Large, diffuse galaxy of young stars? What is this?

What is this? It seems like a fairly large, diffuse galaxy full of young, blue stars. Or is it a nebula? I can’t tell. It didn’t register an NGC catalog entry that I could see.

Oooooh, that is awesome! Is there any chance it could be two diffuse galaxies? If it’s one, then the slightly S shape is very odd. Either way, beautiful find! I will point our team at this!


Thanks for saying so :slight_smile:

It sure could be 2 distinct galaxies. There does appear to be slight separation where I"d expect the core to be. There’s an intense region of star forming activity on the “right” as this picture is oriented.

You know, on second look, I’m not sure the S shape is so slight. I think it may be a 2-armed spiral seen almost edge-on, perhaps the “bottom” arm moving away from us and the star forming one moving toward. Perhaps there’s red-shift data somewhere that would tell the story.


Here are some replies from my colleagues (I emailed this one around):

Stephanie Juneau (NOAO) said

I wonder if it’s a tail of the blue fluffy part centered here:
Also, one of the star-forming knots has an SDSS spectrum with emission lines,
and a spec-z of 0.0017 (equivalent to ~500km/s or a D_L of 7Mpc), so it
would be extragalactic but nearby.

It reminds me of galaxies undergoing gas stripping such as this one:

In any case, a great and beautiful find!

Arjun Dey (NOAO) said,

Yes- this is gorgeous. I agree that it looks like an interacting system
with stars and gas stripped out of the star-forming lump in the north.
The scale is not huge, though - looks like ~200”. If the redshft is
right, this is about 7 kpc, end-to-end.

If you turn on the “SDSS Spectra” overlay layer, you’ll see that there are spectra of some of the small background objects nearby, and one of the blue blobs probably within that galaxy – at redshift 0.0017 (labelled “Galaxy z=0.002”).