Object of the Week January 13, 2013 NGC 2207 and IC 2163 (Cosmic Ballet)

[Jimi Lowrey]

NGC 2207

Canis Major

Ra
06 16 22

Dec
-21 22 22

Type SB (rs) bc PEC

Mag 12.2

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IC 2163

Type SB (rs) PEC

Mag 11.6

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NGC 2207 and IC 2163 were found by John Herschel in 1835. They are in close interaction and in several billion years will form into one galaxy. The calculations indicate that IC 2163 is swinging past NGC 2207 in a counterclockwise direction, having made its closest
approach 40 million years ago. However, IC 2163 does not have sufficient energy to escape from the gravitational pull of
NGC 2207, and is destined to be pulled back and swing past the larger galaxy again in the future. Strong tidal forces from NGC 2207 have distorted the shape of IC 2163, flinging out stars and gas into long streamers stretching out a hundred thousand light-years.

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This is one of my favorite winter time galaxies that I return to year after year. I often have wondered why it is not in Arp's Catalog of peculiar galaxies? This one sure is interesting.

438

Be sure to check out this "cosmic Ballet" in the Big Dog next time you are out and,

"GIVE IT A GO AND LET US KNOW"

GOOD LUCK AND GREAT VIEWING!

[lamperti]

How ironic that you posted these two! I observed them last Monday and thought I detected some mottledness in NGC-2207 at 337x.
Al

22"U.C.

[Howard B]

439440

Hi Jimi,

I had a good look at these two in 2009 from Steens Mountain under an excellent sky. 2207 seemed to have a double core at 408x with my 28 inch but the two photos you've posted don't show this. Anyway, here's my quick sketch from 2009. I made this sketch just as dawn was just starting to show so even though the SQM was 21.9-ish just before I started sketching, the sky was probably in the 21.5 range as I made this sketch.

[Ivan Maly]

Fascinating object and sketch. On the Hubble photo of NGC 2207 the smaller object of the "double core" in Howard's sketch is stellar, white, and much brighter than the brightest red, starlike HII region. Probably a superimposed star.

[Jimi Lowrey]

There is a challenge object that is close to this group. Off the East end of IC 2163 is the galaxy 2MASX J06163579-2122032 it shows up well in this DSS image

441

I'm not sure of the MAG of this galaxy but I would guess it to be 16 to 17 MAG range. I also could not find the Z of this galaxy so I am not sure if it a back ground galaxy or a dwarf companion of IC 2163. If you can catch its faint glow I know of no observations at this time and am sure you might be one of the first people to see this galaxy visually.

This is a ESO image that shows the 2MASX galaxy well

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[Dragan]

My first experience with this object came on the night of the 23 of February back in 2009. Here are my notes from that night.

TeleVue Ethos 13mm, 375x
A trainwreck of an interacting pair Both arms visible on 2207. Main arm of IC 2163 visible. a superimposed star(?) on 2207 was apparent. Unable to confirm the MAC but during moments of steady seeing I' do see something there. Have to revisit this one.

I make mention in my notes of a MAC. Looking at Megastar, one MAC appears to be off the arm of IC2163 while the other appears to be Jimis challenge object. >ooking at the pictures above that Jimi posted, I'm not so sure now that's what we were looking at. I wonder which MAC my notes refer too. We would have been using Megastar that night so it can be either. I just don't remember. *sigh*

I really really have to get get better at taking notes.... :(

[Paul Alsing]

This is another object that I viewed through the 82" up the road from Jimi in 2006...

"NGC 2207 and IC 2163 are 2 interacting spiral galaxies that are framed perfectly by the 5 arc minute FOV, and they were one of most pleasant surprises of the entire weekend. 2207 is fully face-on and has a classical shape, the arms are broad and distinct and easy to see at this aperture, and the spiral structure seems to go all the way into the center. 2163, on the other hand, is kind of "eye" shaped and has a showy tidal tail trailing outwards from the pair, but does not reveal much spiral structure in the eyepiece. Perhaps the best pair of the weekend."

[Jimi Lowrey]

Dragan,

The MAC objects are not the 2MASX galaxy that I posted as the challenge object.

One of the MAC objects is a H II knot on the east end of IC 2163. The other MAC object is a triple star south of the group. hope this helps.

[Jimi Lowrey]

Howard,

I was looking at your sketch and it looks like you might have seen the 2MASX galaxy. You show something in your sketch that looks like it is in the right place?

Also it looks like you have the faint double star that is near the galaxy. What do you think?

[Howard B]

Hey Jimi, after looking at my original sketch I don't think I saw the 2MASX galaxy and I'm not sure which double star you mean. The only double in my sketch is outside the crop I made for my post above. Man, I'd love another crack at this one!

[Jimi Lowrey]

Howard,

Look at this image and you will see the double star off the end of IC 2163.

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[Steve Gottlieb]

Here are my notes using Jimi's scope last February. What a beautiful object! The HII knot on the east end of IC 2163 is mentioned below ---

48" (2/20/12): this beautiful spiral galaxy forms a stunning pair with IC 2163, attached to its east side. Sharply concentrated with a brilliant nucleus embedded in a very bright core. On the WSW edge of the core a mag 13.5 star is superimposed. A couple of beautiful, winding spiral arms are visible in the halo. An outer arm is on the southern end of the galaxy stretching to the west and curving counterclockwise north towards a mag 12.5-13 star situated 1.7' NW of center. A second arm more inner arm vaguely emerges on the west side of the core and wraps counterclockwise to the north, where it is parallel to the outer arm described above. This arms then curves back east of along the north side of the halo, stretching to the NE side of the halo, but not reaching IC 2163.

IC 2163 is attached at the east side of NGC 2207. The central region is very bright, round, ~1' diameter, with a small bright core. Attached on the southwest side is a spiral arm that gracefully sweeps to the east while curving gently clockwise. The arm is ~1.5' long and significantly increases the overall size to roughly 2'x1'. Just NE of the tip of the arm is 2MASX J06163579-2122032, which appears as a faint, very small knot (possibly a galaxy or an HII knot).

[Howard B]

I see which one you mean in the photo Jimi but this double isn't in my original sketch. I'll certainly look for it next time though.

[Steve Gottlieb]

Jimi, I'm pretty sure the object I logged as 2MASX J06163579-2122032 with your scope is the 2MASX one you're referring to, and not the nearby MAC. But I didn't mention the nearby double star.

[Uwe Glahn]

Great pair of interacting galaxies Jimi.

This pair is difficult to resolve under typically German skies (48°N-54°N) because of its low altitude. I could never detect the spiral structure nor the interacting structure between the galaxies with my 16". From La Palma (29°N) these structures became much easier to detect, even with smaller aperture (14,5")

14,5", 202x-283x, NELM 7m+
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sketch (http://www.deepsky-visuell.de/Zeichnungen/NGC2207_IC2163.htm)

Rainer Mannoff observed this group also from Marokko (30°N) with 16" and saw pretty much the same (sketch (http://www.mannoff.de/zeichnungen/NGC2207.htm)

We both could not see the faint DS and the fainter galaxy in the E.

[RolandosCY]

Ahmmm, ahmmm.... I was about to post my December 31st OOTW, featuring... Well, you guessed it! NGC 2207 and IC2163! I had just decided to have a quick look for additional observations in the web, when I came across the ... January 13th 2013 OOTW! Oh well, can't believe |I missed it while checking the previous years. well, since I did the effort, here is my write up for the record.... Dragan and Jimi, give me another couple of days for another OOTW!
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Object of the Week, December 31 2017: NGC 2207 and IC 2163
Winter evenings can be cold or frigid cold, but when the skies are clear, the starry vistas can be spectacular. The winter Milky Way arches above, straddling Orion the Hunter and his dogs, Canis Major and Minor. These areas are famous for the never ending array of nebulae and star clusters, but hidden amongst the myriad stars and the clouds of hydrogen and dust, are some fine galaxies, such as this week’s objects: the NGC 2207 and IC 2163 colliding pair.

Both galaxies, which reside in the southwest corner of the Great Dog, were discovered by John Herschel in 1835, and they are estimated to be around 85 million light years away. They are of a great astrophysical interest, as they are in the early stages of their collision. Both galaxies still have their original characteristics, but they do show some signs of the impeding situation. NGC 2207 is a SAB(rs)bc peculiar galaxy with a weak ring around the central bar. IC 2163 is a SB(rs)c peculiar galaxy, smaller in physical extend than 2207, that also has a weak inner ring, and a long elongated arm, possibly stretched due to tidal interactions with the larger galaxy. Both members of the pair show high rates of star formation, this being another result of the merging process. NGC 2207 has been quite an active supernovae producer, with four supernovae being recorded between 1975 and 2013.

My personal interest with this interacting galaxy pair started quite recently, thanks to a Sky and Telescope article by Richard Jakiel (February 2016, “Hunting Beneath the Dog”). On page 55 of that issue, a beautiful photo by the NASA/ ESA/ Hubble Heritage Team definitely attracted my attention. Although the article was written two years ago, I did not get around to observing the colliding galaxies until the Thanksgiving evening of 2017! Although the night was far from spectacular, using my 18” dob I could readily detect the pair as two distinct but touching fuzzies even at low power, with one fuzzy patch bigger and brighter than the other one. Increasing the magnification revealed NGC 2207 as an oval haze with a distinctly brighter starlike core, while IC 2163 was a softer, round, uniform patch. At the time of my observation the pair was still below their maximum altitude, and the unsteady seeing hindered my attempts to pull out more detail, though I could suspect more structure, especially in NGC2207. I did not even attempt a drawing, expecting to draw the pair in a better evening. Unfortunately, I was not able to observe again after that night, so I still need to go after this beautiful pair on a good night!

Checking old notes, I discovered that I had observed NGC 2207 before, with my 12” dob back in 2009, but I had not penned any further notes, nor did I mention any observations of IC2163. This is surprising as both galaxies are certainly within range of such an aperture. Actually, they should certainly be within range of a four-inch refractor given a good night and dark enough skies – something which I plan to attempt on my next night out!

Until then, whenever you are out gain this winter and the moon is gone, turn your scope to southwest Canis Major, fish out NGC 2207 and IC 2163, and as always….

Give them a go and let us know!