What is this green colored thingy?

[Nightwatch]

 



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

[fluffyporcupine]

apart from a pea for hanny? the spectrum suggests something to do with star formation to me. sorry not much help

[Arralen]

It's not a quasar .. spectrum lines are not broad enough:
http://www.sdss.org/gallery/gal_zqso.html

Looks rather odd to me - its a bit away from us (z=0.2817) and rather small, yet it must be quite bright, as the signal/noise ration of the spectrum is exceptional. And yet no QSO, AGN or somesuch ?!

[fluffyporcupine]

And yet no QSO, AGN or somesuch ?!

dont AGNs usually have broad spectrum too? well, i think seyfert 1s do anyways, not sure about sy2

[Rick Nowell]

There's an article here about green stars that mentions this at the end.

"Old novae in the "nebular" phase often look green.  This is because
they are surrounded by a shell of gas that emits spectral lines of
doubly ionized oxygen (among other things).  Although these object
certainly look like green stars in a telescope---the gas shell cannot
usually be resolved---the color isn't coming from a stellar
photosphere."

http://www.faqs.org/faqs/astronomy/faq/part7/section-7.html

Maybe that helps..

[fluffyporcupine]

well the spectrum suggests a lot of doubly ionised oxygen! i guess thats where the colour comes from then!

[Rick Nowell]

I wouldn't know where to look for doubly ionised oxygen in a spectrum. In fact i don't know what the
aforementioned is at all. A galaxy surrounded by ionising oygen is not something i've heard of- is there
a name for such an object? It would be have to be very energetic to do the ionising bit.

[fluffyporcupine]

I wouldn't know where to look for doubly ionised oxygen in a spectrum. In fact i don't know what the
aforementioned is at all. A galaxy surrounded by ionising oygen is not something i've heard of- is there
a name for such an object? It would be have to be very energetic to do the ionising bit.

its marked as OIII on the spectrum (OI is neutral, OII ionised if i remember correctly) I dont think its so much that the galaxy is surrounded by it but producing it at a prodigeous rate (IMHAO of course)

[Hanny]

apart from a pea for hanny? the spectrum suggests something to do with star formation to me. sorry not much help

Just from reading the topic title I thought there was a post in it like this
I actually have no idea 'bout most of the peas either.. guess they're just to fuzzy... 

[Rick Nowell]

Quasars that are surrounded by ionised gases are studied for Lyman-alpha whatevers. It is
thought Dark Matter Halos may be a cause. Interesting article about such happenings around
a quasar.     http://www.phys.au.dk/~michaelw/naturepr2004en.html

I guess it's not too much of a jump to suggest that this is a galaxy surrounded by an ionising
dark matter halo which is causing gases around the galaxy to becoming extremely energetic.

In which case, get onto the Dark Matter people and tell them what you've found.

 

[zookeeperKevin]

The fact that the image is green comes from the fact that the powerful [OIII] line sits in the r-band (which is the green in RGB). Whatever it is it has extremely powerful emission lines, but the ratios look very weird to me. It's definitely a strange object. I will have a more detailed look at it in the office tomorrow.

[Hanny]

The fact that the image is green comes from the fact that the powerful [OIII] line sits in the r-band (which is the green in RGB). Whatever it is it has extremely powerful emission lines, but the ratios look very weird to me. It's definitely a strange object. I will have a more detailed look at it in the office tomorrow.

And is it just this one or does that count for more of the peas?

[zookeeperKevin]

I had a look at some of them and it seems so, yes. Peas are galaxies with enormously powerful emission lines.

[Alice]

Peas are galaxies with enormously powerful emission lines.

That's BRILLIANT. 

[Hanny]

You guys make me laugh! Thanks for the answer Kevin, that is brilliant! And Rick, I started that topic as a joke!