Galaxy colors etc.

[ElChristou]

Fridger,

I'm not asking for the release of the dsc right now, was just an idea about how to release the catalog to avoid the problem of speed on small config...
Now the 5000 first can be the nearest, the brighter, or what else, you are the specialist, you decide

Bye

[ajtribick]

I don't really have much to contribute to this, but as a suggestion to consider for the .dsc bundled with the Celestia distribution, it would be nice to have as complete a representation as possible of the Local Group, so at least we have a good representation of our galactic neighbourhood.

Not sure how that would fit in with any criteria you choose however.

[t00fri]

I don't really have much to contribute to this, but as a suggestion to consider for the .dsc bundled with the Celestia distribution, it would be nice to have as complete a representation as possible of the Local Group, so at least we have a good representation of our galactic neighbourhood.

Not sure how that would fit in with any criteria you choose however.

Cutting on DISTANCE... or redshift (z, v_rad,...)

Good idea, thanks!

Bye Fridger

PS: If anybody likes a most exotic subsample of galaxies, just let me know . E.g. if anybody cares for all those galaxies that are seen "edge-on" among the 10632 of my full catalog, NO problem. Just one Perl statement

[t00fri]

Hi all,

before going to bed, here is my little progress report as of today:

Yesterday, I displayed the dramatic increase in framerate for 10632 loaded galaxies, after Octree culling + tuning has been implemented:

25 fps ==> 88 fps,



Today, I replaced the randomized absolute magnitude (absMag) of yesterday by actual values read in from my catalog, did some further massive parameter tuning and returned to incorporate my coloration code, based on the HSV color model.

Look at the framerate I now get, again with the same 10632 galaxies loaded:

88 fps ==> 108 fps



Bye Fridger

[rthorvald]

It seems that the commercial Adobe Illustrator has the best built-in features for vectorizing images. Unfortunately, I don't have that program. The result as we need it for a template are numerical data in a file e.g. S0.pts, consisting of the 4 columns

This post is a week old, but i have been busy with other things, so i didn??t notice until now.
Anyhow, i have a (rather old) illlustrator licence i could dust off. Not quite sure what you need, but if i can help out, just PM me, and we??ll see if Illustrator 7 has the functionality you need.
(I used to work in illustrator in the nineties, but Photoshop gradually took over as the hardware got good enough to utilize it properly).

-rthorvald

[Gerbil94]

c) Globular Cluster Luminosity Function (GCLF)

d) Planetary Nebula Luminosity Function (PNLF)

e) Photometric Distances

f) Cepheid Distances

Do you have enough information in the catalogue you're using to apply the Tully-Fischer and Fundamental Plane relations to get distance?

[t00fri]

c) Globular Cluster Luminosity Function (GCLF)

d) Planetary Nebula Luminosity Function (PNLF)

e) Photometric Distances

f) Cepheid Distances

Do you have enough information in the catalogue you're using to apply the Tully-Fischer and Fundamental Plane relations to get distance?

Certainly not in one single catalog! What I do is to merge several professional, specialized catalogs together, correlate the galaxies and extract the needed distance and other information via PERL.

So I typically use 3-4 modern catalogs at once in my 25000+ galaxies *.dsc file.




I did NO data analysis using Tully-Fischer etc myself. I rather took recourse to catalogs that made use of this.

The major /quantitative/ sources of distance come

1) from measured recession velocities (corrected to the CMB frame) along with the latest (WMAP 2005) value of the Hubble constant.
I only apply this method if c*z >1000km/sec. In that case the results are quite accurate. Here the revised RC3 catalog directly tabulates the needed data and also there is the latest version of ZCAT....

2) Surface Brightness Fluctuations (SBF)
Also here I use the best available catalog. SBF distances are usually very accurate, but the analysis is somewhat tedious...

etc....

So far I did not use Cepheid data yet. Steinicke's catalog does NOT include any information on distances. On the other hand, his position data , including minor & major extensions & position angles are much more accurate than in the older revised RC3 catalog. Everything is refitted to DSS1+2 photographic data.

Bye Fridger

[Gerbil94]

Certainly not in one single catalog! What I do is to merge several professional, specialized catalogs together, correlate the galaxies and extract the needed distance and other information via PERL.

Ok, do you have enough information in the catalogues you're using to apply TF and the FP relations?

I did NO data analysis using Tully-Fischer etc myself. I rather took recourse to catalogs that made use of this.

The major /quantitative/ sources of distance come [...]

Sorry, I'm not sure I understand. Why would the distance methods you mention rely on Tully-Fisher or on the fundamental plane?

Also, what is the redshift distribution like for the objects where you were forced to apply your photometric method with fixed M_abs? Are the objects quite nearby, or do they have significant redshifts?

[t00fri]

Certainly not in one single catalog! What I do is to merge several professional, specialized catalogs together, correlate the galaxies and extract the needed distance and other information via PERL.

Ok, do you have enough information in the catalogues you're using to apply TF and the FP relations?

Let me focus on TF for the case of spirals, remembering that FP plays an analogous role for ellipticals.

If you had also communicated the purpose of your respective questions then it would have saved me some guessing what it might be...and I could have answered more specifically right away.

The straight answer is NO, since none of catalogs used contains information on the the galactic peak rotation speed (or 21cm line width) in tabulated form. I don't know about specialized respective catalogs containing >10000 - 20000 entries... I told you above that I did not enter data analysis + fitting myself.

The standard catalogs that I use certainly give the /absolute/ magnitudes in various color bands.

I did NO data analysis using Tully-Fischer etc myself. I rather took recourse to catalogs that made use of this.

The major /quantitative/ sources of distance come [...]

Sorry, I'm not sure I understand. Why would the distance methods you mention rely on Tully-Fisher or on the fundamental plane?

I just meant to say that quite a number of the the distances resulting e.g. from Hubble's law or the SBF method were cross-checked via TF in the authors' original work. In the catalog tables, this does not show up, of course.

Also, what is the redshift distribution like for the objects where you were forced to apply your photometric method with fixed M_abs? Are the objects quite nearby, or do they have significant redshifts?

Again, here it would be good to know what is in your mind behind the question!

I actually plotted & studied many distributions with my extracted galaxy data. We know fom the rather complete SDSS survey for example that the number distribution of the redshift z rises strongly from z=0 until z~0.1 where it peaks. The RC3 sample of 25000+ galaxies (that I use) peaks earlier around z~0.05, presumably due to an inherent magnitude bias.

My "universal M_abs" method always comes in as a "last resort" in all cases where no other distance information is given in the used catalogs. The data on recession velocities are rather complete at the larger redshift end of the RC3 catalog. Most of the "M_abs" applications refer to v<1000km/sec in the cases where SBF data are lacking.

Anyhow my catalog lists the distance method used in ALL cases in form of a comment, along with further parameters not yet exploited by Celestia.

Bye Fridger

[Gerbil94]

The straight answer is NO, since none of catalogs used contains information on the the galactic peak rotation speed (or 21cm line width) in tabulated form. I don't know about specialized respective catalogs containing >10000 - 20000 entries...

Ok, that's unlucky. But you really only need velocity dispersions for the ones that don't have any SBF or Hubble distance measurements. How many of those are there?

The standard catalogs that I use certainly give the /absolute/ magnitudes in various color bands.

Right, based on the distances they compute with the SBF/other methods?

I just meant to say that quite a number of the the distances resulting e.g. from Hubble's law or the SBF method were cross-checked via TF in the authors' original work. In the catalog tables, this does not show up, of course.

Ah, I understand.

Again, here it would be good to know what is in your mind behind the question!

Well, as you've shown, there's (very) roughly a 1.5-2 mag spread in absolute magnitudes for particular galaxy types. The TF relation and the FP give you a potential opportunity to account for that scatter to better than a magnitude for those galaxies that are without both SBF and Hubble distances. Using the FP and TF relations instead of assuming a fixed absolute magnitude could substantially reduce the probable error in the distance estimates made photometrically.

My "universal M_abs" method always comes in as a "last resort" in all cases where no other distance information is given in the used catalogs. The data on recession velocities are rather complete at the larger redshift end of the RC3 catalog. Most of the "M_abs" applications refer to v<1000km/sec in the cases where SBF data are lacking.

Good. I was wondering whether there'd be any complications in applying the TF and FP due to high redshifts (luminosity distance vs. Hubble distance, evolution, etc).

Anyhow my catalog lists the distance method used in ALL cases in form of a comment, along with further parameters not yet exploited by Celestia.

Excellent. I await your catalogue with interest

[t00fri]

The straight answer is NO, since none of catalogs used contains information on the the galactic peak rotation speed (or 21cm line width) in tabulated form. I don't know about specialized respective catalogs containing >10000 - 20000 entries...

Ok, that's unlucky. But you really only need velocity dispersions for the ones that don't have any SBF or Hubble distance measurements. How many of those are there?

Unfortunately, still several thousand among 10632 in Steinicke's NGC/IC catalog. That depends on the threshold I put in the recession speed for using Hubble's law. If I go below 1000 km/sec the number decreases significantly.

One check option might be another "naive" (but sometimes popular) universality ansatz, namely that (classes of) galaxies have a universal size like 25kpc or so. Then the distance follows trivially from the observation of the galaxy's angular extension and that number
It might be worth just comparing the spread among these two naive methods...

Well, as you've shown, there's (very) roughly a 1.5-2 mag spread in absolute magnitudes for particular galaxy types. The TF relation and the FP give you a potential opportunity to account for that scatter to better than a magnitude for those galaxies that are without both SBF and Hubble distances. Using the FP and TF relations instead of assuming a fixed absolute magnitude could substantially reduce the probable error in the distance estimates made photometrically.

Certainly, that's of course just the content of TF: absMag versus eta=c1*log V +c2, with V being the peak rotation speed.

Unfortunately, given our ambitious task of rendering 10000+ galaxies , "handycraft" is clearly out and we should have rather complete /very big/ catalogs about rotation speeds for making use of TF...

With Perl its quite easy to incorporate further info from other catalogs at any time. So perhaps new sources come to mind in the near furture...

Bye Fridger

[t00fri]

Hi Gerbil94,

thanks again for your initial questions about the Tully-Fischer relation etc. Our respective discussion got me back searching for missed catalog resources, and indeed I had overlooked an extensive and very sophisticated "classical" analysis based on TF for spirals and Dn- ?? for ellipticals, altogether ~3500 distances for galaxies that typically have recession velocities <4000 km/sec. That's just the region where I badly need further distance info.

So, I am in the process of incorporating these new 3500 distances into my Celestia catalog by means of Perl. I expect that now the number galaxies with badly known distance is getting pleasantly small!

As you can infer from the table below the TF relation is typically exploited for the H and I bands, where the TF correlation is known to be tightest...

Bye Fridger


JEFFREY A. WILLICK et al. 1997
http://cdsaas.u-strasbg.fr:2001/ApJ/journal/issues/ApJS/v109n2/34879/34879.pdf

The ultimate goal was to construct a homogeneous database of redshift-independent distance estimates. This work brought together a disparate set of six spiral galaxy samples for which distance estimates are obtained using the Tully-Fischer (TF) relation. The main properties of these six spiral samples are summarized in Table 1

Code: Select all

Sample   Photometric Method  Spectroscopic Method    Number  Notes
===================================================================
HMCL . . . CCD I-band        H I profile widths        428     1
W91CL . . .CCD r-band        H I profile widths        156     2
W91PP . . .CCD r-band        H I profile widths        326     3
CF . . . . CCD r-band        Optical rotation curves   321     4
MAT . . . .CCD I-band        H I + optical            1355     5
A82 . Photoel. H-band        H I profile widths        359     6
===================================================================
                                                      2945
Table1:

elliptical galaxy sample :   (Dn- ??)                   544
====================================================================
                                                      3489


Note that the elliptical data have also been matched to the spiral data!
Most are based on H I velocity widths, while one (CF) uses exclusively
optical rotation curves and one (MAT) a mixture of both H I and optical widths.
Furthermore, the various samples typically probe different regions of the sky.
To this already disparate group of spiral samples, a sample of elliptical
galaxies, whose distances are estimated using the Dn- ?? relation.

[symaski62]

http://cvs.sourceforge.net/viewcvs.py/c ... te#dirlist

t00fri WTF ! galaxy

celestia 1.4.0 pre 6 ?!? => galaxy black .

celestia 1.4.0 pre 7 => galaxy color !

[selden]

What symaski62 is trying to say in his obscure brevity is that Chris' most recent Celestia checkin is still incomplete.

In particular, galaxy rendering under Windows doesn't work when Celestia is built from the current CVS archive. (I deleted all previously compiled libraries just to make sure it was built completely from scratch.)

As of the morning of July 16th, both Galaxies and Nebulas are not drawn. Toggling the menu option Render/View Options/show galaxies does nothing. Typing "u" multiple times does nothing. Typing ( and ) (the new galaxy visual magnitude adjustments) do nothing.

We just have to hope Chris doesn't fall off a cliff while climbing...

[t00fri]

What symaski62 is trying to say in his obscure brevity is that Chris' most recent Celestia checkin is still incomplete.

In particular, galaxy rendering under Windows doesn't work when Celestia is built from the current CVS archive. (I deleted all previously compiled libraries just to make sure it was built completely from scratch.)

As of the morning of July 16th, both Galaxies and Nebulas are not drawn. Toggling the menu option Render/View Options/show galaxies does nothing. Typing "u" multiple times does nothing. Typing ( and ) (the new galaxy visual magnitude adjustments) do nothing.

We just have to hope Chris doesn't fall off a cliff while climbing...

Selden,

that code works fine for me both if compiled under Linux and Windows.

Two crucial things to remember:

a) That code is about the earliest version of the galaxy patch and much is still to come. You will only see rendered elliptical galaxies if you dont read in the template images for the seven spiral Hubble classes: S0.pts, Sa.pts,Sb.pts,Sc.pts,SBa.pts,SBb.pts,SBc.pts.
These templates should be in the same dir as celestia.cfg.
If people don't have them I'll try to upload them.

b) Chris moved the brightness keys from CTRL+u, CTRL+R to ( and ). But note (I discussed that in the developers list!) I think the functions are interchanged mnemonically!

c) The galaxy color is still a horrible pink, that I have also eliminated immediately

I shall be in much reduced online state during the next 3 weeks...

Bye Fridger

[danielj]

But this is not a direct link.It is a link for the general directory of Celestia sourceforge.From which folder I have to download?

http://cvs.sourceforge.net/viewcvs.py/celestia/celestia/?sortby=date#dirlist

t00fri WTF ! galaxy

celestia 1.4.0 pre 6 ?!? => galaxy black .

celestia 1.4.0 pre 7 => galaxy color !

[selden]

The new galaxy database requires the new Celestia code. You have to download it all and compile from scratch. But, despite it working for Fridger, it still doesn't work for me, so don't waste your time on it just yet.

[t00fri]

Selden,

I am confused. Here is a step by step instruction:

1) Compile the latest CVS code.
2) Download the templates from

http://www.shatters.net/~t00fri/images/STemplates.zip

3) unpack them in the same directory where celestia.cfg is located.

4) start celestia
5) type ENTER
6) type m 31
7) type c
8.) push ( until you see the Andromeda galaxy.
9) you should also see an elliptical galaxy lower down...

It's all that simple. The pink color is horrible.

You may do the same with e.g. all 43 Messier galaxies and convince yourself that they are all correctly alligned

Bye Fridger

[t00fri]

Just a little later...

there seems indeed something fishy under XP with the galaxy display. Some are correctly displayed but some are NOT.
Looking into that ...Toti has just complained that the CVS update is not working well. Patches are not updated as they should... That could be the reason?


For sure, under Linux everything is fine.

[selden]

Fridger,

There always has been a problem with recompiling under Windows, especially when .h files are updated. It's like nmake isn't finding all the dependencies. I deleted everything in /src/ so that CVS downloaded a fresh copy of all of the source code and thus forced makerelease.bat to recompile everything.

After installing your prototypes and turning the galaxy limiting magnitude way up, I now can see many of your galaxies. As you say, they're an ugly pink
[edit] I can see M110 and M32 but not M31. Apparently spirals are broken. [/edit]

However, it's clear that a lot of Windows user-interface code hasn't been written yet. For example, I'm getting no on-screen text display showing the change in limiting magnitude for galaxies when I type either ( or ) I think there ought to be a text display like there is for the change in limiting magnitude of stars.

Much more important to me, however, no Nebula objects are being drawn at all, no matter how long I hold down ( [shift 9]. My understanding is that now they're selected separately from galaxies, but there is no "show Nebula" option in the Render/View Options menu.

[edit] Searching the source code, I found that ^ toggles Nebula drawing. They're being drawn now. *whew* However, there doesn't seem to be any magnitude control for them. Hopefully that'll be added in the not too distant future.[/edit]