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ASTRO: IC 277



 
 
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  #1  
Old December 6th 12, 08:18 AM posted to alt.binaries.pictures.astro
Rick Johnson[_2_]
external usenet poster
 
Posts: 3,085
Default ASTRO: IC 277

IC 277 is a galaxy with a large plume suggested to me by Sakib Rasool.
It is about 120 million light-years distant in the constellation of
Cetus. Why it has such a huge plume is the issue. It might be due to a
nearby galaxy. The one to the north is often cited as being related.
Problem is there's no redshift info on it and it doesn't appear
distorted. Usually such a small galaxy would be torn apart by the far
larger one not the other way around. That's the problem with the others
nearby as well. Either the culprit has moved on or this is the result
of a merger. I find nothing in the literature to help.

While the Sloan survey has images of this area, none of the data is in
NED. That left only two other objects in the field for which NED had
distance data. I wasn't going to prepare an annotated image but then
looked at these two. They are both listed as quasars. One of which is
so different from what I normally think of as being a quasar I decided
it was worth covering. This is [HB89] 0257+024/US3498. NED lists it as
being a galaxy, a quasar, a blue star and a UvES object. Wow, what an
overachiever this guy is. The distance listed is only 1.45 billion
light-years. Super close for a quasar. In my image it looks like a
quite normal spherical reddish galaxy. It looks the same on the Sloan
image. Yet this is what a note at NED has to say about it:
"The host of this radio-quiet quasar is dominated by a disc component
with a best-fitting scalelength of r_1/2_ = 10 kpc (Fig. 1n). The
model-subtracted image in Fig. A14 shows a ring of emission at ~4 arcsec
radius. Also revealed is substantial residual flux in the inner ~2
arcsec where the host galaxy is bulge-dominated. This feature can also
be clearly seen in the luminosity profile shown in Fig. 1(n). As a
result of the central bulge, the variable-beta model chooses a
substantially lower value of beta (0.75), and offers a significantly
better {chi}^2^ fit than a pure exponential disc. Nevertheless, this
transpires to be the most disc-dominated host galaxy in the quasar
sample observed to date."

The full paper can be seen at:
http://adsabs.harvard.edu/cgi-bin/bi...NRAS.308..377M though
I've reproduced about all it has on this particular one. Since it was
done with HST data I did look that up and have included a quick and
dirty process of the mono HST image of this galaxy. Shows what appears
to be a Sa tightly wound spiral with a very bright core compared to the
disk. Arms are of very low contrast to the image is done in the red
region of the spectrum 675nm so would likely suppress the disk region
and lower arm contrast. Note the really strange galaxy to the northwest
in the HST image. Seems strangeness is rather common if you look deep
enough.

The other quasar is at a more common distance for a quasar. No galaxy
is seen, just a very blue star-like object. NED lists 4 objects as UvES
from the US catalog (USher Faint Blue Stars). Often these turn out to
be quasars. Until the Sloan data is published there's no way to tell if
they are just blue stars or quasars. I've labeled them on the annotated
image. As usual, if no distance data is available I use a question mark
where it would normally appear.

I saw a blue frame was lost to clouds and replaced it but missed that a
green one was also lost to clouds so had to process it with one less
green frame than normal. Also I thought two luminance frames were
unusable due to clouds so retook two. Turned out it was slightly better
using all 6.

14 LX200R @ f/10, L=6x10 RB=2x10 G=1x10, STL-11000XM, Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

Attached Thumbnails
Click image for larger version

Name:	IC277L6X10RB2X10G1X10.JPG
Views:	223
Size:	277.9 KB
ID:	4386  Click image for larger version

Name:	IC277L6X10RB2X10G1X10-ID.JPG
Views:	101
Size:	143.8 KB
ID:	4387  Click image for larger version

Name:	IC277L6X10RB2X10G1X10CROP150.JPG
Views:	80
Size:	132.1 KB
ID:	4388  Click image for larger version

Name:	HST_US3498.JPG
Views:	101
Size:	82.8 KB
ID:	4389  
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  #2  
Old December 24th 12, 10:51 PM posted to alt.binaries.pictures.astro
Stefan Lilge
external usenet poster
 
Posts: 2,269
Default ASTRO: IC 277

Rick,

that's an interesting object. Must be really faint.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
...

IC 277 is a galaxy with a large plume suggested to me by Sakib Rasool.
It is about 120 million light-years distant in the constellation of
Cetus. Why it has such a huge plume is the issue. It might be due to a
nearby galaxy. The one to the north is often cited as being related.
Problem is there's no redshift info on it and it doesn't appear
distorted. Usually such a small galaxy would be torn apart by the far
larger one not the other way around. That's the problem with the others
nearby as well. Either the culprit has moved on or this is the result
of a merger. I find nothing in the literature to help.

While the Sloan survey has images of this area, none of the data is in
NED. That left only two other objects in the field for which NED had
distance data. I wasn't going to prepare an annotated image but then
looked at these two. They are both listed as quasars. One of which is
so different from what I normally think of as being a quasar I decided
it was worth covering. This is [HB89] 0257+024/US3498. NED lists it as
being a galaxy, a quasar, a blue star and a UvES object. Wow, what an
overachiever this guy is. The distance listed is only 1.45 billion
light-years. Super close for a quasar. In my image it looks like a
quite normal spherical reddish galaxy. It looks the same on the Sloan
image. Yet this is what a note at NED has to say about it:
"The host of this radio-quiet quasar is dominated by a disc component
with a best-fitting scalelength of r_1/2_ = 10 kpc (Fig. 1n). The
model-subtracted image in Fig. A14 shows a ring of emission at ~4 arcsec
radius. Also revealed is substantial residual flux in the inner ~2
arcsec where the host galaxy is bulge-dominated. This feature can also
be clearly seen in the luminosity profile shown in Fig. 1(n). As a
result of the central bulge, the variable-beta model chooses a
substantially lower value of beta (0.75), and offers a significantly
better {chi}^2^ fit than a pure exponential disc. Nevertheless, this
transpires to be the most disc-dominated host galaxy in the quasar
sample observed to date."

The full paper can be seen at:
http://adsabs.harvard.edu/cgi-bin/bi...NRAS.308..377M though
I've reproduced about all it has on this particular one. Since it was
done with HST data I did look that up and have included a quick and
dirty process of the mono HST image of this galaxy. Shows what appears
to be a Sa tightly wound spiral with a very bright core compared to the
disk. Arms are of very low contrast to the image is done in the red
region of the spectrum 675nm so would likely suppress the disk region
and lower arm contrast. Note the really strange galaxy to the northwest
in the HST image. Seems strangeness is rather common if you look deep
enough.

The other quasar is at a more common distance for a quasar. No galaxy
is seen, just a very blue star-like object. NED lists 4 objects as UvES
from the US catalog (USher Faint Blue Stars). Often these turn out to
be quasars. Until the Sloan data is published there's no way to tell if
they are just blue stars or quasars. I've labeled them on the annotated
image. As usual, if no distance data is available I use a question mark
where it would normally appear.

I saw a blue frame was lost to clouds and replaced it but missed that a
green one was also lost to clouds so had to process it with one less
green frame than normal. Also I thought two luminance frames were
unusable due to clouds so retook two. Turned out it was slightly better
using all 6.

14 LX200R @ f/10, L=6x10 RB=2x10 G=1x10, STL-11000XM, Paramount ME

Rick
--
Prefix is correct. Domain is arvig dot net

 




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