![[OIII] cloud near Andromeda (M31) | by gjdonatiello](http://live.staticflickr.com/65535/52617366848_6f81e9db66.jpg)
gjdonatiello
[OIII] cloud near Andromeda (M31)
[OIII] cloud near Andromeda (M31)
Credit: Giuseppe Donatiello
A few people, knowing of my ultra-deep images of M31, are asking me if I also captured the [OIII] cloud recently announced by Marcel Drechsler et al. with a letter published in ASS RN and some opinions about it.
Yes, for some years already but not recognized as an ionized oxygen cloud because I don't do narrowband captures (except for some in H-alpha) because I'm primarily interested in the stellar component of the system: I'm looking for stellar streams and dwarf galaxies, not nebulae.
The excess green/cyan is present in almost all my color images (see link below) and often desaturated as well. I have always thought that this excess was attributable to the scattering of cirrus clouds of galactic dust and, in any case, I was not equipped to take shots in [OIII]. So my congratulations to the discoverers on their new find of extremely faint clouds, albeit announced in a non-peer-reviewed publication.
- What do you think about it?
That something is projected onto another object does not imply correlation and would not be the first case. The [OIII] emission is typical of planetary nebulae, therefore of stellar evolution, therefore I am inclined towards a local cloud.
The very sharp appearance of the streaks is another indication of proximity since small instruments do not achieve that degree of resolution on sources at the distance of M31. Nevertheless in my images it is seen, together with other very weak structures in the Andromeda halo (which however I do not see in the images published by the authors).
If radial velocity measurements validated a distance of about 750 kpc, compatible with that of M31, a truly intriguing scenario would open up and would be a very remarkable discovery, otherwise a mere astrophotographic curiosity.
Original Version: flic.kr/p/2h6c3Dm
Related images:
[OIII] cloud near Andromeda (M31)
[OIII] cloud near Andromeda (M31)
Credit: Giuseppe Donatiello
A few people, knowing of my ultra-deep images of M31, are asking me if I also captured the [OIII] cloud recently announced by Marcel Drechsler et al. with a letter published in ASS RN and some opinions about it.
Yes, for some years already but not recognized as an ionized oxygen cloud because I don't do narrowband captures (except for some in H-alpha) because I'm primarily interested in the stellar component of the system: I'm looking for stellar streams and dwarf galaxies, not nebulae.
The excess green/cyan is present in almost all my color images (see link below) and often desaturated as well. I have always thought that this excess was attributable to the scattering of cirrus clouds of galactic dust and, in any case, I was not equipped to take shots in [OIII]. So my congratulations to the discoverers on their new find of extremely faint clouds, albeit announced in a non-peer-reviewed publication.
- What do you think about it?
That something is projected onto another object does not imply correlation and would not be the first case. The [OIII] emission is typical of planetary nebulae, therefore of stellar evolution, therefore I am inclined towards a local cloud.
The very sharp appearance of the streaks is another indication of proximity since small instruments do not achieve that degree of resolution on sources at the distance of M31. Nevertheless in my images it is seen, together with other very weak structures in the Andromeda halo (which however I do not see in the images published by the authors).
If radial velocity measurements validated a distance of about 750 kpc, compatible with that of M31, a truly intriguing scenario would open up and would be a very remarkable discovery, otherwise a mere astrophotographic curiosity.
Original Version: flic.kr/p/2h6c3Dm
Related images: