The one that got away ...

[wimvb]

... or at least is about to get away.

The centre of the image is supposed to show Andromeda XXX, a satellite galaxy to the Andromeda galaxy (M 31). Both SIMBAD and Wikipedia agree as to its position.

The only other information I can find on it is here:

https://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/community/nearby/

(Btw, don't Google Andromeda XXX without parental guidance 😉 )

The BIG question is:

Should I continue to collect data on this object, or not? What do you think?

(this is 40 minutes L so far)

 

Edited October 3, 2022 by wimvb

[ONIKKINEN]

I wonder if the coordinates are marked correctly, none of the sky surveys and catalogues i checked seem to have anything in the area. There is some IFN visible a bit of a ways off to the side in some of the surveys so its reasonable to think that the exposures are deep.

Maybe sacrifice a couple of hours for curiosity? Doubt there are many if any images of the thing really so could be interesting.

[wimvb]

1 hour ago, ONIKKINEN said:

I wonder if the coordinates are marked correctly, none of the sky surveys and catalogues i checked seem to have anything in the area. There is some IFN visible a bit of a ways off to the side in some of the surveys so its reasonable to think that the exposures are deep.

Maybe sacrifice a couple of hours for curiosity? Doubt there are many if any images of the thing really so could be interesting.

I checked and double checked. There are a few articles on spectormetric studies of Andromeda dwarf satellite galaxies. Apparently this one was discoverd ca 2012. It seems to have been identified as a dwarf spheroidal galaxy through the study of 8 (!) of its stars, none of which are visible in this image.

Here's a deeper image with 2.25 hrs of integration time. This is luminance only with just a basic stretch applied. Clouds moved in after I collected this data and 30 minutes with a red filter. There's definitely some ifn coming through on the right hand side.

Edited October 3, 2022 by wimvb

[wimvb]

A fellow amateur astronomer on a Swedish FB group pointed me to this scientific publication, showing all known structures of the M 31 group, including dwarf galaxies and tidal streams.

https://arxiv.org/abs/1810.08234

Figure 12 in this publication is particularly interesting

Interestingly enough, the image does show a tidal stream near ngc 147, which so far has eluded amateur astrophotographers. Unfortunately, this stream looks too wide for the fov of my telescope.

 

[symmetal]

Thanks for posting Wim. I found that the published tables sometimes give just galactic coords for these galaxies and a lot of mathematical sin/cos gymnastics is needed to convert to equatorial. Though being discovered on photographic plates and such, you would think the equatorial would be noted first and then converted to galactic.

I haven't checked to see what apparent size it is but several around the Milky Way are in fact quite large and a wider FOV is needed for them to appear visible, being so faint, though this is unlikely for one around Andromeda. Maybe it shows up better in  the Infra Red spectrum. As several show NGC147 having two tidal streams it may be when viewed in other than visible light or Radio astronomy data. 🤔

It might be worth continuing if you would like to be known as the first to visually image Andromeda XXX 😊

Alan

[wimvb]

10 hours ago, symmetal said:

than visible light or Radio astronomy data. 🤔

Neutral Hydrogen is only ”visible” in mm wave data, ie through radio astronomy. Stellar streams consist of stars, and should be visible in optical wavelengths.

Like the dutch national coat of arms says: I will persevere. (Once the sky clears.)

[wimvb]

11 hours ago, symmetal said:

I haven't checked to see what apparent size it is but several around the Milky Way are in fact quite large and a wider FOV is needed for them to appear visible, being so faint, though this is unlikely for one around Andromeda.

In some of these galaxies, such as And XXX, the classification is done by photometric study of individual red giant stars. And XXX was discovered in 2012 as a local star density increase of only 8 such stars. Being roughly at the same distance as the Andromeda galaxy itself, this means that single stars need to be resolved. This is too much to demand from a 7.5” telescope situated in the Northern European climate. But if the stars create a diffuse patch, it may be possible to record it.

[symmetal]

Your perseverance will prevail. 😊

Alan