ASTRO: Arp 140

I thought I'd posted this one long ago. It was taken September 19, 2009
UT. I processed it in April but apparently then forgot about it. I
can't find I posted it. Hope I'm not duplicating but after a long check
I don't think I am. Since I used a new (to me) processing technique to
get rid of satellites (with only 4 subs a rejection stack routine isn't
useful. More on that in the text below from last April.

Arp 140 is a pair of interacting galaxies, NGC 274 and NGC 275 right to
left. They are 65 million light years distant and in the constellation
of Cetus. Arp classed them under; material emanating from elliptical
galaxies. A category that makes little sense to me. M87 has a nice jet
and would seem to fit but but its under galaxies with jets which is more
accurate though its the black hole not the galaxy itself that is the
cause of the jet. Other than jets what can an elliptical, or its black
hole, emanate? All galaxies I've imaged so far in this category involve
a highly distorted galaxies, #142 through #145. All appear to be due to
interacting galaxies. Arp 140 appears to fall into this pattern. Or
does it? In the other cases both the elliptical and the spiral are
distorted. Usually the spiral is considerably more distorted which
isn't surprising. But both show distortion. Not in this case. Here
the elliptical, NGC 274, really an S0 galaxy not elliptical, seems
little distorted though it is classed a being peculiar. But its
companion, at the same red shift distance, NGC 275 is highly distorted
and generating new stars like crazy. This seems hard to explain. It's
likely they are much farther apart than their nearly equal red shift
indicates with probably the distorted spiral being closer to us. I say
this because its blue color overlays some of the golden S0 galaxy. The
S0's higher density may be helping keep it from distorting very much.
While some theories say an S0 is the result of a galaxy merger it
appears NGC 274 was already S0 long before this encounter. That doesn't
mean it didn't have a previous one billions of years earlier that
created it. But now look really closly at the 2x enlargement. There
does appear to be a very faint linear feature coming from the S0 pointed
to the east northeast. There seems to be a faint tidal spray on the
entire east side of the galaxy compared to the western side as well. So
maybe Arp was right after all though I see no hint of the feature in
Arp's image. I need to take a much deeper image though that is likely
impossible due to satellite traffic. This pair is right in the
geostationary belt as seen from my latitude.

NGC 275 does appear highly disturbed by the encounter. It is classed as
SB(rs)cd pec. Peculiar it certainly is! It's spiral structure is
hardly recognizable. The core is almost gone but does have a typical
orange color. The galaxy is dominated by its many massive star forming
HII regions.

Due to all the geostationary satellites that were seen in this image I
had to do some fancy processing, well fancy for me, to eliminate them
from hiding the galaxies. Many of the trails were atop other trails
making it unlikely that even if I had enough sub frames I could use any
normal noise rejection combine successfully. But with only 4 frames
that wasn't an option to even try. Fortunately 2 frames had no bright
satellites crossing the pair. The other two had a bunch. So I
processed all 4 as well as just the two "good" ones. The latter was
pretty noisy having too little time to make a good image. What I did
was to process it to match the light levels of the 4 frame image but
then applied stronger than normal noise reduction. I then copied just
the part with the galaxies and pasted it into the full image brightening
it slightly. This got rid of the satellites but left less detail in the
galaxies. I then merged the two using "Darken" as the blend option.
This prevented the satellites from showing but returned the detail to
the galaxy since the galaxies were dimmer in the 4 frame image. I
didn't do this with the full image as doing so would have wiped out the
three asteroids as well as the satellites and played havoc with the
brightness level of the stars. I tried it but didn't like the result.
So I just used this for the area in and around Arp 140.

There are three asteroids in the image. The brightest is southeast of
Arp 140, a bit under one third of the way to the lower left corner. It
is (80188) 1999 VC37 at an estimated magnitude of 18.1 but appears a bit
dimmer to me. Almost as bright is (49774) 1999 WT9 straight south of
(49774) 1999 WT9Arp 140 about half way to the bottom. It too has an
estimated magnitude of 18.1 but is fainter than than the first one in my
image. Fainter still is the one near the lower left corner by a
slightly orange star. It is (186173) 2001 UZ155 at an estimated
magnitude of 19.1. That appears about right. The transparency this
night was poor limiting my ability to go faint. Asteroids are common
only 8 degrees from the ecliptic as this object is.

The Hubble Legacy site had 4 frames of mostly NGC 275. Two in the near
IR and two marked "detection". Exposure time was only 640 seconds so
they are noisy. I made an image from the detection frames that is
attached. Due to high noise it has been reduced greatly in size. The
field is out of the Sloan survey coverage.

Arp has something entering his image as well. The angle is wrong (at a
right angle) for a belt asteroid so it may be an early high inclination
satellite trail.

Arp's image:
http://nedwww.ipac.caltech.edu/level...ig_arp140.jpeg

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Rick