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Contains:  NGC 548, NGC 547, NGC 545, NGC 543, NGC 541, NGC 535, NGC 538, NGC 530
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Abell 194: A Mini Markarian's Chain & Eintstein-Straus Vacuole, 





    
        

            Robert Churan
Abell 194: A Mini Markarian's Chain & Eintstein-Straus Vacuole

Abell 194: A Mini Markarian's Chain & Eintstein-Straus Vacuole

Technical card

Resolution: 5200x3475

Frames:
ZWO Blue 1.25": 20x512"
ZWO Green 1.25": 20x512"
ZWO Luminance 1.25": 60x512"
ZWO Red 1.25": 20x512"

Integration: 17.1 hours

Darks: ~50

Flats: ~50

Bias: ~50

Astrometry.net job: 2982230

RA center: 21.372 degrees

DEC center: -1.407 degrees

Pixel scale: 0.382 arcsec/pixel

Orientation: 1.418 degrees

Field radius: 0.332 degrees

Data source: Backyard

Description

A beautiful galaxy cluster of over 100 members some 265 million light years from us in the constellation of Cetus. This cluster is notable for its high "population density" of lenticular (S0) galaxies.

This cluster reminded me of Markarian's Chain at first, complete with its own set of "Eyes" with lenticular (S0) NGC 545 and elliptical (E) NGC 547 located near the top left. Down and to the right you find an elliptical galaxy, known as NGC 541, a radio galaxy of Fanaroff-Riley class I. 45 seconds of arc due northeast of NGC 541 lies Minkowski's Object. This is a small irregular dwarf galaxy undergoing incredible star formation. It lies within the radio jet of NGC 541, and current models suggest it was cooled by the jet, triggering high rates of star formation. That was the original appeal of this cluster to me, but as I researched it, I found something that set off my "nerd alarm" to an extreme degree.

This cluster, like our own local group of galaxies, is surrounded by an Einstein-Strauss vacuole. Not much information is available on this phenomenon. From what I found: This is a sperical Schwarzchild region immersed in a Friedmann universe with a metric obtained by solving the equations of general relativity of a mass condensation in an expanding universe with vanishing cosmological constant. The results obtained tend to suggest that cosmological expansion from dark energy has no effect on dynamics even on the scale of galaxies and gravitationally-bound galaxy clusters. A paper from 2005 by R. Plaga explores how the Einstein-Strauss vacuole hypothesis applied to the case of ACO 194 predicts better values for galactic redshift than those obtained from the cosmological concordance model.

It was difficult to pull data from this object, as guiding at a low declination of -1° from my latitude on a severely undermounted rig is a task which requires a string of miracles. Despite troubles with declination, I'm reasonably pleased with how this one turned out.

Cheers to all,
Rob

Comments

Author

Soundologist
Robert Churan
License: None (All rights reserved)
390
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Abell 194: A Mini Markarian's Chain & Eintstein-Straus Vacuole, 





    
        

            Robert Churan