
by douglas
Have any lenticular galaxy bulges ever been observed to have expanded or shrank over observation timescales?
And is the bulge's glow only in visual wavelengths? Seems a curious phenomena to only be visual.
Got to be formation artifacts somewhere.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 11:19 am
by Observer 51
M 104 in Virgo seems somewhat similar to this galaxy. I wonder what M 104's rotation rate is relative to UGC 12591's?
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 11:56 am
by Bopps
The orbits of earth satellites are at altitudes defined by their velocity ... higher velocity to maintain higher altitudes. As their velocity decays they eventually fall back to earth. If galaxy objects are at the same linear velocity, they would be "falling" towards the center. Does this explain arms spiraling inward towards the center black hole of galaxies?
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 12:22 pm
by orin stepanek
I name this Galaxy (Zip)!
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 1:05 pm
by neufer
Bopps wrote:
The orbits of earth satellites are at altitudes defined by their velocity ... higher velocity to maintain higher altitudes. As their velocity decays they eventually fall back to earth. If galaxy objects are at the same linear velocity, they would be "falling" towards the center. Does this explain arms spiraling inward towards the center black hole of galaxies?
The (~circular) orbits of earth satellites are at altitudes defined by their velocity
... higher velocities are needed to maintain lower altitudes:
Centrifugal force = mv2/r = gravitational force = GmM/r2
Hence: v2 = GM/r : or v = sqrt (GM/r)
For (~circular) orbital velocity to be constant
the gravitational force of galaxies must drop off more slowly as 1/r not 1/r2.
Centrifugal force = mv2/r = gravitational force = Cm/r (; i.e., total dark mass M grows as Cr/G)
Hence: v2 = C : or v = sqrt (C)
(; i.e., UGC 12591's dark mass density is ~4 times that of the Milky Way.)
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 2:03 pm
by Ann
De58te wrote:In the expanded view next to the galaxy pointed out by Coil Smoke, there are two neat blue galaxies really close to each other. I wonder if they are colliding?
Also look at the neat all red galaxy just above the ESA letters. I wonder why the galaxy is all red. Could it be due to the expansion of the universe and all the distant galaxies are red shifted because they are moving away from us? There are about 2 or 3 other red galaxies along the bottom, but through the rest of the photograph the galaxies are either white or blue. There are a lot of blue distant galaxies visible. Would those galaxies be blue shifted because they are all moving towards us? That would be at odds with the distant galaxies being red shifted.
Well, the two most obvious galaxies that I can see, that are definitely interacting and close to the "pale bright ghost galaxy" at upper right - I like that desciption - aren't blue, but yes, they really seem to be interacting. So yes, they should collide in a few (hundred) million years from now. (And of course, if we could see what these galaxies have evolved into hundreds of millions of years after the light that we can see actually left them - which we can't - we would probably see that they have already collided.)
The very red background galaxies do indeed owe their color to redshift reddening, although it is quite possible that dust reddening also contributes to their color.
The very blue galaxies, by the way, were forming hot bright stars at a furious rate at the time when the light that has reached us left them. At that time they emitted copious amounts of ultraviolet light, which has since been redshiftet into the blue light that we now can see.
Ann
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 2:17 pm
by pipejazz
Numerous galaxies, is this gravational lensing or reality?
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 2:30 pm
by leats
Thank you for providing a reference point relative to earth's evolution for the time the light left this galaxy. I'd like to see this done for all photos of interstellar objects. Staggering numbers like 5 million light years or 1 billion light years... have more meaning (to me) if I can associate them with a period in earth's history.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 2:43 pm
by Chris Peterson
De58te wrote:In the expanded view next to the galaxy pointed out by Coil Smoke, there are two neat blue galaxies really close to each other. I wonder if they are colliding?
Also look at the neat all red galaxy just above the ESA letters. I wonder why the galaxy is all red. Could it be due to the expansion of the universe and all the distant galaxies are red shifted because they are moving away from us? There are about 2 or 3 other red galaxies along the bottom, but through the rest of the photograph the galaxies are either white or blue. There are a lot of blue distant galaxies visible. Would those galaxies be blue shifted because they are all moving towards us? That would be at odds with the distant galaxies being red shifted.
You have to be careful comparing color and redshift. First of all, this isn't a natural color image- the entire visual range is mapped to cyan, and a non-overlapping near IR range is mapped to orange. Second, when you redshift you move otherwise invisible short wavelengths into the visible, and you move otherwise visible longer wavelengths into the IR. The effect that has on perceived color isn't always obvious.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 2:45 pm
by Chris Peterson
pipejazz wrote:Numerous galaxies, is this gravational lensing or reality? :D
Gravitational lensing is reality! But I don't see any obvious lensing in this image. (And the object in this image is much too close to be an effective lens.)
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 3:05 pm
by gadieid
Great photo! I've counted at least 40 other galaxies and that without looking at the high resolution picture.
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 3:08 pm
by RJN
Rajesh Kalmady wrote:The light from the galaxy left 400 million years ago, not 400 million light years ago.
Oops! Yes. Fixed it on the main NASA APOD. Thanks!
- RJN
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 3:25 pm
by neufer
RJN wrote:
Rajesh Kalmady wrote:
The light from the galaxy left 400 million years ago, not 400 million light years ago.
Oops! Yes. Fixed it on the main NASA APOD. Thanks!
<<The earliest tree-like organisms were tree ferns, horsetails and lycophytes, which grew in forests in the Carboniferous period. The first tree may have been Wattieza, fossils of which have been found in New York State in 2007 dating back to the Middle Devonian (about 385 million years ago). Prior to this discovery, Archaeopteris was the earliest known tree. Both of these reproduced by spores rather than seeds and are considered to be links between ferns and the gymnosperms which evolved in the Triassic period. The gymnosperms include conifers, cycads, gnetales and ginkgos and these may have appeared as a result of a whole genome duplication event which took place about 319 million years ago. Ginkgophyta was once a widespread diverse group of which the only survivor is the maidenhair tree Ginkgo biloba. This is considered to be a living fossil because it is virtually unchanged from the fossilised specimens found in Triassic deposits.
During the Mesozoic (245 to 66 million years ago) the conifers flourished and became adapted to live in all the major terrestrial habitats. Subsequently, the tree forms of flowering plants evolved during the Cretaceous period. These began to dominate the conifers during the Tertiary era (66 to 2 million years ago) when forests covered the globe. When the climate cooled 1.5 million years ago and the first of four ice ages occurred, the forests retreated as the ice advanced. In the interglacials, trees recolonised the land that had been covered by ice, only to be driven back again in the next ice age.>>
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 3:42 pm
by rstevenson
Wow! What a view!
I wonder how many of those small round blueish-white spots near the galaxy are its globular clusters? There look to be many dozens of them.
Rob
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
<<ISOHDFS 27 is the most massive spiral galaxy in the Hubble Deep Field South known so far which is 130,000 light-years in diameter. It is approximately 6 billion light years from Earth. It has a mass of 1.04×1012 solar masses (M☉), about four times as massive as the Milky Way.
The preceding most massive spiral was UGC 12591.>>
<<Segue 2 is a dwarf spheroidal galaxy situated in the constellation Aries and discovered in 2009 in the data obtained by Sloan Digital Sky Survey. The galaxy is located at the distance of about 35 kpc (110,000 ly) from the Sun and moves towards the Sun with the speed of 40 km/s. It is classified as a dwarf spheroidal galaxy (dSph) meaning that it has an approximately round shape with the half-light radius of about 34 pc. Segue 2 is located near the edge of Sagittarius Stream and at the same distance. It may once have been a satellite of Sagittarius Dwarf Elliptical Galaxy or its star cluster.
Segue 2 is one of the smallest and faintest satellites of the Milky Way—its integrated luminosity is about 800 times that of the Sun (absolute visible magnitude of about −2.5), which is much lower than the luminosity of the majority of globular clusters. Circa 1,000 stars are supposed to exist within the galaxy. However, the mass of the galaxy—about 550,000 solar masses—is substantial, corresponding to the mass to light ratio of about 650. In June 2013 the The Astrophysical Journal reported that Segue 2 was bound together with dark matter.
The stellar population of Segue 2 consists mainly of old stars formed more than 12 billion years ago. The metallicity of these old stars is also very low at [Fe/H] < −2, which means that they contain at least 100 times less heavy elements than the Sun. The stars of Segue 2 were probably among the first stars to form in the Universe. Currently, there is no star formation in Segue 2.>>
Re: APOD: UGC 12591: The Fastest Rotating... (2017 Mar 07)
Posted: Tue Mar 07, 2017 4:42 pm
by Fred the Cat
Perhaps dark matter is more akin to the grooves on a record album. It keeps the tonearm on track despite its rotational speed.
UGC 12591: The Fastest Rotating Galaxy Known
Vera Rubin discovered that galaxies rotate, more or less, at a constant linear velocity.
