by Ann » Sun Feb 27, 2022 5:34 am
alter-ego wrote: ↑Sat Feb 26, 2022 10:36 pm
Guest wrote: ↑Sat Feb 26, 2022 10:14 pm
Ann wrote: ↑Sat Feb 26, 2022 8:56 pm
I, too, have been unsuccessful.
If you go to
Simbad, you can actually see the galaxy, extremely faintly, to the right of NGC 4945. You can click on it to find out its coordinates, and you can ask Simbad to identify objects in the vicinity of NGC 4945. Well, I did so, and I had no luck. I believe that the galaxy in question is extremely faint, quite possibly fainter than 17th magnitude, and Simbad may simply not have a designation for it.
Ann
Very interesting! Thanks for the report
Galaxies:
LEDA 3097829
ESO 219-25
6dFGS gJ130634.9-493149
Thanks a billion, alter-ego! How did you do that, when I couldn't?
Anyway. LEDA 3097829 is obviously a low surface brightness galaxy - not a
tremendously low surface brightness galaxy, nothing like Malin 1, for example.
Wikipedia wrote:
Malin 1 is a giant low surface brightness (LSB) spiral galaxy. It is located 1.19 billion light-years (366 Mpc) away in the constellation Coma Berenices, near the North Galactic Pole. As of February 2015, it is the largest known spiral galaxy, with an approximate diameter of 650,000 light-years (200,000 pc), thus over three times the diameter of our Milky Way. It was discovered by astronomer David Malin in 1986 and is the first LSB galaxy verified to exist. Its high surface brightness central spiral is 30,000 light-years (9,200 pc) across, with a bulge of 10,000 light-years (3,100 pc). The central spiral is a SB0a type barred-spiral.
But LEDA 3097829 is nothing like Malin 1. The giant low surface brightness galaxy in Coma Berenices has a high surface brightness central spiral, but LEDA 3097829 has a very faint center. Then again, its center is yellow and its outer regions bluish (or, more likely, just intermediate-colored). Also LEDA 3097829 has a very elegant barred shape. This suggests that LEDA 3097829 is reasonably massive, in order to display such mass segregation and such an elegant barred spiral shape. LEDA 3097829 actually resembles an extremely faint version of barred spiral galaxy NGC 7479:
LEDA 3097829.Photo: Dietmar Hager, Eric Benson.
An interesting difference between NGC 7479 and LEDA 3097829 is that the barred spiral shape of the latter appears to be superimposed on a larger, featureless disk. Alternatively, the blue-gray stuff surrounding the bar of LEDA 3097829 is a large bright halo.
In any case, my guess is that LEDA 3097829 is rich in dark matter, because the puny stellar content of the galaxy just doesn't seem enough to create its elegant shape.
Ann
[quote=alter-ego post_id=320929 time=1645915018 user_id=125299]
[quote=Guest post_id=320928 time=1645913686]
[quote=Ann post_id=320927 time=1645909015 user_id=129702]
I, too, have been unsuccessful.
If you go to [url=http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+4945&submit=SIMBAD+search]Simbad[/url], you can actually see the galaxy, extremely faintly, to the right of NGC 4945. You can click on it to find out its coordinates, and you can ask Simbad to identify objects in the vicinity of NGC 4945. Well, I did so, and I had no luck. I believe that the galaxy in question is extremely faint, quite possibly fainter than 17th magnitude, and Simbad may simply not have a designation for it.
Ann
[/quote]
Very interesting! Thanks for the report
[/quote]
Galaxies:
[url=http://simbad.cds.unistra.fr/simbad/sim-id?Ident=LEDA+3097829&]LEDA 3097829[/url]
[url=http://simbad.cds.unistra.fr/simbad/sim-id?Ident=ESO+219-25&]ESO 219-25[/url]
[url=http://simbad.cds.unistra.fr/simbad/sim-id?Ident=6dFGS+gJ130634.9-493149&]6dFGS gJ130634.9-493149[/url]
[/quote]
Thanks a billion, alter-ego! How did you do that, when I couldn't?
Anyway. LEDA 3097829 is obviously a low surface brightness galaxy - not a [b][i]tremendously[/i][/b] low surface brightness galaxy, nothing like Malin 1, for example.
[float=left][img3="Malin 1, a low surface brightness galaxy. Image: SDSS/Giuseppe Donatiello"]https://upload.wikimedia.org/wikipedia/commons/thumb/5/5f/MALIN_1_%28post-processed%29.jpg/1024px-MALIN_1_%28post-processed%29.jpg[/img3][/float]
[clear][/clear]
[quote][url=https://en.wikipedia.org/wiki/Malin_1]Wikipedia[/url] wrote:
Malin 1 is a giant low surface brightness (LSB) spiral galaxy. It is located 1.19 billion light-years (366 Mpc) away in the constellation Coma Berenices, near the North Galactic Pole. As of February 2015, it is the largest known spiral galaxy, with an approximate diameter of 650,000 light-years (200,000 pc), thus over three times the diameter of our Milky Way. It was discovered by astronomer David Malin in 1986 and is the first LSB galaxy verified to exist. Its high surface brightness central spiral is 30,000 light-years (9,200 pc) across, with a bulge of 10,000 light-years (3,100 pc). The central spiral is a SB0a type barred-spiral.[/quote]
But LEDA 3097829 is nothing like Malin 1. The giant low surface brightness galaxy in Coma Berenices has a high surface brightness central spiral, but LEDA 3097829 has a very faint center. Then again, its center is yellow and its outer regions bluish (or, more likely, just intermediate-colored). Also LEDA 3097829 has a very elegant barred shape. This suggests that LEDA 3097829 is reasonably massive, in order to display such mass segregation and such an elegant barred spiral shape. LEDA 3097829 actually resembles an extremely faint version of barred spiral galaxy NGC 7479:
[float=left][attachment=0]LEDA 3097829 in the field of NGC 4945 APOD February 26 2022.png[/attachment][c][size=85][color=#4040FF]LEDA 3097829.Photo: Dietmar Hager, Eric Benson.[/color][/size][/c][/float][float=right][img3="NGC 7479. Photo: Göran Nilsson/The Liverpool Telescopes."]https://upload.wikimedia.org/wikipedia/commons/thumb/e/e6/NGC7479_Goran_Nilsson_%26_The_Liverpool_Telescope.jpg/1229px-NGC7479_Goran_Nilsson_%26_The_Liverpool_Telescope.jpg[/img3][/float]
[clear][/clear]
An interesting difference between NGC 7479 and LEDA 3097829 is that the barred spiral shape of the latter appears to be superimposed on a larger, featureless disk. Alternatively, the blue-gray stuff surrounding the bar of LEDA 3097829 is a large bright halo.
In any case, my guess is that LEDA 3097829 is rich in dark matter, because the puny stellar content of the galaxy just doesn't seem enough to create its elegant shape.
Ann