Object of the Week - March 26, 2017 - NGC 3067 / 3C 232

[Uwe Glahn]

Leo

NGC 3067
Ra: 09 58 21
Dec: +32 22 12
Mag (b): 12.0
z=0.005
Light Travel-Time: 0.078 GLy

3C 232
Ra: 09 58 21
Dec: +32 24 02
Mag (g): 16.1 [NED]
Mag (b): 16.0 [USNO B1]
Mag (b): 15.7 [NOMAD1]
z=0.531
Light Travel-Time: 5.097 GLy



Another astonishing pair of two near (1.9’) discordant objects – galaxy NGC 3067 and the quasar 3C 232.

NGC 3067 was discovered by William Herschel in 1785. The active central region means that this galaxy is a starburst galaxy.

The mystery began in 1971 [1971ApJ...170..233B] when Burbidge et al. uses the 3C radio sources catalogue which maps the object 3C 232 only 1.9 north of NGC 3067. From the common distance calculation from the redshift the quasar is around 65 times behind the galaxy. But than, the discussion began.
- Arp [1989ESOC...32...89A] shows a hydrogen bridge between the quasar and the galaxy.
- Arp and Burbidge [1990ApJ...353L...1A] shows that the jet of 3C 232 is pointing in the direction of the galaxy 3C 232
- Stocke et al. [1991ApJ...374...72S] presents a picture of a “HI finger” which connects the quasar and the galaxy but they estimated no real tidal connection and only a chance projection of both objects.
Several other paper were written to explain the near pair but the mystery still remains.

Nevertheless the professional studies the pair is another very interesting pair to observe in amateur telescopes. While NGC 3067 is visible
even in very small aperture, the quasar could be in reach of a 12-inch telescope.

27", 419x, NELM 6m5+, Seeing III
2519

As always, give it a go and let us know

[Ivan Maly]

Excellent detail in the sketch. I viewed the galaxy recently in 12" ("bright, lens-shaped") but could not locate the quasar. Next time.

[Steve Gottlieb]

Here's my last observation of the galaxy. I don't believe I looked for the nearby quasar, so thanks for the suggestion!

24" (4/20/14): fairly bright, elongated 5:2 WNW-ESE, 1.3'x0.5', contains a large bright core that is very mottled with several very small knots (HII regions and dust on the SDSS). The southeast side of the halo is weaker with an irregular surface brightness. A mag 9.8 star is 3.9' ENE.

[Steve Gottlieb]

I had another chance to take a look at NGC 3067 with my 24" under SQM 21.5 skies. The quasar was easily visible as a mag 16 "star" -- thanks for highlighting this interesting galaxy/quasar pair!

[Robin]

the quasar could be in reach of a 12-inch telescope.

As always, give it a go and let us know


Hi Uwe,

When I read this, my first thought was "challenge accepted". :-)

Last Monday I experienced the most transparent sky at my location since one year. At twilight I could see the earth shadow clearly, later on the zodiacal light and even the Gegenschein, NELM at zenith was 6.8 mag. Probably the best opportunity to go for this quasar.


NGC 3067

With my 12-inch Dobsonian at 47x magnification I immediately saw an elongated patch. At 275x magnification I saw more details than I expected. It almost appeared like a small version of Messier 82. Longish with a little bulge near the center, surrounded by a very elongated, but diffuse, outer region.


3C 232

I spent 30 minutes on this object. With a 12-inch telescope, it is certainly not something to observe spontaneously within only a minute. I had to take all kinds of measures to detect as faint objects as possible. At first I studied my printed star chart, but then I only looked into the eyepiece for the rest of the time to avoid stray light from getting into my eyes. Then I moved the field of view back and forth several times to see the region of interest with different parts of my retina in order to find the averted vision sweet spot.
After a while I saw a faint stellar object at the right position. Then I let the field move through my eyepiece again and again with sidereal rotation and could reprodicibly see it every time. 16 mag is not easy with this aperture, but it is possible given the right conditions.
In order to figure out how faint I could see, I was also looking for the 16.6 mag star between the quasar and the galaxy, but I couldn't see that one. 16 mag was certainly close to the limit.
I think it is impressive that other than most faint stellar objects in the field of view, this is not some milky way dwarf star, but an extremely luminous object 5 billion light years away. According to generally accepted theory at least... As soon as the weather will be bad, I should read the discordant redshift papers that you provided the links to. :-)

Please find attached my sketch of this object.


Clear skies,

Robin

[Norman]

Nice observation Robin!

This object is on my list now... i´ll try to second your results.

CS
Norman

[Uwe Glahn]

Wow, thanks for the positive feedback Robin. 12-inch is really a tough aperture to get in reach of the QSO. Congrats for the success.

[Ciel Extreme]

Observed on Friday, April 14 with a 22-inch reflector, magnification 303x, stars +5.8-6.0 visible naked eye: “NGC 3067 is a large and bright galaxy, oval and oriented ESE/WNW with a grainy and slightly uneven surface brightness across the disk. Moderately well defined at the edges. The quasar 3C 232 is readily seen to the north of the core of NGC 3067, the “apex” star in the flat triangle of equally bright stars (mag. +16.0) to the NNW of the galaxy.”

[Robin]

Hi Uwe et al. :-)

Thank you Uwe and Norman for the nice feedback! :-)

Due to several days of bad weather I finally had some time to read the papers mentioned in Uwe's first post. I'm wondering about a structure that can be seen in Figs. 1 and 2 of the 1989ESOC...32...89A paper: At the left upper side with respect to the galaxy core there is a bright (dark in the negative image) blob.

If you look at my drawing, there is a little extension that I have seen at the lower side (north-east). By the way, I sketched it without prior knowledge of any photographs of this galaxy.
The extension can be seen more clearly in Uwe's nice drawing, in which it is even separated nicely from the galaxy core. Uwe's drawing has the same orientation as Figs. 1 and 2 of this paper. It seems as if this could the same structure, albeit at better resolution.

Now I wonder what this is. It can be seen very well in Fig. 2 (H alpha). In this image http://cseligman.com/text/atlas/ngc30a.htm (if you scroll down to the large image of NGC 3067) it rather seems like a starburst region(?). Does anybody of you know what this is? Did we really see a "deep-sky object in another deep-sky object", so many light years away?


Clear skies

Robin