Archive for April 2021

NGC 3226 and NGC 3227, Galaxies in Leo: April 2021 Observer’s Challenge Report #147

April 16, 2021

MONTHLY OBSERVER’S CHALLENGE

Compiled by:

Roger Ivester, North Carolina

&

Sue French, New York

April 2021

Report #147

NGC 3226 & NGC 3227, Galaxies in Leo

Sharing Observations and Bringing Amateur Astronomers Together

This month’s target

William Herschel discovered this interacting galaxy pair on 15 February 1784 with his 18.7-inch speculum-metal reflector. His hand-written journal of the discovery reads: “Two nebulae almost close together. Perhaps 1½ or 2′ asunder, they are pretty considerable in size, and of a roundish form; but not cometic; they are very faint.” He also notes that on this night he first used: “A new, large object Speculum. It is very bright but not quite as distinct as my first, I shall however use it all the night.”

Together known as Arp 94, NGC 3226 and NGC 3227 are wedded in a gravitational dance 47.2 ± 0.2 million light-years away from us. Their complex dance has spawned a remarkable array of tidal tails as well as one tidal dwarf galaxy — a gravitationally bound condensation of gas and stars formed during the repeated encounters of the two parent galaxies.

The most recent journal paper on this captivating system can be perused here: https://www.aanda.org/articles/aa/full_html/2021/01/aa38955-20/aa38955-20.html

Observer’s Challenge Complete Report:

April 2021 OBSERVERS CHALLENGE _NGC 3226_NGC 3227

NGC 3226-3227: Interacting galaxy pair in Leo 

Date: March 2021

Telescope: 10-inch f/4.5 reflector 

Sketch Magnification: 114x

Field of View: 0.52º 

NGC 3227: Fairly bright, and easy to locate and see even at low magnification.  At 114x, elongated, oriented NW-SE, brighter central region, but subtle.  I first observed this galaxy pair and made my first sketch on April 14th 1993.   

NGC 3226: Much smaller and a fainter than NGC 3227, mostly round, but with a very slight elongation, NNE-WSW.  At 190x, and with averted vision, a stellar nucleus is visible.  Roger Ivester

Sue French: Observer from New York

Through my 130-mm refractor at 23×, I see a moderately faint glow at the position of the interacting pair NGC 3226 and NGC 3227. At 63× it becomes evident that two galaxies dwell here. Although their halos blend together, each harbors a small, distinct, brighter center. NGC 3227 is the brighter and larger galaxy of the pair, its oval façade leans east-southeast. Precariously perched on NGC 3227’s north-northeastern tip, NGC 3226 is wrapped in a halo that tips northeast.

NGC 3222 makes an appearance in the field of view 117×, 13′ west of the interacting duo. This little galaxy appears very dim and holds a weakly glowing, starlike nucleus. A 14th-magnitude star winks in and out of view near the galaxy’s SW×W edge. At this magnification, NGC 3226 grows brighter toward the center, while NGC 3227 displays an oval core with a prominent stellar nucleus. I estimate combined length of the pair to be about 41⁄2′.S