Arp 7 and a superimposed star?

[Steve Gottlieb]

While observing last night at a local observing site north of San Francisco with my 18" with, I took a look at Arp 7 (aka MCG -03-23-009 = VV 28 = PGC 24836) and was surprised to clearly see a relatively bright superimposed star, roughly mag 13.5 or perhaps brighter. I had with me Alvin Huey's observing guide for the Arps and he doesn't mention the star with his 22". Nor does Dave Tosteson with a 25" in Jeff Kanipe and Dennis Webb's observing guide to the Arps. At first I thought this might be a supernova, though when I got home this morning I checked the 2MASS image and it clearly shows a superimposed star on the east side of the core. I wonder if others have looked at this galaxy and noted the star? SQM-L readings ranged from 21.37-21.44 last night at this site (Lake Sonoma)

Steve

[RolandosCY]

Will try it tomorrow night, if the weather co-operates...

[RolandosCY]

After spending quite some time preparing finder charts via Megastar for Arp7, I went on to prepare a DSS photo as finder as well, only to note that the declination given by DSS was southern, placing Arp 7 in Hydra instead of Cancer! A check with the Arp Atlas of Canipe and Webb showed that DSS is right, noting that PGC erroneously identifies Arp7 with IC2411, an error carried on to Megastar! Be alert!

[Clear Skies]

In Blue & Red DSS POSS2 images the star is "washed out" by the galaxy's relatively bright core. It does show up nicely in the POSS2 IR image: http://archive.stsci.edu/cgi-bin/dss...e&fov=NONE&v3=
Judging by only the the image I give it mag. 12-13.

Cheers,


Victor

[Steve Gottlieb]

It doesn't appear that bright visually, but I was just surprised that the star wasn't commented on previously by visual observers.