NGC 5364

NGC 5360, 5363 and 5367 are a trio of non interacting galaxies in Virgo
and members of the famous Virgo Galaxy Cluster about 60 million
light-years from us. I'll tackle them in reverse order.

NGC 5364 is a nice spiral galaxy which redshift puts at 70 million
light-years but other estimates say more like 63 million light-years
which seems more reasonable. NED calls it SA(RS)bc pec with HII. The
NGC project's more simple classification is Sbc/P. They are in
agreement that it is peculiar. It has an rather diffuse inner spiral
structure that ends with a nice ring. Two major arms spiral off this
ring, each making slightly more than a complete 360 degree trip around
the galaxy. Most of the HII regions are small but one large one is
obvious in my image with faint hints of pink throughout the rings. More
would likely be seen if I added H alpha data but I've not taken any. At
63 million light-years, its angular size indicates it is about 125,000
light-years across. One of the larger spirals in the Virgo Cluster.

NGC 5363 is a strange galaxy that NED calls I0? and the NGC project
describes as S0-a. I tend to agree with the NGC Project as it has some
interesting dust structures in my image I'd expect in a S0 galaxy with
some Sa traits. It has a LINER core so its black hole is apparently
finding something to chow down on. A star right near the core doesn't
help with resolving that region of the galaxy. Redshift puts it about
65 million light-years away. Several papers refer to a short, fine dust
lane running along its minor axis. The only dust I can resolve is along
the major axis. As elliptical like galaxies go, this is a more
interesting one. Measuring the very outer halo of this galaxy and
assuming the 65 million light-year distance it is also about 125,000
light years across its major axis. If it is really somewhat elliptical
in shape and that isn't exactly face on then it would be even larger.
Just the inner regions where we see the dust lanes are 70 million
light-years across.

NGC 5360 is a much smaller galaxy that NED says is I0 same as NGC 5363
but without the question mark. The NGC project disagrees calling it
SB0-a. I'm not sure what to make of that. Redshift puts it 67 million
light-years away. This seems a bit too big. It likely is closer but
moving away right now in its orbit about the cluster making it appear
further away than it really is. Though the only non redshift
measurement I found puts it almost 75 million light-years distant.
Assuming the shorter distance it is about 32,500 light-years across.

I find it interesting that NGC 5363 is quite reddened, NGC 5360 white
and NGC 5364 rather blue in color. Sort of a patriotic image -- Red,
White and Blue.

The fourth NGC galaxy at the upper left of my image. It lies far beyond
the Virgo Cluster at over a half billion light-years distant. NED lists
it as a compact galaxy with star formation. No other classification is
given. The NGC Project also says "Compact" but makes no reference to
star formation.

I expected to find quite a few dwarf or at least small members of the
Virgo Cluster in the image as such galaxies far outnumber the major
galaxies in the cluster. But only 4 were seen. Three along the right
edge and one near the left edge. Only the latter had a designation
beyond that of its coordinates. IT is CGCG 046-013 with a redshift
distance of 83 million light-years. So it could lie beyond the cluster
if that is a true distance indicator.

In preparing the annotated image I ran into some issues I'd not come
across before. In some cases NED lists the redshift distance as
questionable but doesn't say in what way or by how much. For those I've
put a question mark after the distance which is based on this
questionable redshift figure. Then I ran into some galaxies at
distances far beyond those of the quasars in the image or even quasar
candidates (UvES). One had a redshift putting it 11.39 billion
light-years distant with a z of well over 2. No way I can see a galaxy
at that distance. But NED lists these as galaxies rather than quasars
or quasar candidates nor does it indicated any issues with the redshift
value. These are listed G? in the annotated image. NED listed many IR
galaxies that are bright enough to show in my image if their visual
brightness was similar. Apparently they are far fainter in visual light
as I couldn't find any of these, even those 4 magnitudes brighter than
my visual limit. After finding the first dozen or so were beyond my
reach I didn't investigate the rest unless it was listed at magnitude 18
or brighter. None of these were seen in my image however so even that
was a waste of time. Some of the galaxies were very faint. While
visible in the uncompressed TIFF image I used to make the annotated
image some are extremely faint in the compressed JPG image so if you
don't find them that's the reason. Though all I checked in the JPG
image do show if you blow up the image a couple times.

As usual I ran across several galaxies not in NED at all. Again this
was only because I double checked to be sure I hadn't missed them wading
through all the invisible IR objects. Since I did this only with a few
that interested me I again suspect quite a few more were also overlooked
by the automatic software that picks this data out of the Sloan Survey data.

14" LX200R @ f/10, L=5x10' RGB=2x10', STL-11000XM, Paramount ME

Rick
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Prefix is correct. Domain is arvig dot net

After looking at the net version I decided I held back the core of NGC
5364 too much. I had to hold it back from a full stretch or it burned
out the core region. I did so to too great an extent making it rather
flat. Here's a version with more pop due to less reduction of the
stretch of the core region of the spiral.

Rick


--
Prefix is correct. Domain is arvig dot net