Object of the Week March 10, 2013 - MCG 7-23-19 “Mayall’s Object”

[Uwe Glahn]

ARP 148, VV 32, PGC 33423

Ursa Major

RA
11 03 53
DEC
+40 50 57

Size: 0,6’
Mag: 15.3B (NED)

Type: (Collision Ring) Galaxy Pair

Famous Galaxy Pair which ring-morphology was formed by a collision of two galaxies.

The birthday was during the year 1940 when N.U. Mayall discovered this galaxy pair on a photo plate from the famous 36” Crossley reflector of the Lick Observatory. He described the pair as a “question mark” (http://articles.adsabs.harvard.edu/full/1941PASP...53..187S)

Twenty four years later Burbidge refers more detailed (http://articles.adsabs.harvard.edu/full/1964ApJ...140.1617B) about the object, which was photographed 1961 at the prime focus of the 120” Lick reflector. They first saw details in the ring and the connection between the ring and the cigar shaped part.

493
Lick 120"

Finally the HST showed us the great amount of detail in the shockwave and the main body.

494
HST

My observing notes:
16”, 360x, NELM 6m5+
easy to see with direct vision, small, 1:2 E-W elongated, no ring structure

27”, 586x, NELM 7m0+
bright but small galaxy (pair); 1:2 E-W main body with brighter spots at the ends; W following a very faint, round glow; better defined S edge; no structure within the ring

495
27" Newton, 586x

“GIVE IT A GO AND LET US KNOW”

GOOD LUCK AND GREAT VIEWING!

[Jimi Lowrey]

Uwe, I took a quick look at this unusual cosmic crash last night under less than perfect seeing. I had forgotten just how bright the edge on galaxy was. It looks much brighter than the listed magnitude. I will revisit it again soon when I have better seeing and report back.

[Uwe Glahn]

Hi Jimi,

good to know, I also had the feeling, the the 15,3bmag could perhaps be to faint for the object, when I looked at it with the 16".

I would be very interested how the ring is visible in your scope - is structure within reach?

[FaintFuzzies]

Great object!

I've observed it through Jimi's 48" last year. One of the highlights as I was a little surprised how bright the penetrator was. There was three bright knots along the middle. Anyhow, here are my notes

Arp 148 MCG+7-23-19 and MAC 1103+4050 in Ursa Major

11 03 53.9 +40 51 00 0.5x0.3’ 15.4, 0.4x0.3’ 16.5

48” (488 and 610x) - The penetrator is a 3:1 elongated fairly high surface brightness glow with defined edges. The interesting feature is that it has 3 bright knots along the middle. The ring galaxy is considerably faint and even surface brightness with defined edges.



With my 22", it was not very detailed. My notes are below. Thinking about it, I think I saw only the penetrator, not the ring.

22" f/4.1 reflector @ 255, 305, 377, 458 and 575x (NELM: 6.8, seeing: 4/5, transparency: 4/5)
MAC 1103+4050 required 575x and steady skies to be spotted intermittingly as an extremely faint round patch.
MCG+7-23-19 is a considerably faint, 3:2 elongated patch with no central brightening.
PA = 100º and 20” long.


In light of that, I think I'm going to try again the next time I go out with my 30".

[bearkite]

I observed this with Ursa from a fairly dark site in Western PA this past Friday night (4/5/2013). Seeing was okay. About 3/5 with excellent transparency (SQM 21.32 at the time of observation). Used my new 4.5mm Delos generating 406x. The "Penetrator" (as Alvin called it) was actually quite easy. High surface brightness edge-on in format, but I did not resolve the brightened areas Alvin referred to. Seemed to be a pretty consistent brightness its entire length. No joy on the disc (ring). Even when pushed to 523x. Not sure why that would be, as the images I've seen seem to make it appear almost as bright as the main galaxy.

Any thoughts as to how bright the disc portion really is?

Hope to get another shot at it next month after Josh (Skyraider) gets back from his Jamaica trip (need to put his 25" on this object). Some people just don't have their priorities right. :idontknow:

[Jimi Lowrey]

Using the SDSS photometry the brightest part of the ring is approximately 16.16 V Mag and the faint ring is much fainter. From my experience with the SDSS images when the object is blue looking it is low surface brightness.

571