Author Topic: Has anyone made a Milky Way rendering using Gaia data?  (Read 1009 times)

Offline DrRobin

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Out front of our house hangs the iconic Earth flag, based on the famous Apollo-era image. I have thought it would be cool to buy another that shows a galaxy image. I would've thought that this would be already out there, but my searches haven't found anything good. Now that the first data release from the Gaia mission has been out for a while, it seems like an obvious idea to try to reconstruct an image of what our own Galaxy would look like from the outside, analogous to the telescopic images of the Andromeda galaxy. Looking around on the Gaia Mission homepage, they do have some nice outreach visuals, but as far as I can find, not just a pretty Milky Way selfie, suitable for printing on a flag, t-shirt, etc. I was going to ask them directly, but I thought first I would ask here if anyone knows someone who has done this already. Thanks!

Online AncientU

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Re: Has anyone made a Milky Way rendering using Gaia data?
« Reply #1 on: 11/16/2017 12:58 PM »
Out front of our house hangs the iconic Earth flag, based on the famous Apollo-era image. I have thought it would be cool to buy another that shows a galaxy image. I would've thought that this would be already out there, but my searches haven't found anything good. Now that the first data release from the Gaia mission has been out for a while, it seems like an obvious idea to try to reconstruct an image of what our own Galaxy would look like from the outside, analogous to the telescopic images of the Andromeda galaxy. Looking around on the Gaia Mission homepage, they do have some nice outreach visuals, but as far as I can find, not just a pretty Milky Way selfie, suitable for printing on a flag, t-shirt, etc. I was going to ask them directly, but I thought first I would ask here if anyone knows someone who has done this already. Thanks!

Neither Gaia or any existing experiments have the capability to do a Galactic 'selfie' -- it has little ability to penetrate the Galactic disk and bulge because of dense molecular clouds, thus missing most of the 'interesting' or characteristic structure.  The best bet is to get Hubble images of external galaxies that are thought to resemble our own and add a little You are here arrow.
« Last Edit: 11/16/2017 12:59 PM by AncientU »
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Offline speedevil

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Re: Has anyone made a Milky Way rendering using Gaia data?
« Reply #2 on: 11/16/2017 05:01 PM »
Neither Gaia or any existing experiments have the capability to do a Galactic 'selfie' -- it has little ability to penetrate the Galactic disk and bulge because of dense molecular clouds, thus missing most of the 'interesting' or characteristic structure.  The best bet is to get Hubble images of external galaxies that are thought to resemble our own and add a little You are here arrow.
Selfie is perhaps the ideal term for what GAIA data can do.
A sort-of-representative shot, taken at an odd angle often with heavy use of photoshop or other filters.
Combined with recent better understandings of more distant galaxies and galactic evolution, a reasonable stab at an accurate selfie (by selfie standards) might be doable by the time the full GAIA dataset comes in.

Offline AegeanBlue

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Re: Has anyone made a Milky Way rendering using Gaia data?
« Reply #3 on: 11/16/2017 05:10 PM »
My understanding about the Gaia catalog is that it will produce a map of the Milky Way that will look like a terrestrial lidar scan of a forest rather than a selfie per se. The lidar sends out pulses that reflect from all trees in the line of sight. However when in the software (in class we used Merrick MARS) you pan and change perspective to aerial view, you see the gaps in the forest coverage formed behind the nearest trunks, you do not have a full scan of the forest. Still, I too would like to see a visualization where someone has taken the 3D positions of the star in the Galaxy, turned the viewpoint 90 degrees and zoomed out to Galaxy level so we can see the distances of all points in the catalog. All that has so far been are either from the viewpoint of earth or an artist rendering of the Milky Way with a small circle for HIPARCOS and a larger circle for Gaia stars. If anyone ever does a pan and zoom out of the Milky Way, the ESA Gaia twitter feed is where you will see it:

https://twitter.com/esagaia?lang=el

Online hop

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Re: Has anyone made a Milky Way rendering using Gaia data?
« Reply #4 on: 11/19/2017 09:01 PM »
Combined with recent better understandings of more distant galaxies and galactic evolution, a reasonable stab at an accurate selfie (by selfie standards) might be doable by the time the full GAIA dataset comes in.
Keep in mind Gaia will map only ~1 billion stars. The milky way has ~200-400 billion stars, so even the final data release won't give anything close to a full 3d model that you could construct an outside view from.

Offline DrRobin

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Re: Has anyone made a Milky Way rendering using Gaia data?
« Reply #5 on: 11/19/2017 11:49 PM »
Combined with recent better understandings of more distant galaxies and galactic evolution, a reasonable stab at an accurate selfie (by selfie standards) might be doable by the time the full GAIA dataset comes in.
Keep in mind Gaia will map only ~1 billion stars. The milky way has ~200-400 billion stars, so even the final data release won't give anything close to a full 3d model that you could construct an outside view from.

Right, but in my original post I set out much more modest goals: A good enough reconstructed image from the data to make a flag analogous to the iconic Earth flag (that hangs in front of my house now). Part of what started me thinking down this path has been the (to me) surprising controversy over the past decade regarding the basic number and structure of the arms of our own galaxy. I had naively thought that was long worked out. I think it should be possible (and of interest) to combine Gaia data with what is already known from radio astronomy to make "a reasonable stab" at this.

A meta-point (probably preaching mostly to the choir here) is not to underestimate the emotional and psychological importance of these sorts of images, beyond their scientific value to researchers in the field. Carolyn Porco, imaging team leader for Cassini (we overlapped at Caltech back in the late 70's -her thesis advisor was my student house RA) has been making this argument for years (likewise for the Hubble team). I think a "you are here" image of our own Galaxy might have some value on this axis.

Offline as58

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Re: Has anyone made a Milky Way rendering using Gaia data?
« Reply #6 on: 11/20/2017 04:24 PM »
As AncientU wrote, the big problem is that Gaia, or any telescope operating at optical wavelengths, can't see through dust clouds. Especially towards the inner Milky Way there's a lot of stuff in the way. Though even in the absence of dust Gaia's survey probably wouldn't go deep enough and the parallaxes wouldn't be accurate enough to get a good 3-D image of the whole Milky Way.

There are some plans of doing an astrometry mission like Gaia in the infrared, where dust extinction is much smaller, but I don't think IR telescope/detector technology is mature enough at this point.   

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