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Old 20-11-2020, 07:45 AM
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madbadgalaxyman (Robert)
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Here is an HST image , taken with the F606W filter (approximately V band)("visual" wavelengths, so to speak)

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The sprinkling of cinnamon (OB stars, chains of hot young luminous stars, spiral arms, etc.) is emphasized!
But , if there is any peculiarity in this galaxy, it would be the underlying spheroidal component, rather than the spiral structure.
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I am going to assume that this galaxy is no more than 10 megaparsecs (= 32.6 million light years) away, based on the degree of resolution of its brightest stars by HST and based on its redshift .

[[ I am assuming a ballpark estimate of its distance, based on its recession velocity, of 32 million light years. In other words, I am assuming this galaxy has a distance modulus of (m-M) = about 30 )

So, yeah, I do reckon that this extragalactic critter Really & Truly is a low luminosity Spiral Galaxy, as there exists a total (integrated) B magnitude of 13.93 in the Hyperleda database, and then we just apply the distance modulus to get an estimate of its Absolute Magnitude.
(nonetheless, the extant data on this galaxy is scant and of poor quality)

This seems to me to be the most parsimonious interpretation;
for I think that it is the safest bet (for now) to follow the limited available data; and thus to , at least initially, make the simplest interpretation.
(one which, of course, may later be modified)

But, Dana (my oracle on Stellar Astronomy), here is a question for you.....
are those actually resolved Red Supergiant stars in the HST image, as seen within the circular/spheroidal subcomponent of this galaxy?
( see the highest resolution version of the HST image at www.spacetelescope.org )
If so, this would be peculiar, as most of these dwarf galaxies have old or intermediate-aged spheroidal components.

In respect of your provocative hypothesis that this galaxy could have a very large peculiar velocity - that it is falling or orbiting at very high speed in the vicinity of a distant galaxy cluster -- I note that these 'peculiar' (non-cosmological) velocities of galaxy Infall and/or Orbit never seem to reach more than 2000-3000 kilometers per second, as measured spectroscopically (when we observe a galaxy from the direction of our line-of-sight).

So I conclude that this Interesting Extragalactic Critter is more likely to be a relatively nearby galaxy.

But I need to find more Hard Data on this galaxy!
......Not as easy as it used to be, as I have been entirely focused on the Ground Beneath My Feet for the last four years! (cataloguing soil arthropods, in particular!!!)

For, once upon a time, I knew (and used!) Every Source of galaxy data and galaxy imagery that exists in the whole entire known universe.....
but those days are well in the past.
( as for those galaxy Data Sources that are located somewhere in the Unknown Universe, who knows?)

Last edited by madbadgalaxyman; 20-11-2020 at 03:57 PM.
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