ASTRO: Gravitationally lensed galaxies in Abell 2218

I've attached my image with some of the arcs identified and for laughs
Hubble's version. It may have the advantage of a bigger mirror, no
atmosphere and thus higher resolution but I do have at least a $1.5
billion dollar cost advantage! The image is enlarged to 0.25" of arc
per pixel.

Arc A, galaxy 362 and galaxy 468 are all the SAME galaxy. It is located
some 10.7 billion light years from us and 8.6 billion light years beyond
the lensing cluster Abell 2218. Arc A has a magnitude of 22.35. Arc
362 is listed by NED as magnitude 24.52 while 468 is magnitude 23.74
Image 468 is virtually undistorted but even Hubble can't see much detail
in it. Arc A, once deconvolved shows more detail. This is a very
interesting galaxy. You can read more about it at:
http://arxiv.org/PS_cache/astro-ph/p.../9802230v1.pdf
This is a PDF file so you need a PDF reader to view it.
The idea I could see things this faint is far beyond my expectations
when I designed the observatory. Note the article says the true
magnitude of the galaxy is 14.5 times fainter than this. So I'm only
seeing it thanks to one of the universe's largest telescopes, one that
is millions of light years in aperture but with a rather imperfect lens.

Arc H is rather bright in Hubble's image but my CCD is rather
insensitive to its red color making it harder for me to pick up. It is
listed as being 6.1 billion light years from us, 4 beyond the imaging
cluster and is listed at magnitude 24.4 which seems low to me.

Arc 323 is listed at 22.2 magnitude and is only 4.1 million light years
away so it is about as far from the lensing cluster as we are from the
cluster. It may be the brightest arc but it is rather lost in the
galaxy at my resolution making it hard to see in my image.

Arc L is interesting in that it is two arcs if you look closely at the
Hubble image. A blue arc and a rather small red blob near one end. It
all merges together in my "low resolution" image. Anyway the blue arc
is a quasar that was located in just the right spot to be highly
distorted into a blue arc by the lens yet the galaxy around it is nearly
undistorted, just backwards from what I'd expect. Redshift data shows
both to be at the same distance of 7.6 billion light years and the
combination shines at magnitude 23.4.

The remaining object is galaxy 308. It too seems rather undistorted.
It is magnitude 23.39 and is 5.6 billion light years away. If you
compare the two images other lensed galaxies can be seen as well but I
was unable to get much info on them so I'll stop here.

The enormous elliptical galaxy that anchors the cluster isn't listed
anyplace I can find! The only bright galaxy NED or SIMBAD list near
that location is LEDA 140648. That is the small round elliptical about
8" of arc below the main galaxy in my shot. In any case the cluster is
listed at 2.07 billion light years.

If by chance the seeing and transparency needed ever return with it high
in the sky like this I'll be trying for more data. But at once in 3
years, don't hold your breath.

Sorry about the satellites. Sigma reject was slightly noisier than the
add combine I used so I couldn't process them out that way and my
cloning abilities were all too obvious so you will have to ignore them.

14" LX200R @ f/10, L=6x20' binned 1x1, RGB=2x20' binned 2x2,
STL-11000XM, Paramount ME

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

that's one of my all time challenge objects: one that I said someday i will
seriously attempt again

It is a difficult one for su all about good seeing and good transparency.
Right now what with the fires all over the state we have one of the two at
best :-(

That's probably the best amateur image of it that I have seen.

My 18" set up at the ranch on a good night would be a good match for it but
that's a ways away right now

rdc



"Rick Johnson" wrote in message
om...
I've attached my image with some of the arcs identified and for laughs
Hubble's version. It may have the advantage of a bigger mirror, no
atmosphere and thus higher resolution but I do have at least a $1.5
billion dollar cost advantage! The image is enlarged to 0.25" of arc
per pixel.

Arc A, galaxy 362 and galaxy 468 are all the SAME galaxy. It is located
some 10.7 billion light years from us and 8.6 billion light years beyond
the lensing cluster Abell 2218. Arc A has a magnitude of 22.35. Arc
362 is listed by NED as magnitude 24.52 while 468 is magnitude 23.74
Image 468 is virtually undistorted but even Hubble can't see much detail
in it. Arc A, once deconvolved shows more detail. This is a very
interesting galaxy. You can read more about it at:
http://arxiv.org/PS_cache/astro-ph/p.../9802230v1.pdf
This is a PDF file so you need a PDF reader to view it.
The idea I could see things this faint is far beyond my expectations
when I designed the observatory. Note the article says the true
magnitude of the galaxy is 14.5 times fainter than this. So I'm only
seeing it thanks to one of the universe's largest telescopes, one that
is millions of light years in aperture but with a rather imperfect lens.

Arc H is rather bright in Hubble's image but my CCD is rather
insensitive to its red color making it harder for me to pick up. It is
listed as being 6.1 billion light years from us, 4 beyond the imaging
cluster and is listed at magnitude 24.4 which seems low to me.

Arc 323 is listed at 22.2 magnitude and is only 4.1 million light years
away so it is about as far from the lensing cluster as we are from the
cluster. It may be the brightest arc but it is rather lost in the
galaxy at my resolution making it hard to see in my image.

Arc L is interesting in that it is two arcs if you look closely at the
Hubble image. A blue arc and a rather small red blob near one end. It
all merges together in my "low resolution" image. Anyway the blue arc
is a quasar that was located in just the right spot to be highly
distorted into a blue arc by the lens yet the galaxy around it is nearly
undistorted, just backwards from what I'd expect. Redshift data shows
both to be at the same distance of 7.6 billion light years and the
combination shines at magnitude 23.4.

The remaining object is galaxy 308. It too seems rather undistorted.
It is magnitude 23.39 and is 5.6 billion light years away. If you
compare the two images other lensed galaxies can be seen as well but I
was unable to get much info on them so I'll stop here.

The enormous elliptical galaxy that anchors the cluster isn't listed
anyplace I can find! The only bright galaxy NED or SIMBAD list near
that location is LEDA 140648. That is the small round elliptical about
8" of arc below the main galaxy in my shot. In any case the cluster is
listed at 2.07 billion light years.

If by chance the seeing and transparency needed ever return with it high
in the sky like this I'll be trying for more data. But at once in 3
years, don't hold your breath.

Sorry about the satellites. Sigma reject was slightly noisier than the
add combine I used so I couldn't process them out that way and my
cloning abilities were all too obvious so you will have to ignore them.

14" LX200R @ f/10, L=6x20' binned 1x1, RGB=2x20' binned 2x2,
STL-11000XM, Paramount ME

Rick

--
Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".

magnificent!

--
martijn
www.xs4all.nl/~martlian

Another one that missed my server.

Great result Rick. My limit here in the city is about mag 20.5, so I don't
even have to try this one.

Stefan