Massive stellar halo around NGC 253

[strongmanmike]

Just been playing with recent data and the halo of stars around NGC 253 really is enormous.

Stretched and displayed in negative it makes it clear just how large it is - doubles or triples the size of the galaxy really.

I haven't seen another image anywhere that shows it this large..? Bit of Milky Way cirrus in the sky there too

Massive NGC 253 Halo (http://www.pbase.com/strongmanmike2002/image/147138890/original)

Mike
easily kept amused by data..... :P

[astroron]

Very Nice:thumbsup:
Cheers

[Larryp]

Great image!

[rogerg]

Interesting, sure is an impressive size. Nice deep data :)

[RickS]

Very interesting, Mike! What we normally see is in images is really just the core of the galaxy.

[jjjnettie]

Amazing. One doesn't really think of the "fuzz" around the brighter galaxies as stars. Thanks for the insight.

[allan gould]

Deep, neat and sweet.
Thanks Mike

[Peter Ward]

The extended halo around NGC253 is real and well documented, you have captured this very well. :thumbsup:

But.. sorry, I suspect your flat-fields need re-calibration.

There is vignetting and flux at 2 o'clock in the image you posted: likely this is an instrumentation artifact ( along with the bright corners from the vignetting) .

There is also an interesting s-bend looking feature at lower left!

Could be you have discovered a new neb..or might be an instrument artifact.:question:

Attached your posted image with the proverbial stretched out of it...

[gregbradley]

Very interesting post Mike. Well done on that capture. This is an area of interest to me.

Greg.

[strongmanmike]

Wow that looks awesome Peter, I may very well have discovered something new, thanks for taking the time to analyse my image, you're a champ :thumbsup:

Don't think it is instrument related, the flats I use are fine and along with the huge halo around NGC 253 there is definitely Milky Way Cirrus in there too :thumbsup:

Mike

[strongmanmike]

Cheers Greg, you should have a stretch too and see if you can find the cistern to go with the S-bend P.Ward found :lol:...or maybe he planted it there..:question:

Mike

[Peter Ward]

No plant...and I dread to correct.....lower *left*

Do I get dibs on the "discovery" ?? :)

[strongmanmike]

Why of course Peter, it's all yours, knock yourself out ;)

[Peter Ward]

OK... I have to ask...did you use a polynomial function to auto-flatten the background?

If not, that s-bend feature may well be real!

[strongmanmike]

No polynomial functions but I did use an algebraic inverse to stretch the halo and cirrus. Because the full well capacity is proportional to pixel depth I never thought polynomial functions would work..?

Interesting

Mike

[strongmanmike]

Yes "go the fro" :P

Mike

[prokyon]

Great, never seen before! :thumbsup:

[strongmanmike]

Cheers Werner, yes it is rarely revealed in photos of this galaxy, I am sure it has been gradient removed out a few times too as perhaps the Milky Way Cirrus too..?

Mike

[strongmanmike]

Hey I was having a lend of you in my replies last night, you do put up a large target with your strange manipulations and wild accusations about my images sometimes :lol: but on reflection Peter and given your use of inverse polynomials etc in your processing I would have thought you would know better :shrug:

Grossly stretching the contrast of an already stretched image beyond reasonable levels with the sole intention of revealing minor blemishes, will obviously then grossly exaggerate any tiny variation that may exist across the frame too and cover up the real features like faint galactic cirrus. This of course will happen if you apply such meaningless heavy handed processing to just about any image with such a high contrast stretch and will show tiny fractions of a % variations to be big black areas :screwy:. Try it on Martins latest Crab for example, same thing happens ie the left side of the image becomes all black while the right side is still light and there is a noticeable processing ring around the Crab too but these are completely unnoticeable in the original (and beautiful) image.

Sigh...can't wait for your reply :rolleyes:

Mike

[avandonk]

Fact: Any eight bit image is already posterized.

Fact: Doing anything extreme with an eight bit image will lead to artefacts.

Fact: Any noise can be fitted to a high order polynomial. Why bother when we have FFT's that can quickly show the lack of power functions in the noise/data.


See here and Google further.

http://en.wikipedia.org/wiki/Spectral_density


All of science is about signal to noise.

Sometimes one mans noise is another mans signal. It takes deep knowledge to differentiate the two.

It is akin to finding Osama bin Ladens bearded face in a piece of toast. I prefer to suspect the toaster of magic powers! Not the bread.

Bert

[multiweb]

Photoshop Mask Paint brush stroke diameter 75px feather 10px ;) :P

[strongmanmike]

What??? Nooooooooooooooo dang :doh: I really thought it was an undiscovered Barnard Polynomial Nebula :sadeyes:

He he :thumbsup:

[avandonk]

It has just been brought to my attention that the bread could be the 'magic' bit. In a very private email the distribution of water in the bread could lead to differential toasting. Is this miracle as good as 'the parting of the waters' from Biblical times but at a smaller scale.

Only an idiot would believe this nonsense!

We all know that all bits of toast have pictures of boobies. I even see them in Rorschach test images.

Bert

[Ross G]

An impressive photo Mike.

Doing something new or different always draws criticism, but hey......someone has to have the guts to lead!

Great capture.

Ross.

[strongmanmike]

Cheers Ross, all good :thumbsup:

Mike
and I have a fair gut these days too :help:

[Peter Ward]

Wasn't taking the piss at all Mike....

....I was simply curious in seeing how far out that halo really went.

....hence after I stretched the proverbial out of the data.....which is no reflection/critique on what you uploaded...thought:

1) bit of vignetting....big deal, still a great image.

2) s-shaped structure....:question: humm never seen that before...real or artifact?

So I asked the question.

If it had been real, you would not be the first amateur wielding a CCD to discover a nebula.

I was also going to bet on Green Moon in today's Melbourne Cup. Bugger.

[Peter Ward]

On polynomials:

MaxIm CCD has a cute background flattening routine, that lets you click on some background data point, then does a polynomial fit to flatten the field, based on that data. (not dis-similar to the PEC fit function with PME/PMX mounts)

Suffice to say: it doesn't always get it right.

[strongmanmike]

Ah huh.... ok, well I'm glad that's settled then....:driving: :lol:

[Fabiomax]

Hi Mike,

Wow, what a stuff! but then you have discovered a new halo around the 253? I've never seen a photograph of this alone! Congratulations !
Fabiomax