Arp 3 Another apparently lost on the hard drive for years

Arp 3, MCG-01-57-016, is a low surface brightness spiral, which is also where Arp put it in his catalog. It's located in Aquarius a bit southeast of the "Water Jug". Red shift data puts it about 60 million light years distant. Using the Tully-Fisher method of determining galaxy distance based on its brightness and rate of rotation one team says it is about 75 million light years distant. That seems too far. In fact the 60 million light years sounds too far to me. Hubble should find a few Cephieds in it but it hasn't looked at it. NED classes it as SA(s)m. It looks rather distorted with a large faint loop to the south. I did a NED search with a default radius of 100 arc minutes looking for any galaxy with a similar red shift but nothing was found. This may just be due to this area being so poorly surveyed. In any case I couldn't find another galaxy to blame for this distortion. It may be due to something it ate leaving only the plume as evidence of the crime.

There are many fuzzy spots in this galaxy besides a few stars. The APMUKS catalog lists them as separate galaxies. But this is an automated plate solved catalog which is rather "dumb" just logging the position of galaxy like objects. I think it quite likely, given that there are few outside the galaxy, that these are star clusters within the galaxy. All are rather blue as such clusters usually are while small distant galaxies would tend toward the red end of the spectrum.

There's little on this entire field. Probably due to its location in a rather obscured area of the sky. No red shift data is present for the entire field. Nearly all the galaxies are either from the APMUKS catalog or are IR strong galaxies from the 2MASX catalog.

I did pick up two asteroids in the image. The obvious one below Arp 3 is (41031) 1999 UA47 at an estimated magnitude of 18.4. The fainter one is 8.5 minutes of arc east and a bit over one minute south. It is (140880) 2001 VL20 at an estimated magnitude 20. Its tilted up with the high end to the east just a bit more than (41031) 1999 UA47. Thanks to its motion it is rather faint and difficult to spot. I didn't notice it until I was looking up the other and was told it was in the field. A third one is just out of the field to the south.

One of the more interesting field galaxies is to the southwest of Arp 3 two thirds of the way to the lower right corner. It is just to the upper right of a rather bright orange star. I was wondering if it was a double galaxy or just had a core well to the southeast. Unfortunately NED show no galaxies within 2 minutes of its location. Another blue galaxy that was missed even by the APMUKS catalog. Or is it two galaxies? I still don't know.

Arp's image:
http://nedwww.ipac.caltech.edu/level.../big_arp3.jpeg

14" LX200R @ f/10, L=8x10' R=3x10'x3 GB=2x10'x3, STL-11000XM, Paramount ME

Green and blue had their last frames lost due to clouds. This made the galaxy's color a bit noisier than I'd have liked. Somehow I never got back to taking those missing frames.

Rick

Rick,

the "long arm" indeed looks suspicious for a lonely galaxy.
Guide 9 has it as PGC 0069293, where "PGC" at least sounds more familiar than "MCG".

At the time I wrote that NED didn't list PGC galaxies and used MCG for their main not NGC/IC objects like this one. Only recently did they start listing PGC but as far down the list. When I asked why they said the PGC had too many errors compared to the MCG. It stands for Morphological Catalogue of Galaxies which also tends to have more info on an entry than the PGC. But The Sky also prefers PGC same as Guide 9.

Rick

Originally Posted by slilge

Rick,

the "long arm" indeed looks suspicious for a lonely galaxy.
Guide 9 has it as PGC 0069293, where "PGC" at least sounds more familiar than "MCG".