IC 5332 The Galactic Corsage

[strongmanmike (Michael)]

Originally Posted by marco

Ohh Yess, like somebody else already said this is (another) spectacular image Mike, surprised too that there are not too many images around of this one but it looks a not-so-easy object to do..
Great processing mate, love it!
Ciao
Marco

Cheers Marco It is quite faint so I guess hard to get a spectacular image to appear but something about it appeals, especially the tightly wound spiral core

Mike

[Bassnut (Fred)]

Very cool Mike, lots of hrs, a grand effort. The 2 hrs of Ha nicely bought up the nebs.

[nandopg]

Hi Mike,
Wow, a Hubble like image. That is a spectacular galaxy view, with a no less spectacular background crowded with distant galaxies.

That is the kind of image to be looked at for a long time, and then looked again and again....

Thanks for sharing this so special image.
Fernando

[strongmanmike (Michael)]

Originally Posted by Bassnut

Very cool Mike, lots of hrs, a grand effort. The 2 hrs of Ha nicely bought up the nebs.

Cheers Fred, 17hrs is a marathon for me these days but with 12" at F3.8 and a sensitive little camera it can do ok

Originally Posted by nandopg

Hi Mike,
Wow, a Hubble like image. That is a spectacular galaxy view, with a no less spectacular background crowded with distant galaxies.

That is the kind of image to be looked at for a long time, and then looked again and again....

Thanks for sharing this so special image.
Fernando

Glad you enjoyed the view Fernando, nice comments like this make the trouble we go to worthwhile

Mike

[madbadgalaxyman (Robert)]

Mr Sidonio, hello there,
madbadgalaxyman here, calling in briefly, for "just one brief landing in astro-land only"......as I am reading nothing but geology and microbiology and soil science.
(madbadgalaxyman mainly studies the dirt, these days!!)

The arms of this galaxy are very LSB, so very very good work by you with your excellent image of a very tough target.

This system is "two galaxies in one", due to its dual spiral structure:

(1) a long and very-symmetric spiral arm pattern , very smooth textured, made up of mainly old stars.

(2) onto the "very old and well-behaved spiral pattern" is superposed a very chaotic, and nearly random, spiral structure of OB stars and HII regions

This galaxy is a brilliant illustration of that dichotomy of spiral structure which exists to some extent in all spiral galaxies;

.......the "old stellar backbone" of a spiral galaxy is subject to a coordinated & long wave of increased density, leading to long and symmetric spiral arms in the mass-dominant distribution of the galaxy's old stars.....

.........while - in contrast - the young material in a spiral galaxy, that is, the dense gas and the recent star formation and the OB stars and HII regions, may (though does not have to) display a completely different and much much more Chaotic spiral pattern, due to the effects of what is known as propagating "stochastic" star formation.

Best regards,
Robert

[madbadgalaxyman (Robert)]

Hello again, Mike and friends,

Check out the pattern of the HII regions.....it traces a completely different pattern than the smooth tight arms.

I wrote the following about IC 5332 in this (edited) email to my favourite professional astronomer:
______________________________

It is likely that this is one of those sub-luminous spiral galaxies
that are about a magnitude or two down on the luminosity of the Milky
Way. It has a low surface brightness, and the contrast of the spiral
structure is low when it is imaged in the optical regime.

The first thing that strikes my eye is the long, small pitch angle,
yellow, smooth-armed spiral pattern in the central region of this
galaxy, which (perhaps) looks like one of the "old stellar spirals" of
the sort that I have been reading about in a series of papers (by you,
David Block, Puerari, Kenneth C. Freeman, etc).......
except that this smooth & long & two-armed pattern is plainly visible
in the optical regime and does not require NIR imaging to "dig it out"
from the confusion of OB stars and dust and other extreme Population I
material.

I have read some of those papers by you and your co-workers on the
"duality" or "dichotomy" of spiral structure in galaxies;
so perhaps, in itself, the symmetric two-armed spiral pattern in the
old stellar disk of IC 5332 is not so remarkable.....though I am
struck by the remarkable length and regularity of the smooth spiral
pattern, and by its low contrast. There does not seem to be any
evident star formation associated with this inner spiral, so perhaps
it is caused by a weak density wave.

But I did get a bit of shock when I compared an optical image of this galaxy with the GALEX image (in FUV and NUV bandpasses) of this galaxy that I accessed using the GalexView interface.

(( authors note: GALEX far-ultraviolet images emphasize nearly-exclusively the very-young stars in a galaxy;
namely, the hot blue overluminous OB stars are shown, and everything else is de-emphasized in FUV images ))

Well, what a colossal contrast!!
This young material in this galaxy has a completely different spiral
pattern. It looks like a very rough and entropic multiple-armed
pattern.
The contrast between the entropic spiral pattern of this young
Population I material and the well-behaved spiral pattern of the old
yellow-colored spiral is incredibly pronounced in this galaxy.
One might conceivably classify this galaxy as an Sa/Sd, in the spirit
of some of Alan Sandage's type assignments in the Carnegie Atlas where
he was unable to assign to a galaxy a single unique Hubble class, and
was therefore forced to classify a specific galaxy as "either this
Hubble type or that Hubble type, or perhaps both types at the same
time".

In summary, from what I have been reading of your work and that of
Block & Puerari etc., it would seem that this is not an entirely
unexpected morphology;
but what a brilliant illustration of the completely different
behaviour of the Population I spiral and the Population II spiral.

While the morphology of IC 5332 is not completely unique, it is
certainly distinctive and I personally have not seen other galaxies
that look just like this one.

________________________

I have the galex FUV image showing the raggedy spiral pattern in the young stars, and also an 8 micron Spitzer image showing the smooth long old spiral.......so I shall display them in this thread when I access another computer.

Cheers, Robert

[madbadgalaxyman (Robert)]

Here is a visible light image, showing the smooth and tightly-wound arm pattern of older stars:


Here is a GALEX ultraviolet (FUV channel plus NUV channel) image, showing the chaotic open multiple-arm spiral pattern in the distribution of the hot young luminous OB stars:

[madbadgalaxyman (Robert)]

Here are two more "pretty pictures" of IC 5332 to illustrate the gigantic difference between its smooth two-armed Tightly Wound spiral structure, and its very chaotic multiple-armed spiral which is much more open
(a more open spiral structure has a greater 'pitch angle' , in the language of professional astronomy)

Firstly, here is an image by the Gemini South Telescope, showing the smooth tightly-wound symmetric spiral at impressively high angular resolution.
(image was Winner of the 2013 Gemini School Astronomy Contest. Credit: Travis Rector and Australian Gemini Office)



Now here is an H-alpha image from the SINGG survey (image in Ha line ONLY, as the stellar continuum light has been subtracted out beforehand)

[deeplook (Markus)]

Hello Michael,

there is nothing more to say than "wow" for me, just amazing how you managed to colourise this faint beauty so well!

Markus

[strongmanmike (Michael)]

Originally Posted by deeplook

Hello Michael,

there is nothing more to say than "wow" for me, just amazing how you managed to colourise this faint beauty so well!

Markus

Cheers heaps Markus

Mike