Give peas a chance!

[Hanny]

yeah, you deserved it! So... now I can throw it in the soup huh

[starry nite]

Just let me kiss it goodbye first. I've grown very attached!

[Arralen]

Wait ! Wait !!
Before you through it into the soup .. look, it's a quite peculiar pea:

Not only the Haplpha emission line has a broad base - all of them have .. what means all that gas and dust is whirling around in circles quite fast .. a really massive AGN ?! Multiple BH ?!

[starry nite]

So you're saying it's a swirling cauldron of pea soup? A tempest in a pea-pot? Should I visualize whirled peas?
                                           (To Galaxyzoo members whose English is not great, these are bad jokes.)

[Alice]

I hope nobody is thinking about giving up peas for Lent-il . . . .

[Hanny]

So you're saying it's a swirling cauldron of pea soup? A tempest in a pea-pot? Should I visualize whirled peas?
                                           (To Galaxyzoo members whose English is not great, these are bad jokes.)

Heh heh, thanks for the subtitles

[weirdWendy]

my greenest pea yet:
http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587728917372993708

[starry nite]

Hi wlindboe,
Sad to say that pea has been posted before. (http://www.galaxyzooforum.org/index.php?topic=3638.msg88776#msg88776)
s.n.

[weirdWendy]

Hi wlindboe,
Sad to say that pea has been posted before. (http://www.galaxyzooforum.org/index.php?topic=3638.msg88776#msg88776)
s.n.

drat!  i thought i had searched for the little bugger and come up empty.  must have been searching in the wrong category.

back to the pod...

[diaswa]

A Blue Pea ?

Spectra shows strong O III - O II features.

http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587724648181923856

[starry nite]

Purple pea! z=0.4115, just above the 0.348 Rick Nowell lists as the upper end. Interesting how it goes from vivid green to purple over a small change in z-shift range.

ra=168.08022268, dec=63.53022563, ObjId = 587729154132148690
http://cas.sdss.org/astro/en/tools/explore/obj.asp?id=587729154132148690

[Galaxy Hunters Inc]

Purple pea! z=0.4115, just above the 0.348 Rick Nowell lists as the upper end. Interesting how it goes from vivid green to purple over a small change in z-shift range.

Hey Starry, you are on fire! two peas in three days. Well done. That soup is starting to look pretty good. So good in fact it should apPEASe (Did I Have To) any hungry feelings you get from working so hard..........um. I know.......Lame, lame, lame.LOL
I hope the guys in the know extract all the useful and hard won info we all try and find.

[starry nite]

Thanks, Galaxy Hunters Inc.
Now, to prove that I'm not obsessed with them, a list of all the Peas with spectral charts arranged by z-shift:

[Edit: moved the list here: http://www.galaxyzooforum.org/index.php?topic=3638.msg108116#msg108116]

Characteristics of a "Pea" galaxy A.K.A. OIII galaxy:
1. Mostly-flat spectral chart except for:
2. An extreme peak at OIII (double-ionized oxygen emission line),
3. If there is a peak at OII, it must be shorter than the OIII peak,
4. Other peaks must all be smaller than the OIII.
5. Any H-peaks should be narrow, not wide-based which might indicate a quasar (with a redshift z<0.3).
6. Redshift range (z) of approximately 0.14 - 0.35 for a green color on SDSS.

[Rick Nowell]

A lot of effort must have gone into your posting. A worthwhile achievement indeed. The question of
colours and ionised substances is a complex one. The deep 'emerald' green classic Pea Galaxies do
seem to be distributed within a narrow redshift range, whilst others displaying classic [OIII] spectral
lines seem to have different colours depending on the redshift range- maybe.

There is a posting that discusses the blue and green colour variations, which is useful.
http://www.galaxyzooforum.org/index.php?topic=9641.0.

It doesn't explain why there are [OIII] galaxies that are purple or pink - maybe they have a different
set of ionised elements there as well. I guess it becomes whether we wish to find objects with [OIII]
peaks only, or ones that are green, blue etc. Of course there are many other highly-ionised objects
that have different peaks- hydrogen alpha seems to be a popular one. Indeed only y'day in Alice's
OOTD posting http://www.galaxyzooforum.org/index.php?topic=10017.0 there is a spectrum that
has highly ionised Hydrogen. http://en.wikipedia.org/wiki/Hydrogen_alpha

Maybe in GZ2, there could be a sticky for objects with a spectrum showing extreme peaks. The thing
is that objects further away have an increased 'noise floor', which could obscure anything extreme.
Also, as objects are further, peaks get redshifted etc.

Reply#10 in topic 9641 by Eigenstate includes a link to one of his papers on [OIII] transitions.
http://www.jyi.org/volumes/volume7/issue1/articles/bachilla.html

All of which gets away from Hanny's original Pea thread, which is any object that is green!

[starry nite]

Thanks, I hadn't seen those threads. I notice Alice's purple pea (your first link) is at z=0.0933. This falls between the blue one at 0.0247, and the pinks at 0.0998 and 0.1066. Purple is sort of between blue and pink, so that seems to make sense. There don't seem to be many things with the Pea spectral chart that aren't green; I'd suggest that we post them here to be tidy and because if we were further away, they'd look like green Peas. I'd be interested to see the transitional color between the purple and the emerald, and then back again somewhere after 0.35. Is it gray? Brown? Plaid?