ASTRO: NGC 6240 A classic train wreck

How Arp missed or decided against putting this rather famous galaxy in
his catalog I can't fathom. During the time of his atlas the best
anyone could do in understanding this one was shown in comments like
this from a 1964 paper: "Complex core with strong dark lane. Distorted.
Faint outer filament. No nearby object of similar size. Another very
peculiar object." We now know this is the result of a galaxy merger.
It has two nuclei only 1.8" apart. As the early paper says it is quite
alone in space. This makes the merger all the more surprising. The
galaxy is a super luminous IRAS (infrared) galaxy and a starburst
galaxy. Both likely the result of the merger. It has spectral
characteristics of LINER and Seyfert 2 galaxies. Redshift puts it 335
million light-years away and is seen against the stars of Ophiuchus. It
is well covered by the HST. They say it is 400 million light years
distant. I can't explain the difference but it does show the difficulty
of determining distance to such objects. For further information on
this merger and to see the great HST image of it go to:
http://www.spacetelescope.org/static...heic0810ai.jpg

The only other galaxy in the image with any redshift data is HELLAS 190.
This is an X-ray catalog with very poor resolution. The error bar was
so large several possible objects were within the error circle, all very
near the limit of my image. Its redshift puts it 4.2 billion light
years away. Virtually everything else comes from the 2MASS survey of
infrared objects. None have any distance data.

14" LX200R @ f/10, L=5x10' RGB=2x10'x3, 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".

Rick,

very good image.
There are a number of similar objects, the one I can remember by name is NGC
520.

Stefan

"Rick Johnson" schrieb im Newsbeitrag
.com...
How Arp missed or decided against putting this rather famous galaxy in
his catalog I can't fathom. During the time of his atlas the best
anyone could do in understanding this one was shown in comments like
this from a 1964 paper: "Complex core with strong dark lane. Distorted.
Faint outer filament. No nearby object of similar size. Another very
peculiar object." We now know this is the result of a galaxy merger.
It has two nuclei only 1.8" apart. As the early paper says it is quite
alone in space. This makes the merger all the more surprising. The
galaxy is a super luminous IRAS (infrared) galaxy and a starburst
galaxy. Both likely the result of the merger. It has spectral
characteristics of LINER and Seyfert 2 galaxies. Redshift puts it 335
million light-years away and is seen against the stars of Ophiuchus. It
is well covered by the HST. They say it is 400 million light years
distant. I can't explain the difference but it does show the difficulty
of determining distance to such objects. For further information on
this merger and to see the great HST image of it go to:
http://www.spacetelescope.org/static...heic0810ai.jpg

The only other galaxy in the image with any redshift data is HELLAS 190.
This is an X-ray catalog with very poor resolution. The error bar was
so large several possible objects were within the error circle, all very
near the limit of my image. Its redshift puts it 4.2 billion light
years away. Virtually everything else comes from the 2MASS survey of
infrared objects. None have any distance data.

14" LX200R @ f/10, L=5x10' RGB=2x10'x3, 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".