Object of the Week, June 15 2014: NGC 5544/5545, the “Exclamation Marc” Arp 199

[Uwe Glahn]

NGC 5544/5545 (Arp 199, VV 210, KPG 422)

Bootes
14 17 04
+36 34 24

NGC 5544
13,0vmag; 1,0’x1,1’; SB0-a

NGC 5545
15,0vmag; 1,0’x0,3’; Sbc

First known observation came from William Herschel 1785 with his Speculum 18,7-inch telescope. He saw and catalogs only one object but it was his son John who suggests a separation into two objects. William Parsons confirmed this separation 1852 with his 72 inch Leviathan and noted “either a double nebula or two knots of one nebula”.

Later, the both famous catalogs for interacting and abnormal galaxies Vorontsov-Velyaminov and Arp enter the pair as numbers 210 or 199. Arp’s classification is “material ejected from nucleus” with his notes “spirals appear disturbed”

Astrophysical both galaxies have the same distance of around 44 Mpc and their different radial velocities shows the interaction between them. Although the galaxies seems to be a collision pair photographs shows no strong interaction structure. Only very deep photos shows big HII and blue star burst regions in NGC 5545 and shows some dark zones in the overlapping region. This is also the topic of a new paper of Donovan L. Domingue et al. 1999

Visually the pair is more difficult than the NGC designation looks like. First target in mid size telescopes is to separate both galaxies. With 16” it was not a problem to see both as single objects - NGC 5545 as a fainter 3:1 elongated strip which sits directly NE on the small but brighter NGC 5544. In mid size telescopes the “exclamation marc” appearance is best. With bigger telescopes the periphery of NGC 5544 started to be visible – NGC 5544 becomes bigger, with a brighter part in the NW. NGC 5545 started to be structured also – the brightest spiral arm segment becomes visible at the NE end.

But, what do you see?

big_arp199.jpg
200-inch Palomar plate
- Dr. Barry F. Madore; Caltech and Carnegie; Pasadena, California, USA -

n5544s_11.jpg
32-inch Schulman Telescope
- Adam Block/Mount Lemmon SkyCenter/University of Arizona-

NGC5544_NGC5545.jpg
27-inch, 586x, NELM 7m+, Seeing I
(inverted version)

“GIVE IT A GO AND LET US KNOW”
GOOD LUCK AND GREAT VIEWING!

[Ivan Maly]

Very dynamic view in that sketch!

[Dragan]

Uwe,

If I had ever thought of describing this object as an "exclamation mark", I may have written about it here at DSF. But unfortunately, I never submitted it as an OOTW as it was originally shown to me in 2003 with a different moniker, "The X-Rated Galaxy".

I really don't think I'll have to explain.....

[RolandosCY]

Uwe,

If I had ever thought of describing this object as an "exclamation mark", I may have written about it here at DSF. But unfortunately, I never submitted it as an OOTW as it was originally shown to me in 2003 with a different moniker, "The X-Rated Galaxy".

I really don't think I'll have to explain.....

I don't think I have ever had such a laugh with something written in an astronomy forum before!!!!
Jokes aside, it looks like a very interesting target for my 18"!!!

[Uwe Glahn]

Dragan,

"X-Rated"...you can explain it when you want to

I remember NGC 520 as "X-Rated"...but I don't explain why

I don't know where the moniker "exclamation marc" came from. I know this object for years under this name. I always thought that it came from you US guys but apparently not? Who cares...but definitely cool object.

[Ciel Extreme]

THAT... is a superb drawing...

[davidem27]

Uwe, it's a splendid viewing.
Perfect sketch, as usual.


Oh my...!
Good to read you, Mark.
Great job for the CGHO: http://www.volpetta.com/risorse/libri#herschel-2500

[Jimi Lowrey]

The fist place I read of Arp 199 called the X-Rated galaxy was at Adventures in Deep Space web site many years ago. Maybe Steve G will jump in here and tell us were the name came from.

Great drawing of this beautiful cosmic collision Uwe.

[Steve Gottlieb]

I had a feeling someone would reveal I was the culprit. I don't know, the name just came to me.

[KidOrion]

Sometimes an edge-on galaxy is just an edge-on galaxy.

[Marko]

A subtle comment that people here have seriously large telescopes is the comment of 'In a 16" ... "in mid-sized scopes" ...

So when 16 is apparently 'small' 'mid sized' must be 24 and large is over 30. LOL Love this forum.

Great pair and I will try this for sure in my 'small' 18" dob.

[Jim Chandler]

A subtle comment that people here have seriously large telescopes is the comment of 'In a 16" ... "in mid-sized scopes" ...

So when 16 is apparently 'small' 'mid sized' must be 24 and large is over 30. LOL Love this forum.

Great pair and I will try this for sure in my 'small' 18" dob.

For what it's worth, my wife's 18" f/4.5 is affectionately known as "Mighty Mite".

[Dragan]

For what it's worth, my wife's 18" f/4.5 is affectionately known as "Mighty Mite".

Um, Jim. I though Ana's scope had a different nickname?

[akarsh]

I must admit to having had a list of X-rated objects, and I was checking them off, this one included. So I observed this on one of the days. My observing report marks an elliptical base and an extension, that was observed to be "long". It was quite easy in my 18" from Bortle 2-ish skies.

Clear Skies
Akarsh

[Jim Chandler]

Um, Jim. I though Ana's scope had a different nickname?

More years ago than I care to count, it was named "The Big O". Starting roughly with the UGC 9242 incident, say five years ago, Mighty Mite came into being. The wheel turns.

[Clear Skies]

This with a 'tiny' 12" SCT in 2011 (179x / 27'):

Both galaxies are visible, both are quite faint. The WSW galaxy is NGC5544: Slightly elongated east to west with quite a bright nucleus that is visible when using AV.
The ENE galaxy is NGC5545: Slightly elongated ENE-WSW, even in brightness.
1/4 FoV to the NW is a mag. 8 star with a mag. 9 star to its NW.

[RolandosCY]

And here is my sketch from a few nights ago. Not particularly hard to detect, rather brighter than expected. NGC5544 is round, bright 9with a brighter center), while 5545 is longish, again with a brighter longish center. The two galaxies appeared at 294X to be touching each other...

5544a1.jpg

[RolandosCY]

And here is my sketch from a few nights ago. Not particularly hard to detect, rather brighter than expected. NGC5544 is round, bright 9with a brighter center), while 5545 is longish, again with a brighter longish center. The two galaxies appeared at 294X to be touching each other...

5544a1.jpg

By the way, the duo was visible in my 6" achro as a longish, but generally undefinable hazy faint patch at 128X. With direct vision I could see that "something" was there, with averted vision that "something" would become longish, sort of like an extremely faint version of NGC 3115! I couldn't though detect any details with the 6". I plan to try it with the 6" and a higher magnification as well, but I must admit I was surprised that even under my SQM 21 skies I could detect it in the refractor!