Object name: HCG069-IC4343-IC4344-IC4345-IC4346-IC4348-IC4349-FGC0195A

Designation(s): HCG069-IC4343-IC4344-IC4345-IC4346-IC4348-IC4349-FGC0195A,

HGC 69 is a group of 4 galaxies in western Bootes about 400 million light-years distant. Hickson groups, of which there are 100, must meet 4 requirements.

1. There must be 4 galaxies or more with a similar brightness that are brighter than 26.0 surface brightness per square second of arc.

2. The group must be isolated, not a small section of a larger group or cluster.

3. The group has to be so compact their relative sizes are similar to the distance between galaxies themselves.

Oddly, HCG 69 appears to break rule 2. There are a lot of galaxies, larger and smaller in angular size, in the image that are all (including HCG 69) part of a much larger group of galaxies. Note however Hickson doesn\'t say they all have to be at a similar distance. At the time of his listing, distances weren\'t all that well known. In fact, the first compact group known, Stephan\'s Quintet (HGC 92), has one member that\'s much closer than the others. All Hickson required was they visually appear likely to be at the same distance. In the case of HCG 69, they really are.

They are PGC 49499, 49502, 49505 and 59507. Hickson assumed many of his groups would show gravitational interaction when studied in detail. It\'s quite obvious from just my image that HCG 69A, PGC 49502, is highly distorted. It and HCG 69C, PGC 49505, are passive nucleus galaxies. A definition of them I found reads: \"Passive nuclei (PAS) are typically red, contain exclusively old stars, with no star formation activity: their spectra show both H and [NII] in absorption. Thus the cores are red and dead though some I\'ve found have jets so not totally dead. No jet is seen in these, however. Also, the entire galaxy need not be dead. HCG 69A has a blue star plume to the southwest indicating it is still forming new stars in that part while much of the rest is rather red. Thanks to this plume it is a huge galaxy which I measure at 194,000 light-years across. Note too that it has a very faint plume going north and a bit easy that goes past PGC 49499. This may indicate the path of yet a 5th galaxy it ate over hundreds of millions of years ago.

Many of the other galaxies associated with the same group as HGC 69 are also rather red and dead with a few exceptions such as ASK 538092.0 to the north of HGC 69 which is quite blue and very actively forming stars throughout as is LEDA 1723672 to the west.

There are 6 IC galaxies in the image 4343, 4344, 4345, 4346, 4348 and 4349. Redshift puts IC 4348 70 or so million light-years further away so it may not be related. The rest, however, are certainly members of the group that contains HCG 69. All 6 were discovered by Stephane Javelle on June 15, 1895.

There\'s an interesting pair of possibly interacting galaxies to the east-southeast of HCG 69. I found a redshift for only the southern galaxy. So are they interacting or is one well in front of the other so no interaction is possible? Wish I knew.

A quasar to the southeast is listed as having Damped Lyman Alpha emission. For what this means, see: https://en.wikipedia.org/wiki/Damped_Lyman-alpha_system

The stars are a bit flat on the bottom due to tube currents. Normally I let the scope cool to avoid these for an hour before imaging but this night was threatening rain so I didn\'t open the roof when suddenly the skies cleared with just enough time for one object. That left no time for cooling. I hoped the drizzle had helped cool the scope to ambient but this image showed that didn\'t happen.

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