Following from the OOTD on Saturday 21st of July, I sent these objects to Daniel Darg at Oxford for his expert opinion.
See also OOTD for 6th September 2008
All that follows is from Daniel (formatted by me):
Firstly, there are some tricks people should know about if they want to make really informed decisions about these mergers. The first trick is this:
1) If you want to have information about an entity next to your galaxy that might or might not be a mergering galaxy, you can usually find it straight away by plugging the object id of your galaxy into the SDSS page and then changing the very last digit + or - a few. Normally this will put you right on top of the object.
... then try changing the last digit to,say, 1:587722982279938051
... and voila! you are centred on your object in question. There are then two major questions to ask to help you decide whther this is a merging galaxy.
i) Does it have a redshift? If so, compare it with the GZoo object's redshift to see if they are similar. If theyre different by more than ~0.005 then its probably a projection (though this number depends on certain things so you need to be careful).
Often these extra objects will not have a redshift. The next question thats often useful to ask is whether SDSS reckons if this is a star or not. If you go from the above webpage and click the left hand link called 'PhotoTag' then you'll see a bunch of data relating to the photometry of this SDSS object. The one were most interested is an integer quantity called 'type.' SDSS photometry can tell whether or not an object is 'point-like' which is normally what a star looks like or 'extended.' On this basis it can decide if the object is a star or a galaxy. If it is a galaxy, itll return type=3 and if it thinks its a star then itll return type=6. When you do this with the example object id I used above, you get a type = 6 for the closeby object so its almost certainly a star! (Ive found this tag to be very reliable).
As for the list, here is what I would say by applying these tricks:
Probably a merger. Appears to be distortion in the shape of the central object.
Def. a star as revealed by the profile of surface brightness (very constant with radius) and phototag type=6
Probably a minor merger. Looks like there's a small (second) core at the bottom and slight disruption to the top right
These are defiantly interacting (you can see some ejected material in the wider view). Whther or not they will completely merge is impossible to say for sure though my guess is they would. It should be counted as merger in any case due to the tidal interaction.
These are defiantly merging. Im surprised this one is in question. They are nicely blended together and there likes like theres some disturbed/ejected material to the top right. The bottom galaxy also has spectra (object 587722982815694957 which I found by adding/subtracting to the last digit) and its redshift is 0.071 which is very similar to the upper objects redshift 0.072. So theyre not a projection.
This is again a star overlapping a non-merging galaxy. the stars object id is 587724197469028507 and when you look at the phototag, it has type=6. its a bit hard to tell, butId say the surface brightnes profile does look starlike as well.
This system is clearly perturbed and, to be honest, Im in two minds whether or not to call this a merger. It could be that a galaxy whizzed past it ages ago and has dissapeared or that it was the result of a minor merger. In general, Id lump these sorts of things in.
This is defiantly a merger. Its significantly perturned and there looks to be ejected material way up at top of the image (if you zoom out a little).
This is most certainly a star. You shouldnt need to look at the phototag (which if you want to check is type=6 for 587724231568916582) to see that the surface brightness profile is way too constant to be the product of billions of red stars all packed together in a superdense and constant distribution.