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View Full Version : Object of the Week August 28, 2016 ARP 118 A Triple Encounter



Jimi Lowrey
August 28th, 2016, 02:00 AM
ARP 118

Cetus

RA
02 55 11
DEC
-00 10 58
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NGC 1144

Type Seyfert 2

Mag 13.7 V
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NGC 1143

Type E

MAG
13.6 V
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2MASX j02550661-0009448

Type S0

MAG 15.7 V
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This weeks OOTW is ARP 118 a triple crash that is forming a ring. I selected it from Dr Berry Madore's paper "Atlas of Collisional Rings"http://arxiv.org/abs/0902.4629 It was originally thought that NGC 1144 was only interacting with NGC 1143 but after Dr Madore's 2009 paper it was shown that there is a third player in this cosmic dance. NGC 1143 is the main collider but 2MASX j0255-0009 has also had a encounter with NGC 1144.

2234

I find it fascinating to track down the collider galaxies that has caused such havoc in the formation of ring galaxies. At 15.7 V Mag 2MASX j0255-0009 is a bit of a challenge but is within reach of many scopes in this form. Another challenge with this system is to try and ferret out the ring in NGC 1144 very cool to see this early ring in formation! Another challenge near this system is the small galaxy 1.5' West of 2MASX j0255-0009 at 16.4 V Mag it is 2MASX j02550068-0009498. I look forward to here your observations of this triple cosmic dance and as always,

GIVE IT A GO

Uwe Glahn
August 28th, 2016, 11:10 AM
Have a very old observation and sketch with 16". Unfortunately without ring structure. Definitively a reason to re observe the Arp.

16", 360x, NELM 6m0+
2235

Jimi Lowrey
August 28th, 2016, 03:01 PM
Uwe nice to see you got the 2MASX galaxy with a 16"

wvreeven
September 5th, 2016, 09:42 AM
With my 20" I couldn't see the ring either this past Saturday. SkyTools has the designation LEDA 1150350 for the faint companion. My notes:

NGC 1144: At 545x visible with NGC 1143 and LEDA 1150350. NGC 1144 is the largest of the group. A stellar nucleus with a large featureless halo. A faint star lies to the south east.
NGC 1143: At 545x visible with NGC NGC 1144 and LEDA 1150350. Small, compact with a stellar nucleus.
LEDA 1150350: At 545x visible with NGC 1144 and NGC 1143. A faint smudge.