Abell2744 galaxy cluster - Pandora's cluster

[Shiraz]

Abell 2744 is one of the Hubble Frontier Fields - regions selected for very deep study using gravitational lensing. The linked image shows the region surrounding the Hubble region, as well as the cluster core - most of the tiny spots of light are far off galaxies - there are only a few stars in this part of the sky.

The redshift of the galaxies in the main core is z=0.308, which means that this light has been travelling about 3.25 billion years - so it started out when simple life was just getting going here on earth. The redshift moves some near-UV absorption bands into the blue in the current universe, which is why many of the galaxies have a yellow/orange cast. I cannot get my head around the distances involved (photons can go a long way in 3 billion years, travelling at 300,000 km every second) - and it is mind boggling that every small galactic spot represents the light from about 100,000,000,000 stars.

The cluster is probably the result of the collision of 4-5 smaller clusters and the visible stuff accounts for only about 5% of the mass (ultra-hot gas and dark matter the rest). This much mass forms a strong gravitational lens, but local seeing does not permit enough resolution to see any of the many small arcs. I am pretty well at the stray/sky light limit for my system - galaxies are readily detectable down to a little deeper than Vmag 23, but there is probably not much more available.

The image has a fair bit of noise (ie is pretty ugly) in order to maximise the bottom end dynamic range and the scale has been increased to 120% to improve the visibility of smaller objects.

I had great fun imaging this region - hope you find it interesting. Thanks for looking. Regards Ray

High res selectable at http://astrob.in/217181/0/
or directly at http://www.astrobin.com/full/217181/0/?real=&mod=

don't bother with the thumbnail below- you won't see anything

[clive milne]

Absolutely flawless.

Love it.

[AlexN]

Outstanding. Love your work on this

[alistairsam]

wow, that's amazing Ray. Love it.
noise, what noise? just beautiful.

Cheers
Alistair

[Placidus]

Awesome! The cluster of red galaxies in the centre stands out beautifully. And such distance! The rest of the frame has some interesting creatures in it too.

(Possible typo: The post says 2744 but the links say 2667.)

Splendid work.

[Shiraz]

Hi Clive - thanks very much.


thanks a lot Alex


ah...well, there is a bit, but thanks very much anyway :)


Thanks very much M&T. hopefully the typo has been fixed - thanks for pointing it out. am currently working on 2667 as well.

regards ray

[alistairsam]

What was the length of the subs Ray and how many?
was this from a dark site?
what's the faintest magnitude galaxy/object in this image?

Cheers
Alistair

[Paul Haese]

Faint suckers. Reminds me of the words. In a galaxy a long time ago. I wonder if there are beings looking back this way wondering the same thing.

[RickS]

Great stuff, Ray! It's good to bump against the limits :thumbsup:

[Shiraz]

Hi Alistair. taken from a rural township - sky about a mag brighter than dark (guess) along with with a neighbour's always-on outside light and a pesky streetlight that almost gets the solar panels working.
190xL 44xB 36xG 44xR all 5 minutes.
According to SIMBAD (if I read it right), the limit is around mag23 (V) - see attachment. Not real deep, but enough to show some detail.


yes I agree, some of the stuff out there can only bring a sense of wonder - what other hobby even comes close.


Thanks Rick - Hubble images quickly show just how limited our ground-based systems are - but it sure is fun to push things a bit.

[gregbradley]

A fabulous image Ray. Its hard to imagine all those dots are galaxies.

Greg.

[strongmanmike]

Very cool image Ray, few outside the astro community would really understand the sheer enormity of such an image, congratulations and thanks for having a shot at it :) Your work is such an inspiration, you plug away like the rest of us with rather modest equipment in a modest setting but manage to produce some of the best work coming out of OZ and without spending lifetimes on data collection, well done :thumbsup:

Mike

[Shiraz]

thanks Greg. it sure is breathtaking to realise what this sort of image shows - I find it very difficult to comprehend.



Very generous Mike :) - it is a very productive community to be part of. This image won't win any prizes and no-one will go OOH when they look at it. But I feel very lucky to be alive when we can afford equipment that will allow us to peer at and vaguely understand some of the bare bones of the universe - even if imperfectly. how much fun is that :thumbsup:.

Back on earth though, it would be nice to find somewhere with reliably good seeing. I have 5 hours of data from last night with 5-6 arcsec blobs in it :lol:.

regards Ray

[codemonkey]

Not much to say other besides what's been said already; great work Ray!

[strongmanmike]

I did :D

Tell me about it :rolleyes: ...ah sigh, the dreaded pom pom stars...:scared:

[Paul Haese]

Yep those northerlies last night produced lovely sized stars even in NB for me. FWHM readings were in the 4-5's for the RC. Urgh! Even the AOX cannot produce miracles in poor seeing. A rarity from my location but it does happen from time to time.

[CosmicEcho]

Err, umm - how can an AOX produce miracles in poor seeing?

[Shiraz]

thanks very much Lee.


yep, they leave a lot to be desired:P


It was pretty ropey seeing up this way - looked like turbulence from the Snowtown windfarm.:lol:

I think that Paul was making the point that AOX cannot help when seeing is poor - current AO works best in good seeing.

regards Ray

[Paul Haese]

Someone I know has a 30" at Black Springs and he reckons the wind farm nearby has resulted in very poor seeing there some nights.

I don't have any such excuse other than the hills zone is 40km from me and a northerly will create eddies but I did not think it would travel that far.

And; yes I was being facetious about the AOX not being able to help in crap seeing. Rounds stars but not tight. Detail not tight either.

[alpal]

fantastic image Ray,
I looked at it for ages - there are galaxys everywhere.
Please do more like that.

cheers
Allan

[Shiraz]

thanks very much Allan. I still look at it on and off as well - it sure is a fascinating region. Even around the central cluster, there are a couple of hundred galaxies and there are little fuzzy dots all over the place.

regards ray

[rustigsmed]

that is an amazing image Ray and beautifully framed with the galaxy top left and brighter stars drawing you into the centre of the galaxy vortex!

Russ

[SkyViking]

Fabulous image Ray, I never get tired of these deep galaxy cluster shots - the vastness is very humbling. Great processing, I like the very natural look.:thumbsup:

[Shiraz]

thanks very much Russ.


thanks a lot Rolf. I agree, the universe is mind numbingly vast and puts our puny presence in perspective. It is just so interesting to be able to dig around in some fairly distant parts of it. Just for interest, there is a pale blue galaxy at about 1 o'clock from the central star and that is a dead ringer (from the Hubble image) for the blue galaxy in your 2667 image - it seems that there are occasional galaxies in the process of being torn apart in these dense clusters.

regards Ray

[Rac]

This is an awesome image. Very well processed. I find the background perfect.

[topheart]

I found this awe inspiring!

Thanks!!

Tim

[Shiraz]

thanks Raymond - appreciate your comments



Hi Tim - thanks very much.

regards ray

[Shiraz]

Just had a play with the Drake equation Paul. Using some fairly conservative estimates for the unknowable parameters suggests that there may have been more than 1000 civilisations roughly like ours looking back this way from this bit of the sky when the light from Abell 2744 started out. Of course that was over 3 billion years ago, so they may not be there now :lol: . Furthermore, when they looked this way, there were not even some photons from the sun to see, since light from the time of the solar system formation would not have got out there until relatively recently.