Object of the Week, April 19 2015 NGC 4731

NGC 4731

Virgo

RA
12 51 00
DEC
-06 23 34

Mag 11.9B

Type
SB(s)cd

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NGC 4731 is one of those galaxies I often ask "why is this galaxy not better known?" It is well placed just a little North of the famous sombrero galaxy (M104) and was discovered by William Herschel on April 25th 1784 (sweep 207) and he recorded “bright, large, little brighter middle, irregular figure, resolvable (mottled)." To me it looks like another cosmic crash galaxy and one that Chip Arp could have added to his Atlas of Peculiar galaxies but missed. I observed this peculiar cosmic crash galaxy twice this week and noted the bright bar in the center and numerous knots in the S shaped arms "What A View"!!!

Attachment 1614

If you are curious as how this unusual galaxy got twisted in this unusual shape you can look 10.4' South of NGC 4731 and you will find the peculiar galaxy NGC 4731A which is at nearly the same redshift as the larger NGC 4731 and is distorted itself and in interaction with the larger galaxy. One day in the distant future the two dancing interacting galaxies will merge into one galaxy.

Attachment 1615

Next time you are looking in South Virgo near the Sombrero be sure to check out these unusual galaxies locked in a cosmic ballet and,


"GIVE IT A GO AND LET US KNOW"

Excellent OOTW. NGC 4731 is quite remarkable in a large scope and fun to revisit it in Jimi's 48-inch a couple of nights ago. Here are my notes

NGC 4731 is an amazing stretched barred spiral with a long, thin central bar oriented NW-SE and long extensions (spiral arms) at the northwest end gently curving west, along with one at the southeast end of the bar extending east. The entire galaxy forms a very distinctive integral sign outline, stretching 5' E-W! The bar is very bright and very elongated, ~4:1 NW-SE, 1.6'x0.4'. The arm on the east side is slightly brighter and longer. It seems to fan out and become patchy near the end. A 15th magnitude star is at or just beyond the tip. The western arm curves gradually to the south and faint haze extends from the arm to the south increasing the total size. A mag 14 star is just south of the bar and a small triangle of fainter stars is north of the bar. A faint, very small HII knot (NGC 4731:[HK83] 21/22) is squeezed between the triangle of stars and the bar.

Very nice OOTW,

I was a little bit surprised that I have a observation and sketch with the 16".

16", 180x, NELM 7m+, Seeing II
Attachment 1617

I revisited the galaxy with the 27" and what a beauty. Mottled and bright bar with two fainter arms to the E and W. I quick and dirty observation shows a brighter knot in the W arm. Also the W arm bend to the S. I saw a arm fragment a little bit separated from the W arm end to the S. The E arm gets much wider to the end. I did not catch the third arm from the bar end to the S.

Nice sketch Uwe I look forward to seeing your 27" drawing.

This is another galaxy I hope to get a view of with my 28 inch in the next week or so. Jimi, Steve and I had a great look a couple weeks ago with Jimi's 48 inch:

Attachment 1645 Attachment 1646

This was on our first night in Ft. Davis and I was really tired and didn't take any notes, but the sketch captures the essence of the view. Amazing.