DescriptionImages

Object name: NGC5674

Designation(s): NGC5674, NGC5679, ARP274, UGC09385,

Back in 2010, I imaged Arp 274 though didn't get it processed until May of 2011. I centered on Arp 274 not realizing a companion to these was just outside the field of view and actually more interesting. This image rectifies that omission by framing the field as I should have back in 2011. It also corrects a few mistakes I made in the original post and its annotated image.

Arp 274 is a galaxy triplet though Arp seems most interested in the two on the left saying the little galaxy has perturbed the eastern arm of the big galaxy. The middle galaxy's eastern arm does have a bulge that points to the little galaxy but from what we now know of galaxy interactions that isn't the type of distortion we'd expect from an interaction. Redshift data now indicates the middle galaxy is likely 40 to 50 million light-years beyond the other two. While NED had no redshift on the little galaxy on the east several papers do show a measured redshift that's almost identical to the western galaxy and nearly 1000 kps different from the center one showing they are unlikely true companions. The middle galaxy apparently is just a background galaxy photobombing the other two. Hence a nice field but otherwise uninteresting. The HST has more on this at: http://www.spacetelescope.org/images/ann0904a/ .

For this image, NGC 5674 was my primary target. It is really strange. The inner core region looks much like the many "Saturn-like" galaxies I've imaged but the southern ansa has an arm coming off it that bends up to the north and west to either join or possibly become a huge ring that nearly encircles the Saturn-like core. Much like NGC 1954 I posted last just, it seems made up of parts taken from two very different galaxies.

This field is located in northwestern Virgo. The two probably related galaxies in Arp 274 and NGC 5674 are about 360 million light-years distant. This means NGC 5674 is a very large galaxy with a diameter of about 140,000 light-years including the plume on the northeastern side. The western spiral of Arp 274 is a bit over 100,000 light-years across assuming the north pointing blob between the two large galaxies is part of the western one. The central one is about 110,000 light-years across assuming it is 400 million light-years distant. It is obviously a more massive galaxy than the western one but its arms are less pulled out giving it a slightly smaller angular length even though its bulk makes it seem much larger than it measures. The dinky third member is less than 30,000 light-years across.

NGC 5674 was discovered by William Herschel on May 12, 1793 but is not on either Herschel 400 list. NGC 5679 was also found by William Herschel but not the same night. It was discovered months earlier on February 12, 1793. It is certain he found the center galaxy but I can't say if he saw the western galaxy or not. It might have been too faint. Like NGC 5674 it isn't on either Herschel 400 list.

Further to the southeast is the very low surface brightness galaxy UGC 9385. At only 85 million light-years it is much closer but also much fainter. It is about 60,000 light-years across its two very widely spread diffuse arms. Even combining its image using data from both nights 4 years apart, it is too faint to get a good measurement on it. While NED classifies it as an irregular galaxy it seems to have a barred spiral structure to my eye. The arms seem spread unequally with the northern one further from the core than the southern and less well defined as well.

The image contains several candidate quasars (CQ) in the annotated image. NED also listed several dozen ELG's (Emission Line Galaxies). While most show in my image they are very faint. They are likely very active galaxies with super bright cores to be seen at the distances they are. I have to wonder if some are almost quasar bright. I've only marked two on the image one with a look back distance of 7.21 billion light-years and another even further at 8.50 billion light-years and a z of 1.19. All are starlike showing no hint of "fuzz" in my image. The latter having a magnitude of 22.7 per NED so these are very faint objects. I wish I knew more about what they might be.

14" LX200R @ f/10, L=4x10' RGB=2x10' STL-11000XM, Paramount ME