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A Map of the Universe, 10 Years In the Making
gabbo529 writes "Astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) have created a map of the universe called the 2MASS Redshift Survey. The astronomers put in 10 laborious years in creating the map and it is what they call the most complete 3-D map of the local universe (out to a distance of 380 million light-years) ever created. 2MASS Redshift Survey extends closer to the Galactic plane than any other map of the universe before it; the region is generally obscured by dust."
What you're saying is its ten years out of date?
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
Empire space is bigger than I thought.
The map is not ten years out of date.
It is 380 million years out of date, in places.
Instead, it took ten years to find out how out of date it really was.
This is awesome!! Here we go astrophysics lab in star trek!!
is like saying a map of downtown Boise is a map of the USA
If that is correct, does green mean on the same vector?
Also, it would appear that the universe within 380 millions years was not expanding but contracting, at least it appears to have more blue to me than red.
What would be neat is if they re-did the map with positions adjusted for the "redshift" where you could compare by toggling quickly back and forth, to get an idea of how much difference there is between what we see due to speed of light and the time for it to hit our eyes from the star, and what we believe to actually be said positions from redshifting. Even more awesome would be a time slider where the colors changed to red/blue if the relative vector changed.
But then, while they say 3d, I only see a 2d image, so I don't know if they've actually mapped out positions in 3d space or just merely color coded the redshift. If that took ten years, I guess we'll have to wait for quantum computers to do all of the heavy lifting automagically.
Like a city whose walls are broken down is a man who lacks self-control.
You are here.
Now all it needs is a microscopic dot on a microscopic dot labeled "You are here"
I'm trying to teach myself to set people on fire with my mind... Is it hot in here?
I think these are the (Coral Cache 'd) download links for the data. Please don't abuse them directly (i.e. go through Coral Cache):
The 6dF Galaxy Survey Redshift Catalogue Data Release 3 (final) catalogue file ... (124703 entries in all)
http://www-wfau.roe.ac.uk.nyud.net/6dFGS/6dFGSzDR3.txt.gz
a comma-separated file the table of spectral observations, a subset of parameters is provided .. and the Coral cached main page for the database:
http://www-wfau.roe.ac.uk.nyud.net/6dFGS/spec_dr3.csv.gz
http://www-wfau.roe.ac.uk.nyud.net/6dFGS/
They released it as a DOOM map?
Supposing the data hasn't been put online somewhere (and from another comment to your post, it looks like it has), I'm certain the researches themselves could be contacted for the data you seek. Publicly funded research usually requires data release upon request.
I mean, for fuck's sake, give me the vector coordinates and I'll make a shit load of files for everyone who wants to view the data in actual 3D -- .blend, .obj, .3ds and several levels for Alien Arena. Hell I have a script that already does this for point clouds (esp. for Kinect) that I can adapt in about 10 minuets. WAD?! (where's all the data?)
Oh sure YOU created a 3D map -- please, no -- you measured the 3D coordinates. Give them to us so we can actually see it -- Oh, I forgot, the purpose of today's research agencies and universities is to charge exorbitant fees for basic knowledge.
The bullshit 3D movies they'll come out with will pale in comparison to the crowd soured galaxy naming/classifying cross reference websites we could make -- if only they weren't Data Nazis. Of course we could suggest more red-shift surveys based on interesting imagines obtained from the Hubble and other telescopes -- Imagine being able to actually map the galaxy by virtually flying around in it, and having beautiful annotated pictures and comments appearing as you approach select parts...
I could reverse engineer their bullshit 2D map, but that would be a waste of time since they have the 3D coordinates they used to plot the map.
Knowledge like this is only of value if it's made free (as in freedom).
word.
Be seeing you...
Some of those stars must have monsters wielding plasma rifles, right?
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
There be Borgs.
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
http://www.shatters.net/celestia/
I hope this gets mapped into STO
Give me a dataset I can import into a spacial database to query the distance between the moon and alpha centauri to the centimeter as of last tuesday adjusted for motion over duration of travel then I'll be impressed. Seriously, I want to make a time-lapse video of that helium-filled sex doll I released at the rapture party through my telescope.
Here you go. Dipshit.
We need to see this in Celestia!
Does the internet accept the challenge?
-- the only thing we have to fear is really scary things
It's a little hard to tell from these images, but the videos I saw on a documentary show really well a concentration along web-like lines. Maybe neural connections are a better analogy. Pretty amazing that the universe isn't a homogenous mixture of galaxies.
I swear to God...I swear to God! That is NOT how you treat your human!
I have a map of the Universe, it's actual size. It says One Megaparsec = One Megaparsec.
Or even worse, it says One Kessel Run = Less Than Twelve Parsecs.
Lil' Thindime, lilting a lacrimose lament, krashes the kwaint konfines of Kokonino Kounty
+1 on this. I swear all these video games / tv are making people angry, impatient and just mean spirited.
Why is there a big empty space near the "equator" of the picture?
After clicking that link, it's still a bit of a trudge for a non-expert in astronomy to find a good/best set of point data (such as might be useful to someone expert in graphics and/or 3D.. as I'm sure there are many here). Has anyone figured this out?
And of course I'm in agreement that the grandparent was excessively rude (I can sympathize in the respect that to us, it is frustrating that the most useful data is often either not shared or is hidden deeply away as an aside. It really should be shared most prominently, as it would affect the public in a much greater way after a short time as the masses find interesting ways to process the data.. but there is no excuse for that sort of behavior).
While the GP misdiagnoses it, there is a problem.
Consider:
() The scientific literature is still far from being all open access.
Astronomy is great, with its preprint culture. Education research is surprisingly among the worst. "Oh, you wish to {teach your child, edit wikipedia, blog about} _physics_? That will be $$ per year or $$ per article here you wish to skim. Oh, math too? That will be..." Also, people are more likely to hear about papers in prestige journals, which are more likely to be paywalled. And as "research paper blogging" increases, and more people look at literature, more encounter the problem. Which all sucks to a degree easily forgotten if you have an "in" through the wall.
() At the time news stories happen, the data is often still being mined, and thus not easily available. So the one time people widely hear about a project, they can't get at the data. And no one ever invests the time to derive a mangled dataset, useless for science, but useful for curiosity or science education.
But there are more puzzling problems. What's going on in the following case?
() There is much institutional and community interest in outreach regarding climate change, evolution, and anthropogenic extinction. Understanding deep time is important for all these (there's even literature on that). So you'd think there would be, for instance, interactive javascript paleoglobes everywhere. But no.
The data exists (eg, https://sites.google.com/a/upr.edu/planetary-habitability-laboratory-upra/projects/visual-paleo-earth ). Doing javascript globes has gotten so easy it's used for throw-away demos (eg, http://mrdoob.github.com/three.js/examples/canvas_geometry_earth.html ). So how many more years will it be before those 1+1 get combined into a desperately needed 2? And why have several years passed already?
() There are even simpler examples of this puzzle. There aren't any good CC pictures of blood on the web. Images showing blood is a concentrated slurry of red blood cells. The need is known - the WP page has a blood smear, a three cell micrograph, and says "still looking for more good images". The consequences are known - youtube has some science misunderstanding interview videos of 'students think blood is purple, or half red and half blue' (which I can't find just now). The data exists - the folks doing blood fluid dynamics simulation have some wonderful videos and images. Mostly not online. None with an open license. Why? Well, that just didn't occur to them. And no one asks.
Perhaps it's a failure of communication? Or of vision? The lack of anyone tasked with making this stuff happen? And the default of mob sourcing it not yet being effective?
Science education content is pervasively wretched... and it's not clear why we're still letting it be so.
Mitchell N Charity
(interested in "extreme-effort" descriptive content for K-grad science and engineering education)
If the Vs get to know that map, they will locate us, and we're done!
I like to think that, from the right perspective, the path between all of these galaxies spells out a very, very rude word.
To construct the map, the standard assumption that red shift is proportional to distance was made. However, a growing body of observational evidence indicates that there are further sources of red shift not related to distance. This implies that the map must be wrong since it is based on an incomplete interpretation of red shift measurements.
For a good documentary where the mentioned growing body of evidence is being discussed by astronomers and astrophysicists see "The Universe - Cosmology Quest". A torrent can be found here for example.
or, maybe not
Table-ized A.I.
Anyone know? Are we in the centre?
The map seems to be almost empty at the equator.
I'm sure there's a logical explanation, but I've no idea what it is. Anyone care to enlighten me?
Where is the 'You are here' marker?
Caffeine combined with a lack of exercise and sunlight is lethal for your personality.
Torrent plz
That is cool, but I want webGL :)
..... no.
that map is in redshift space. did you not notice the colour-coding at the bottom is in redshift? they've not converted it to distances at all. the most they might have done is removed objects with redshifts 0.01 or 0.05 or something like that.
try and look at what's going on before you sit there banging some tired old drum.
Only 380? That's a pity. An old friend that lives 380,000,006 light years away is always inviting me over but there's no way I'd find his place without a map.
It's probably not that far as-the-crow-flies, but light takes a longer, curvy path.
Expert in software patents or patent law? Contribute to the ESP wiki!
I might suggest taking that map along if you experiment with wormhole or quantum accelerator technologies. That is only if you get lost and have any desired to return home. Then again, torch it if you think your about to be captured. After all Hawkins thinks they will be hostile when "they" get here. He also thinks there is no God. I think he suffers from "angry-cripple-syndrome" where the sufferer's point of view is tainted by his miserable existence, hence his bleak outlook.
Anyway..hows this load into my GPS?
Take the Red Pill.
You are trying to make a difference where there is none on two accounts. Firstly, taking redshift and using it as a spatial dimension for a map implies a distance interpretation or, if you wish, a uni-variate spatial interpretation of redshift. An this interpretation is obviously is wrong if, as the observational evidence indicates, there are objects with high redshift co-located with objects that have much lower redshift: the mapping is then projecting two co-located objects on different parts of the map yielding, by any commonsense definition, a wrong map.
Secondly, the redshift is proportional to distance dogma is so ingrained in astronomical teaching and literature that authors assume distance to be implied by a mere mention of a redshift measurement: the reader is supposed to know how to factor out the Hubble constant if units of distance are desired. As such, the use of redshift as a map coordinate can be assumed to have the intent to imply a spatial dimension unless explicitly mentioned otherwise.
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What you're doing is interpreting redshift as distance and then attacking that. In the science that will be done on this dataset then, yes, the cosmologists will employ a background model and convert the redshifts to "distances" (if you like) to do an analysis. Of course they will; that's what you have to do. If you want to apply your own pet model to it the data is freely available. Go ahead and knock yourself out. No-one's going to stop you.
But *that plot that they put out*, I mean *that one we're talking about* is in redshift space. What's your argument with that? They've looked at the distribution on the celestial sphere and plotted up everything with redshifts above some cut-off, whether that cut-off is z=0 or z=0.01 or wherever they put it. It's just a plot of redshifts. No assumptions made about anything.
As for this "taking redshift and using it as a spatial dimension for a map implies a distance interpretation or, if you wish, a uni-variate spatial interpretation of redshift", that's simply wrong. I can use it as a dimension if I want. I could convert it to velocities and use that quite happily -- although as you rightly point out that assumes that the entire redshift is given by a velocity. In a standard cosmology at least the vast bulk of the redshift is given by a velocity. You're free to reinterpret the data through your own model, of course. I could even sit there and examine each and every galaxy there and find the colour of it and plot that as a dimension instead. I could convert that colour to an approximate temperature and use that as a third dimension. It's you that's then interpreting that as a distance right now -- and I suspect you're doing that so you can then attack the standard model.
Good on you, the standard model is riddled with holes and I work on attacking some of those holes myself. But don't set up an immediate strawman. That plot is in redshift, and that's a perfectly valid variable to use. Furthermore, it's hte *only* variable they can use that doesn't involve any extra assumptions. As soon as you swap it to *anything else*, whether it's from your own little pet model or from standard Lambda CDM or anything else, it's model-dependent. The redshifts are what are observed, ergo that's what they've put on this plot.
I seriously don't see an issue with that.
For everything else it's pretty irrelevant to the plot, and in the press release obviously they're going to simplify down for a general audience. And as I said, you can feel free to take the raw data, or take the filtered data (where the redshifts have been calculated, doubtless using photometric redshifts which certainly contaminate the data but at a controllable rate given the sheer size of 2MASS which will beat down the statistical error), and do your own analysis. Indeed, please do. Lambda CDM is a startlingly succesful model and has beaten off anything else simply because it *FITS*, but I don't think anyone is seriously sold on it, other than it works. All of us would love something more interesting. Fewer people would love the ditching of a FLRW background entirely, chiefly because they don't have the background necessary to work with something more complicated, but there are those of us that want to drop that assumption too. But you have to be able to fit the data at least as well as Lambda CDM does otherwise you're going to be ignored just as pretty much every other alternative is ignored.
Besides, his mom told him to clean the basement.
380 million and 10, I think you'll find.
taking redshift and using it as a spatial dimension for a map implies a distance interpretation
Yes it does, but since they haven't done that all you have is a strawman.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
is all it is
Well, no, not my interpretation, theirs. Quoting:
A press release like that implies a spatial interpretation: "map", '3-D", "distance"...
That's why I emphasised "the plot we are talking about", and commented that in the press release they'd interpret it in terms of a simple model for the general public.
"But *that plot that they put out*, I mean *that one we're talking about* is in redshift space."
"in the press release obviously they're going to simplify down for a general audience"
They're going to use the standard model. And like it or fucking lump it, but the standard model interprets those redshifts as evidence for a universal expansion, which can then be converted to distances. What are they going to do, drown a press release with technical details?
The point was that *THAT PLOT THAT THEY PUT OUT* is, in contradiction to your statements "To construct the map, the standard assumption that red shift is proportional to distance was made" and "taking redshift and using it as a spatial dimension for a map implies a distance interpretation". I'm not arguing with "the redshift is proportional to distance dogma is so ingrained in astronomical teaching and literature that authors assume distance to be implied by a mere mention of a redshift measurement" necessarily; I'd say that actually the people doing this kind of work are well aware of the assumptions that underly it, but they're not often made clear to a general audience. What I'm pointing out is blindingly simple. This plot is a 2D plot with redshift information. What you choose to make of that is your own, well, choice. Don't want to interpret the redshifts as a distance measure? Go right ahead, no-one's stopping you. The press release concerned the simplest model, as it's obviously going to do, because that's the standard cosmological model.
Don't like it? Construct an alternative, fit it to data, make predictions, and do it properly. That means getting a model that fits the observed abundances of hydrogen, deuterium, tritium, helium, lithium and the like, that fits the CMB angular power spectrum, that even fits the CMB blackbody spectrum, that fits the matter power spectrum, that fits the baryon acoustic oscillations in the matter power spectrum, and fits the supernova 1a data too. And make it so that given parts of that, it can predict the rest of them, and make it uncontrived. Like it or not (and I'm not that big a fan myself), Lambda CDM isn't actually contrived -- you assume general relativity to be the theory of gravity, and then assume homogeneity and isotropy on large scales and the rest of it falls straight out. The BAOs were predicted, and their angular scale predicted, well before they were observed. The agreement is striking, even if LCDM seems to predict a slightly lower amplitude than we observe. That's not a bad thing, it's a good thing since it means we've still got things to learn. But the angular scale is there... and believe me, it's really quite hard to fit that angular scale if you play with the model much.
I don't see the "You are here" arrow.
... just in case I ever need it!
I was going to say something similar, but you beat me to it. Yeah... time, space and the speed of light are all to be figured. For all we know, none of those stars and galaxies even exist at this moment. They could have been destroyed to make way for some sort of space highway project already. (Don't forget your towel!)
In some respects, the idea of mapping the known universe is like mapping out a splash of water captured in super slow motion. It's all very interesting, but by the time you might be able to do something useful or interesting within that time and space, it will be significantly if not completely different. The way I see it, the universe is a collection of sparks in the darkness.
You know the universe is large, when things out to 380 LY away are referred to as "local"
If only we could fall into a woman's arms without falling into her hands
Space, it says is very big. I mean mind bogglingly huge...you might think it's a long way to the chemist and back but that's nothing compared to space!"
"Space it says, is very big, I mean mind bogglingly huge! You might think it's a long way to the chemist and back but that's nothing compared to space!"
Enjoy
Apocalypse Cancelled, Sorry, No Ticket Refunds
Just a wanna-be geek here that thinks 'space is so cool', but...
From the 2MASS Website itself, right on the front page:
"this all-sky map shows galaxies in the 2MASS survey color coded by their distance from us with blue showing the nearest sources, through green to the most distant sources shown in red."
Also, the first stated "Goal" on the page:
"The 2MASS Redshift Survey (2MRS) aims to map the distribution of galaxies and dark matter in the local universe, out to a mean redshift of z = 0.02 (or roughly 85 Mpc or 380 million light years)."
If they're not saying Red Shift = Distance, then what are they saying?
https://www.cfa.harvard.edu/~dfabricant/huchra/2mass/
When they interpret the map, they're going to interpret the redshift as a measure of distance. This is because they're interpreting it through the standard (big bang/Robertson-Walker) model of cosmology, which has that the universe expands. This imparts a gravitational redshift on propagating light rays -- basically the wavelength is stretched as the universe expands, which makes sense.
The analysis of the 2MASS data will be done (by the team themselves) within the bounds of Robertson-Walker cosmology. That's perfectly natural; it's the dominant model of cosmology, and it's that for a reason (it's passed most tests we've thrown at it and nothing else can actually fit all the data as well with as few parameters so of course we'll use it). Other people can get hold of all the data and run it through any other model they like -- and I'd encourage them to do so, absolutely! So long as the science isn't wonky, that's fine. For instance, I can guarantee that this data is going to be checked against models where the Earth sits near the centre of a massive void, which absolutely contradicts the first assumption of cosmology, that we're in no unique spot.
So yes, 2MASS will convert those redshifts into a distance measure. The reason they'll also have chopped off low redshifts is to avoid contaminating the data too much with galaxies where the redshift is *definitely* significantly affected by its own motion. That data will still be there, they just haven't presented it in this plot and they won't use it in the analysis. Anyone with an alternative model can keep it in if they want to.
The plot that they put out, though, is in redshift space. That means that it's not converted to distances. That was my only point -- that the plot that accompanies the press release is in redshift space and as such is as unpolluted by model-specific assumptions as possible.
(I also didn't like the bolshy nature of the original post. As a rule, anyone who posts on a forum stating something controversial as absolute truth, the way this guy did, is either trolling, a crank, or harbouring some bitterness against the establishment. Standard models are often talked about like that -- and that was one of his points that I *do* agree with; the standard model is accepted dumbly by far too many people -- but that's because they're received wisdom. The same way people are taught Mendeleven genetics even though it's a gross oversimplification and according to my dad (who's a geneticist) doesn't even work. Because it's the simple received wisdom. If you're saying something controversial and against the received wisdom you absolutely have to provide evidence to back it up... very strong evidence. I'll always be happy to recommend people take data and run it through their own model to support themselves *quantitatively*. They have to be able to explain everything LCDM can. Alas, it never actually seems to happen. And that's a big shame because there is no way on Earth or elsewhere that LCDM is the whole truth. Absolutely no way. It's a phenomenological model with parameters characterising things we don't understand which are derived from an implicit averaging process that has never been shown to work and, thus far, cannot possibly work.)
That's why I emphasised "the plot we are talking about", and commented that in the press release they'd interpret it in terms of a simple model for the general public.
But it's not just in the press release. The 2MRS website linked in the first paragraph of the article seems pretty clear....
"this all-sky map shows galaxies in the 2MASS survey color coded by their distance from us with blue showing the nearest sources, through green to the most distant sources shown in red."
And the first stated goal of the survey....
"The 2MASS Redshift Survey (2MRS) aims to map the distribution of galaxies and dark matter in the local universe, out to a mean redshift of z = 0.02 (or roughly 85 Mpc or 380 million light years)."
I feel a bit I'm talking to a brick wall here. Probably my fault getting into a more extended conversation than the original point, and not making that clear enough.
Quoting my reply to the original poster,
"The point was that *THAT PLOT THAT THEY PUT OUT* is, in contradiction to your statements "To construct the map, the standard assumption that red shift is proportional to distance was made" and "taking redshift and using it as a spatial dimension for a map implies a distance interpretation"."
That was my only point. He'd picked up on "distance" in the press release and then made some incorrect comments about the plot. Thing is that the plot they gave out is just in redshift space, which involves no assumptions, unlike when you employ a model -- the standard one or his (unquantified) alternative -- to convert those redshifts to something else. I'm sorry if I interpreted "to construct the map" in his post as meaning "to construct the map". Maybe I should have interpreted it as "When they say in the press release and on their website about distances that...", but I made the mistake of actually reading what he wrote.
Just to clarify - to construct the map, they did a large galaxy survey. They noted the right ascension and declination of each galaxy. They measured the magnitude in a variety of colours. This then lets you use what are known as "photometric redshifts" to get a reasonable approximation to the actual redshift of the galaxy. It's a phenomenological technique which is used because the prospect of finding spectroscopic redshifts on a good few hundred thousand galaxy clusters is a horrific one that would slow the survey enormously, while photometric redshifts can be found automatically. A certain sample of the redshifts are then checked against spectroscopic redshifts to test the accuracy of the algorithms. That's all you need to make this map: the redshift, the right ascension and the declination. Anything else is model dependent.
About the other point, the one that wasn't my original point but which I seem to have got involved in... Obviously the analysis will be done using a particular model, which is the standard model of cosmology, which attributes the redshift of high-redshift (z>~0.001 or so, or whatever it comes to) objects to the expansion of the universe. If they didn't do this they would have no quantitative results, so they have to use a model. To choose the model, they use the model that is currently the simplest that explains all the data so far, which is the FLRW model, involving an expanding universe. Given this expansion you will get a redshifting of the light. Given a background model -- which is judged from a compilation of this kind of data along with CMB data, the Hubble key project and possibly supernovae 1a data if you choose to include it -- you can then convert these redshifts to distance measures. This is obviously highly dependent on the model, which is dependent on all the assumptions underlying it
And there are *loads* of assumptions underlying the Robertson-Walker model, way more than things about redshifts. Indeed, it's a pretty old-fashioned approach to start deriving cosmology by looking at a Hubble diagram and redshifts -- those are predictions of it, ultimately. These days you tend to use the existence of an isotropic CMB, along with the assumption that the Earth is in no special place int he universe, to motivate the universe being homogeneous and isotropic "on average". If you then assume gravity is metric you're more or less lead to it being described on large scales by the Robertson-Walker metric. If you then assume GR you're lead to the standard model of cosmology. Is it right? No. A lot of observers may even not relise that, but I can say that with certainty. Is it the best model we've got? Yes, currently. Does anything that replaces it have to closely resemble it? Ultimately, yes, at least in observable results.
Ultimately, if someone doesn't like it, the data is publicly available for them to take and run it against their own f
That isn't needed since we're in the center of the universe. Or, more accurately, nothing is; any place you select has equal claim to that title. The picture isn't a 2D map, it's a projection of the sphere what we would see if we were in floating in empty space somewhere nearby, and could see redshift only instead of light. (Visual is actually not a good spectrum to see the sky, since most of what you see are particularly bright/hot stars relatively nearby. This doesn't give a very good picture of the structure of the universe.)
The map is 2-D, not 3-D, the redshifts are indicated only as colors, no distance conversion has been made. All galaxies observed with a positive redshift were included, most of the dots are galaxies with redshifts under 0.02. The greatest redshifts on the map are around 0.07. This is a tiny fraction of the largest observed redshifts, less than 3%, and the volume is likely to be correspondingly small compared to the volume of the universe (something like 1/50000 of the universe's volume if the redshift-distance correlation hypothesis is correct.) We are talking about a redshift map of our local galaxies, not a map of the universe.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
It's not in redshift space in the sense of a spatial dimension, the dots are just color coded on a 2-D projection. The plot appears to include all positive redshifts. Most of the redshifts are below 0.02. I don't think they are concentrating on the cosmological redshifts, rather all reasonably bright, low redshift galaxies - the point is to get the observational data, others can crunch and interpret it as desired.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
"It's not in redshift space in the sense of a spatial dimension"
that's what i've been trying to say, too... they just plotted RA vs declination and then redshift on a colour scale.