And you can see the new version of the paper here: arxiv.org/abs/2412.08327 🔭

This may be of interest for @clarakm.bsky.social @zacksavitsky.bsky.social @monisharavis.bsky.social
@jtimmer.bsky.social @nebulousnikki.bsky.social @markzastrow.com @chrislintott.bsky.social

bsky.app/profile/alum...

Regarding the Ghost Planetary Nebula hypothesis:

We don't think the velocities we measure in the gas agree with it. The turbulence (width of the emission lines) is also, we think, too low to be caused by shocks in the gas.

So...more research is needed to know for sure why is this nebula shining! 🔭

In addition, with the @gtctelescope.bsky.social (largest optical telescope in the world!) we get spectra and measure the velocity of the nebula. It's moving at ~20 km/s toward us, while Andromeda is coming at ~300 km/s!

These two evidences show that the nebula is located within the Milky Way. 🔭

We used the JAST80 from @cefca-oaj.bsky.social in Teruel (Spain), with a large field of view, to observe less ionized oxygen ([OII], white contours).

We see it separated from [O III], in layers. These structures are too small to be resolved in distant nebula, but easy to see in Milky Way objects. 🔭

Here is our press release: www.cefca.es/news/show/339

To sum up: Observing with two telescopes (GTC and JAST80) we confirm that SDSO-1 is in the Milky Way, but we don't think that its origin is clear yet.

We believe that the "Ghost Planetary Nebula" hypothesis doesn't agree with our data. 🔭

Hi! I am Alejandro Lumbreras-Calle, I am postdoctoral researcher in Astrophysics, and I would like to join the Science feed. Here is my ORCID orcid.org/0000-0002-66...

And, as @darksapiens.bsky.social points out, the velocity we measure doesn't quite match with the hypothesis presented in this new paper.

Even before us, others published different results (arxiv.org/abs/2303.09425 and arxiv.org/abs/2307.06308).

I think the nebula still remains (a bit) mysterious!

We actually have more evidence supporting that the nebula lies within the Milky Way: For example, the separated [O II] emission we detect with our telescope 🔭 at @cefca-oaj.bsky.social.

You can read a bit more about it in the thread I wrote when we presented the paper: bsky.app/profile/alum...

Great picture! In fact, we already showed last December that this nebula was in the Milky Way, not in Andromeda. Here is the paper: arxiv.org/abs/2412.08327

And here is a thread explaining it:
bsky.app/profile/alum...

It is "slightly" sped up: Roughly one hour from the first to the last frame

Hi! I am the first author of the paper, thank you for sharing!

We used also a telescope from the OAJ (Teruel, Spain). And we are not sure of what it is exactly, but it does seem to be in the Milky Way.

For more info, the paper arxiv.org/abs/2412.08327 and my thread 👇
bsky.app/profile/alum...

Finally, I want to thank all the co-authors and the telescope🔭 operators! Also, thanks to the discoverers of the nebula (Strottner, Dreschler, and Sainty), and thanks to Bray Falls, whose tweet about the discovery I saw and pushed me to start this project!