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Sausage Globular Clusters - wreckage of the Gaia - Enceladus event, Claudio Tenreiro

Sausage Globular Clusters - wreckage of the Gaia - Enceladus event

Getting plate-solving status, please wait...
Sausage Globular Clusters - wreckage of the Gaia - Enceladus event, Claudio Tenreiro

Sausage Globular Clusters - wreckage of the Gaia - Enceladus event

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Description

By chance I arrived into the interesting history behind a number of globular clusters labelled with this funny name "Sausage Globular Clusters". It is believed that around 15% to17% of the Globular Clusters are related with the so called Gaia - Enceladus event, in which the Milky Way "ate" a dwarf galaxy, and they were accreted by the event, from the parent galaxy. They are the clusters under this "category". It is also interesting that a star that is part of a cluster has the possibility to continue as part of it, and not be carried away by the tidal forces.

I started from Wikipedia, of course, https://en.wikipedia.org/wiki/Gaia_Sausage but soon arrived into quite interesting aspects of such an event. The name "The sausage globular clusters" is the title of a paper on the matter by Myeong et al, AJL 863:L28-2018- the name it has nothing to do with anything visual. From the table with 10 clusters in that paper, 8 are in the composed image I am showing here, as a collage of individual images.
They were taken with my gear, with the vantages and limitations of it, but the more complicated aspect was handling with the weather and quality of the seeing.

All of the images are a bit more than 2 hr of data each, stacked from 120" individual shots, using an OSC (ZWO294MC Pro) and the ED80 Refractor + NINA.

If you see the individual higher resolution images you will realize that all the centres are not burned out during the processing (in the composed, low resolution image ,seems otherwise), and this is something visual which is interesting, all these clusters seems to have a not so dense core, and certainly not a collapsed one.
I reprocessed all the images following exactly the same steps to build the collage, focusing just in the cluster. Some small differences in the background can be seen, I believe it is due to the difference in seeing/pollution on different nights.

Using PxI: Crop to 2048x2048 pixels-ABS-Photometric Cal-SCNR at 95% green removal, Histogram to adjust Black, Slow and manual stretching using Histogram- 2x slight colour saturation and 2x S curves for contrast enhancement. 

Anyway, it was real fun to realize the existence of the connection between these clusters, beyond its common shape.

NGC2298: https://www.astrobin.com/ajorje/
NGC1851: https://www.astrobin.com/5skgti/
NGC1261:https://www.astrobin.com/pihxxf/
NGC362:https://www.astrobin.com/ga03su/
NGC5286:https://www.astrobin.com/ychbai/?nc=collection&nce=2305
NGC2808:https://www.astrobin.com/005hlr/C/?nc=collection&nce=2305
NGC7089:https://www.astrobin.com/l30z9j/?nc=collection&nce=2305
NGC6864:https://www.astrobin.com/pblbr3/?nc=collection&nce=2305

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