I was looking at a recent paper about a grand spiral galaxy at z = 5.2:
And I was wondering how it compared to large spirals today. So here is a large spiral galaxy at z = 0.119. Does anyone know of a larger spiral galaxy? The arms of this galaxy have a very low surface brightness.
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I would also put rubins galaxy in this list since it is 134.3 kpc across. Not sure if that means those extended arms or if that it the disk in the middle.
https://en.wikipedia.org/wiki/UGC_2885
This is where you can download full JWST images of this location.
That is really interesting. I had posted this galaxy in Pegasus Z 376-49 previously because it looks to be enormous. The outer reaches of it though dimmer must be filled with stars. It could be as wide as 25-30 arc seconds on the viewer. I would love to have more detailed images and measurements of it.
I know Arcsecs on the viewer are a poor measuring tool for a galaxy, but I wonder if the measurements for it account for its true size?
This is a really cool looking face on spiral.
With **V(km/s) 8797 [21] / z(~) 0.02979 [0.00007] **
Making this galaxy about D = 8797/70 = 125.7 Mpc away.
With a width of about 0.0104 degrees from side to side about 37 arcsec using two different coordinates on either side. Converting radians (0.0104)pi/180 = 0.0001815
This gives a scale of about d = (0.0001815) (1000kpc/Mpc) (125.7 Mpc) = 22.8 kpc in diameter making it smaller than the Milky way of about 30 kpc.
I was hoping it was going to be larger too…
Actually I just realized that this galaxy does extend a little further out after I reread your comment so it could be the same size as the milky way, potentially. The fringe is a bit dimmer than the main disk, though.
By the way in the paper of Zhulong they give a diameter of about 19 kpc using cosmological parameters: M = 0.3, L = 0.7, H0 = 70 km/s/Mpc This corresponds to an angular diameter distance of 1271 Mpc. However, if we take the same angle on the sky but change the cosmology to a de Sitter Steady State we get an angular diameter distance of 3592 Mpc, significantly larger, making the Zhulong galaxy a whopping 54 kpc in diameter.
My calculations in desmos 
