ASTRO: NGC 6015 and a cometary galaxy

NGC 6015 is a multi-armed, warped spiral galaxy in Draco, south of the
bowl of the Little Dipper. It's distance is hard to pin down. Too
close for redshift to be reliable other methods need be used.
Tully-Fisher measurements range from about 50 million light-years to 66
million light-years though most cluster toward the lower estimate, say
55 million light-years. Oddly the highest and lowest measurements have
the smallest error bar yet neither includes the other. They are just
too far apart.

Papers on this galaxy are also somewhat in disagreement, one finding a
strong ring structure and another saying they couldn't find one. Though
that one looked at CO radio frequencies while the one finding a ring
used a wider range of frequencies. That paper goes into a lot of detail
on this galaxy. It's abstract is at
http://adsabs.harvard.edu/abs/1997A%26A...321..754V with a link to the
free full article. The galaxy has no obvious central bulge.

The smudge of a galaxy off the eastern edge of the galaxy is SDSS
J155136.52+621728.6. NED has no redshift data for it. I'd think it
likely related to NGC 6015 but that is only a guess until more is known
about it. To the east of NGC 6015 is a very odd galaxy. It looks just
like a comet! Since it shows up on the POSS plates dating back to the
1950's it is one slow comet! I would love to tell you about it. NED
says it doesn't exist! It shows nothing at the position. NED does show
the reddish spherical galaxy above it as the IR source 2MASXi
J1552150+621928/SDSS J155215.07+621927.8. Between the IR galaxy and the
comet-like one NED shows a 23rd magnitude point source galaxy which on
the Sloan plate shows up as a bright green hot pixel but they show
nothing for the position of the comet-like galaxy. Did they fall for it
being a comet? I can't fathom any other reason for leaving it out. The
Sky 6 shows it as PGC 2634580 and 17.8 magnitude.

While this field is covered by the Sloan survey and NED shows at least
3000 galaxies in the field ONLY ONE has any redshift data. That is NGC
6015 which is too close for it to be very useful. The image is full of
interesting galaxy groups and clusters. Some of these did have redshift
data. I was half done with the annotated image when I realized I wasn't
picking up any galaxies. So I finished it, skimpy as it is.

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

Rick

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