NGC 1532 - Jabba the hutt learns synchronized swimming

[Placidus]

NGC 1532 looks like a nearly edge-on spiral that's been savagely disrupted by dark forces from its small companion toward 11 o'clock, triggering bright blue streaks of star formation in the spiral arms.

We've always seen something like a frog we once found in the swimming pool filter box, executing lazy aquatic ballet manoeuvres, with long legs trailing out and around. Perhaps there's also an element of Jabba the Hutt.

The thumbnail is cropped to just the galaxy. The main image is here (https://photos.smugmug.com/Category/Astrophotography-at-Placidus/i-dgWw2Zj/0/O/NGC%201532%20Lum%2012%20RGB%202%20h rs%20each.jpg).

The detail in the bright part of the galaxy is adequate, but we're starting to see that the "signature dish" at Placidus is being able to extract sharp detail in the very faintest structure, and we invite your attention to the discrete blue dots in the outermost, almost invisible parts of the spiral arms, and (in the whole image only) in the irregular dwarf galaxy toward 5 o'clock and half way out. There are just hundreds of other small galaxies scattered around the full image.

In the main image (but cropped out of the thumbnail), there is a faint set of diagonal coloured arcs across the lower half, due to brilliant light from upsilon 4 Eridani (well out of field to the bottom right) bouncing off filters. We've done a fair bit of air-brushing to tame these, so please ignore the bottom third of the big image.

Luminance: 12 hrs, RGB: 2 hrs each channel, all in 30 min subs. New moon. Seeing about 2 sec arc. Full field about half a degree. Aspen CG16M on 20" PlaneWave. Processing mostly with GoodLook 64 but evil upsilon 4 Eridani touch-ups with CS5.

This is one of our absolute favourite interacting pairs. Hope you like it too.

Best,
Mike and Trish

[willik]

quality image well done

[strongmanmike]

Excellent guys. Only the faintest of hints but I think I'll just take my medication :help: Overall a super image of a galaxy that has never really made me excited...until now :thumbsup: ..lovely vibrant colour and one can really sense the turmoil going on in the scene. So many interesting features, great stuff guys...I am getting used to worms....I won't even notice them soon :screwy:

Mike

[Stevec35]

Very nice image of one of my favorite galaxies guys

Cheers

Steve

[Andy01]

Wow, the universe keeps on delivering these unique & amazing targets, and your image is terrific!
Well done guys :thumbsup:

[Slawomir]

Magnificent image M&T. Somehow it reminded me of Executor crashing into Death Star :)

[Placidus]

Thanks Martin !



Thanks muchly, Mike. Thought we'd got away with that one. :D



Hi, Steve! Glad you like it.



Thanks Andy!



Thanks Suavi. We're greatly encouraged. :) Rushed to look up Executor and reason for its crash.

[markas]

I like this one! It's a great target very well caught.

Mark

[vlazg]

Stunning M&T......as usual. :thumbsup:

[mountainjoo]

I learn about a new galaxy every time you guys post one, and the interaction seen here is brilliant!

[RickS]

Very classy, M&T! Some sublime detail in there that I've never noticed before. And only the merest traces of annelids ;)

Cheers,
Rick.

[Atmos]

This has got to be one of my favourite images that I've seen come from your observatory! Absolutely an enjoyable image to view :thumbsup:

[gregbradley]

I agree, I like this one a lot. Lovely colour and all those little blue clumps of stars. Do you think they are globs?

I wonder if the LMC distorts arms of the Milky Way in a similar way?
Greg.

[silv]

I enjoy your introductional text as much as your imaging result!

Wow, the big one looks as if it's forming a funnel due to to the secondary galaxy mass closing in on the black hole head on!

And what's the bright blue speck, double star with nebula at 12 o'clock? Does it belong to the outmost spiral arm or is it a separate object?
It seems too bright to be part of the galaxy.. as if the area was actually much closer to our viewpoint.

[Atmos]

It doesn't currently but it will in the future, the Sagitarrius Dwarf Galaxy has caused some minor disruption however. The blue clumps are bouts in intense star formation caused by the interaction between the LMC like object and the main galaxy.

Star formation gets very intense around galactic interactions.

[silv]

keep coming back to the image.
the outstretched arm can't be aiming outward due to the attack of the dwarf? ?
that arm-effect wouldn't be happening if you throw a stone into a sandpit, would it? the sandpit being the big galaxy, of course.

how about it's more like a sling, still pulling material from outside the galaxy into the "gravitational force field" of the big one?
maybe enhanced by the additional forces of the dwarf?

----

and from the "wall" growing upwards in the back (what I called a "funnel" before), we can calculate the direction from which the dwarf is "thrown into the sandpit". so cool. thanks for sharing!

[Slawomir]

I did not notice them at first, but now I do :lol:

Awesome work IMO anyway.

[Placidus]

Thanks, Mark!





Thanks, Jerome. The deformation and star-formation is impressive.



Thrilled that we've shown something a bit different!



Thanks, Colin. We are much encouraged. Makes up for the fact that the roof opening mechanism is trying to tear itself to pieces.



Hi, Greg, and many thanks. Guessing wildly about the possibility of globulars. My vague understanding is that globular clusters should be mostly Population II stars and therefore more orange coloured. There are a couple of extremely blue isolated stars at the top of the full image, far from any others. I secretly hope that they are quasars rather than just rare blue stars in the Milky Way.

I'm aware that there is a very faint bridge of gas and dust between us and the LMC. Colin has a better answer.



Hi, Annette, nice to hear from you. I'd be guessing wildly about the mechanics, but here goes. I'd reckon that the nebulosity is definitely star formation in the spiral arm, but the two bright blue stars seem implausibly too bright to be part of the galaxy. The way to tell would be to do spectroscopy and compare the red shift of the two blue stars with that of the rest of the galaxy.



Thanks for that, Colin. Not sure I'd want to be in a galaxy with really major star formation going on - we'd get fried.



Glad we've captured your imagination, Annette. Wish I could give any sort of an answer. :sadeyes: Sob. But it's fun to speculate.

Best,
Mike (and Trish, who is sitting beside me, processing garden photos of butcher birds just now).

[Placidus]

They help turn the soil.

The image withstood the most astonishing amount of decon and sharpening without going too silly. We suspect without proof that bright targets and very long integration permit more deconvolution than a quick holiday snap.

Thanks again Suavi :)

[alpal]

A fantastic picture Mike & Trish.
The colour in many stars looks a little over saturated to my eye
but apart from that it looks perfect.

cheers
Allan

[gregbradley]

I remember a post a long time ago by Brad Moore who took a long exposure of Eta Carnina. He showed how much extra you could apply unsharp masking with different levels of exposure. It was very clear that sharpening is way more effective on successive longer lengths of exposure.
As you say brightness would be much the same as it would be the signal strength that would be the factor.

Greg.

[Placidus]

Thanks Allan. You're right about the stars being too saturated. I got the colour about right in the RGB image, but messed it up when combining with Lum. Please avert your gaze!



Thanks, Greg, that's helpful.

[PRejto]

M & T, Congratulations for a wonderfully sharp image with very natural looking colour. It is also my favorite interacting pair.

Peter

[Slawomir]

I will need to one day investigate this mysterious technique that everyone is talking about! :lol:

[Geoff45]

The usual good stuff. Well done guys.
I am always intrigued by the fact that it so often happens that a quite small galaxy seems to have an overwhelmingly large effect on the larger one, but the disruption is not reciprocated.

Those out of field star flares are a real bummer. There is almost nothing worse that getting the first decent stretch of an otherwise great image and seeing one of them.

Challenge: There's a nice little "southern cross and pointers" asterism in the pic. See if you can spot it!
Geoff

[Placidus]

Thanks Peter. Nice to hear from you!



One day I would like it if deconvolution just did what it said on the label.



Hi, Geoff,
Glad you like the image. Working hard on reflection removal software. I can perfectly remove a set of perfect concentric rings, but the actual reflections must be off irregular surfaces, because they're more like streaky irregular clouds. It's proving a very difficult project.

Any hints on the Southern Cross? There's a possible candidate near the mega=bright star toward bottom left.

Thanks all.

[Geoff45]

About a third of the way in from the right hand side, bottom edge (2418, 3874)

[SimmoW]

Magnificent team! So much going on here.

I know im a sucker for wider fields/ context shots, but I really think a slightly wider crop to grab some of the other galaxies would perfect this one. Very unique combo here!

[cometcatcher]

That's a cracker. I hope you submitted your image for APOD.

[gregbradley]

Mike I just noticed on my other computer which has more of a blue bias to the monitor that there are blue bands on the bottom right corner of the image that extend to just under the galaxy. What are those? Is that an arc reflection from an out of field bright star? CDKs seem prone to reflections.

Greg.

[Shiraz]

astonishing image with some very fine detail showing and the colour is excellent. Bravo.

[Placidus]

Thanks, Simon!


For your wider field delectation, here is the whole frame (https://photos.smugmug.com/Category/Astrophotography-at-Placidus/i-dgWw2Zj/0/O/NGC%201532%20Lum%2012%20RGB%202%20h rs%20each.jpg).




Thanks, Kevin, most kind. Not game to submit to APOD.



Well spotted, Greg. They are indeed reflections from upsilon 4 Eridani, which is about a degree or so out of field. Why it's worse in blue, I don't know.



Thank you very much, Ray. That is indeed encouraging.

[topheart]

Hi M+T,
Wow! Wow! woooow!

That is the best image I have seen for awhile. I also reckon a potential APOD.
Very well done.

Congratulations!
Regards,
Tim

[Placidus]

Hi, Tim. We're thrilled that you think we're getting there. Many thanks.

[cometcatcher]

Mike, did anyone mention you have Supernova SN2016iae in the shot ?

[strongmanmike]

Sheesh that's funny, I actually noted that star and for some reason actually thought in my head, "Huh..looks like a supernova"..and just brushed it off...similar to when I noticed NGC253-dw2, very similar thought and brushed it off. Should trust my instincts but there is no way of knowing :thumbsup:

Mike

[Placidus]

Millions of thanks, Kevin.

I was so excited, Trish had to feed me glasses of wine to calm me down and big home-baked celeriac chips for nutrition while I searched for it. I understand that you keep your eye out for these things, but brilliant work finding out about it.

SNR marked, and duly submitted to APOD.

Fat chance with all that blue reflection nonsense from upsilon 4 eridani.

[Placidus]

You've got sharp eyes. And a superb memory! Expecting it to be really faint, I had to look it up, find it was AT2016iae, find the coordinates, plate solve, and there it was. I then checked it against Martin Pugh's 2010 shot, and ... all that work for nothing ... it was bleeding obvious. Stood out like the the famous canine counter-current cooling mechanism.

The only surprise is its very warm colour, which could be because it's against (or obscured by) the warm colour of the galactic centre.

[cometcatcher]

Yeah mag 15 is relatively bright. And in a great looking galaxy taken by one of the best out there. Congrats again M&T!

[astroron]

It is increasing in brightness, could get down to about mag14.
The colour does lean to some extinction by dust and gas,siumilar to the sn earlier this year in NGC5128 AKA Cent A.
Nice image.
Cheers:thumbsup:

[Placidus]

:)




Thanks, Ron, that makes sense.

[marc4darkskies]

A great rendition M&T! :thumbsup: Vibrant detail and colour!

Cheers, Marcus

[Placidus]

Thanks, Marcus!

We think it's an improvement on our previous effort from a couple years ago. Accumulated tiny improvements perhaps. Refocus between subs, much longer total exposure, flats using a big electroluminescent panel, statistical outlier rejection, and luck.

The reflection from upsilon 4 eridani is annoying. Tonight we're doing the Flame Nebula, with Alnitak right there in the frame, and no problem with reflections at all in a short test sub. The problem must be only if the source star is a degree or so out of field.

Best,
M & T

[cometcatcher]

That's similar to what I've discovered also. Even when doing terrestrial night photography. If there was a streetlight just out of frame it would flare so I used to put the buggers in the frame to stop it.

[Placidus]

We spoke too soon. See our next post, on the Flame Nebula, which has at least six copies of Alnitak. Rats.