Sgr A* (galactic core)

[Cham]

There's a page about the central core of the Milky Way, which shows a movie made with Celestia. They don't give Celestia's name on the page, and I was wondering about the data they're using. Is there a way to download the STC file they made ?

http://www.mpe.mpg.de/ir/GC/index.php

[selden]

I'd suggest that you ask them.

[t00fri]

After writing a (friendly) letter of complaint to the scientist (H. Steinle) responsible for the contents of the MPE Website, about the lack of citation of Celestia, I got right away an apology and the promise for immediate correction.

Fridger

[t00fri]

This morning I got another letter with the promise to immediately add the reference to Celestia in the Website of the

Max-Planck-Institut f?r extraterrestrische Physik (MPE)
- Infrared/Submillimeter Astronomy - Galactic Center Research

along with a formal apology on behalf of the whole Galactic Center Team of the MPE for the omission.

Fridger

They will add

This animation has been created using the free space simulation
<a href="http://www.celestiaproject.net/celestia/">Celestia.

[Cham]

They added the reference. What about the data files ? I emailed the query, but didn't got any answer yet.

[t00fri]

They added the reference. What about the data files ? I emailed the query, but didn't got any answer yet.

I asked for the .stc file this morning and also gave them the reference of my analogous video (milky3.avi) that I did quite some time ago. The .stc file for all the many orbiting stars of my video is also available for download in my thread.

[That video (milky3.avi) might have to be downloaded before playing, since the resolution is pretty big]

http://forum.celestialmatters.org/viewtopic.php?t=210

I had devoted a whole thread at CelestialMatters quite some time ago to the interesting issue of a dense star cluster orbiting around the (supermassive black hole of the) galactic center (Sag A).

Fridger

[Cham]

Fridger,

did you got some news, about the data they're using (stc files...) ? I didn't received any response from my email query.

I would like to populate the galactic center with some real data (no fakes). Currently, it's pretty empty in there, in Celestia ! I defined a new black hole model at the galactic center (Sgr A*), but it's all lonely !

[t00fri]

Fridger,

did you got some news, about the data they're using (stc files...) ? I didn't received any response from my email query.

I would like to populate the galactic center with some real data (no fakes). Currently, it's pretty empty in there, in Celestia ! I defined a new black hole model at the galactic center (Sgr A*), but it's all lonely !

No, I didn't get an answer since my request for that .stc file. Apparently they confirmed over about 12 years of measurement that these innermost stars move on Keplerian orbits around the Sga A* black hole.

I recommend that .stc file of mine in the meantime

http://www.celestialmatters.org/users/t ... ns.stc.zip

It contains many more stars orbiting Sgr A*. Unfortunately, the orbits are from translating visualbins.stc rather than from 12 years of measurement

Fridger

[Cham]

I recommend that .stc file of mine in the meantime

I'm not interested in that file, since it's about fake stars (fictional).

[t00fri]

I recommend that .stc file of mine in the meantime

I'm not interested in that file, since it's about fake stars (fictional).

An attitude that I thoroughly support

Fridger

[Cham]

Here's a picture of my recent Sgr A* giant black hole that I placed at the center of the Milky Way. It needs its stars escort around him, though. I'm still waiting for the data from the previous web site. Click on the thumnail for a large version :

SgrA.jpg

[ANDREA]

Here's a picture of my recent Sgr A* giant black hole that I placed at the center of the Milky Way. It needs its stars escort around him, though. I'm still waiting for the data from the previous web site.

Martin, this project is very interesting and appreciated, I hope you'll obtain in a short time the ssc REAL data for the involved stars.
Cannot wait for the final result.
Bye

Andrea

[t00fri]

Martin,

The orbit data of the the stars within this arcsecond^3 region around the central black hole
have been published by a MPE group very recently! So what are you waiting for?

Have a look at the last few pages of:
http://arxiv.org/pdf/0810.4674v1

I'm not interested in that file, since it's about fake stars (fictional).

With a little more interest in that file which I made to illustrate the way I generated a respective .stc file for this fictional toy model, you'd be able to transform these published S-star orbits in NO time into the right frame

Fridger

[Cham]

Have a look at the last few pages of:
http://arxiv.org/pdf/0810.4674v1
...With a little more interest in that file, illustrating the way I generated a respective .stc file in my fictional case, you'd be able to transform these published S-star orbits in NO time into the right frame

Ahaa ! Thanks Fridger, I wasn't aware of that paper. The table is there :

table.gif

However, I don't know how to convert the data into a proper STC file in the way you're sugesting, without doing it by hand one star at a time.

Since you already know how to do it "in NO time", why don't you do it ?

[t00fri]

Since you already know how to do it "in NO time", why don't you do it ?

I am NOT interested in making add-ons

Fridger

[Cham]

Since you already know how to do it "in NO time", why don't you do it ?

I am NOT interested in making add-ons

Well, okay then. No galactic core for all of us in Celestia. Too bad.

[t00fri]

Since you already know how to do it "in NO time", why don't you do it ?

I am NOT interested in making add-ons

Well, okay then. No galactic core for all of us in Celestia. Too bad.

It's an easy exercise, really. While I had the original idea of displaying orbiting stars around Sgr A*, as obvious from my video

http://forum.celestialmatters.org/viewt ... 10&start=0

you found that MPE site with some real S-star measurements.

So you got to work the NON-fictional part of the project out .

Clearly all people who are not so ambitious as to using REALLY measured orbits, can take recourse to my .stc file and can visualize the qualitative features very well!


Fridger

[Cham]

Fridger,

you said you're not interested in add-ons, but then why did you made a fictional addon in the first place ? You're contradicting yourself.

Since you found the real data (I just found the web site), YOU should do the STC file, especially since you already know how to do it in NO time (from your own words).

[t00fri]

Fridger,

you said you're not interested in add-ons, but then why did you made a fictional addon in the first place ? You're contradicting yourself.

No, I am not at all contradicting myself. I merely considered my toy example to understand precisely how to parametrize orbits in remote galaxies using galactic coordinates and appropriate frame transformations via quaternions. That was the only reason.

I made several videos from the results and explained the procedure in various posts. But I would NEVER get involved with making and distributing add-ons therof. I think there are much better suited methods for displaying "cosmic structures" via appropriate classes in C++, as also Chris mentioned some time ago.
Here is his quote from the Dev list:

* New DSO type: Structure
- For spiral arms, galactic clusters, superclusters, voids, etc.
- Undecided whether this needs to be in 1.6.0

Moreover, I am busy coding more important things for Celestia right before 1.6.0 will be released.

Fridger

[Cham]

TADAAAM !

Click the thumbnails for a larger view :

sgrA0.jpg

sgrA1.jpg

Pretty close encounter :

sgrA2.jpg

Thanks a lot to Grant for the data conversion.

The black hole has a mass of about 4 Million of solar masses. The accretion disk has a 100 au radius (as stated in most papers), and its jets are aligned with the Milky Way's axis.