Arp 105, "The Guitar". NGC 3561 in Abell 1185 (Mau_Bard)

Arp 105, "The Guitar". NGC 3561 in Abell 1185

After three months of adverse weather, including strong winds, I had a full night available to image this wonderful galaxy cluster including Arp 105 "the guitar".

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Abell 1185 lies at around 433 million light years from our galaxy, and is moving away from us at a rate of 8700 km/s due to the cosmic expansion.
The cluster contains 82 confirmed member galaxies for which common red shifts have been found.

One of the cluster's brightest and most interesting objects is Arp 105, "the Guitar". The main protagonists in this maelstrom of interacting galaxies are the spiral galaxy (NGC 3561B) and the elliptical (NGC 3561A), along with a handful of tidal dwarf galaxies. The debris of their gravitational dance renders a shape reminiscent of a guitar.
A small tidal dwarf galaxy known as Ambartsumian's Knot is the blueish speck below NGC 3561, and it is believed to be the remnant of the extensive tidal tail pulled out of one of the galaxies.

The interacting galaxies are flinging out tidal arcs, sheets and knots of their constituent stars across hundreds of thousands of light years. Some of these will potentially form distinct gravitationally bound condensations of stars and gas in their own right - becoming tidal dwarf galaxies. It seems likely that the independence of these new systems can only be a temporary state of affairs, given their location in the middle of a cluster.

Near the center of Abell 1185 (just above the middle of our image here) lies NGC 3550, the brightest cluster galaxy. Look closely at it's center you will see that it contains a rare triple nucleus. These nuclei have greatly differing velocities and it seems that this is the result of a relatively recent set of mergers that has yet to settle down and the nuclei merge.

A close look to the image reveals a quantity of galaxy types and ongoing interactions.

Light Polluted skies
Optolong L-Pro filter
Broadband under Bortle 7/8/9
Imaged with N.I.N.A.
N.I.N.A. Users
ZWO ASI 2600MC PRO
Abell Galaxy Clusters
Imagers of Italy
Musical Imagers
Suburban Astrophotography
PixInsight Addicts

	Distinct awarded users	Total awarded images
Image of the day
Top picks
Top pick nominations

	Image of the day	Top pick	Top pick nominations	Total submitted
Deep sky
Solar system
Extremely wide field
Star trails
Northern lights
Noctilucent clouds
Landscape

	Image of the day	Top pick	Top pick nominations	Total submitted
Backyard
Traveller
Own remote observatory
Amateur hosting facility
Public amaeteur data
Professional, scientific grade data
Mix of multiple sources
Other
Unknown

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Status	Advanced success
Started	...
Astrometry.net job	5524621
PixInsight job	OBYUKTWQFM6HDCAK67HKOP752EFP50AW
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	11h10m47s.264
RA (top/left)	11h12m09s.812
RA (top/right)	11h09m25s.127
RA (bottom/right)	11h09m25s.338
RA (bottom/left)	11h12m08s.998

Dec (center)	+28°41′24″.92
Dec (top/left)	+28°59′21″.82
Dec (top/right)	+28°59′27″.30
Dec (bottom/right)	+28°23′26″.92
Dec (bottom/left)	+28°23′20″.95

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