ASTRO: Arp 4

Not surprisingly, Arp 4/MCG -02-05-050 falls under his classification
for low surface brightness spiral galaxies. These tend to be very blue.
That is the case here. It is quite nearby at only about 60 to 65
million light-years away in the constellation of Cetus. It's
classification is IAB(rs)m indicating it is an irregular galaxy with
characteristics of both a barred and normal spiral and falls into the
Magellanic class as does our Magellanic clouds.

It has two companions. To the east is the very obvious spiral MCG
-02-05-050a. It may carry the same catalog number but it certainly
isn't related. Redshift data puts it at about 630 million light-years
or ten times further away. While an obvious spiral I find no
classification at NED. The other companion is star-like and lies on the
other side. To find it go to the obvious star directly west (right)
then up steeply to the star-like companion. Seeing was too poor this
low in the sky (-12 degrees) to see much of its "fuzz". It is
APMUKS(BJ) B014555.12-123703.0. There's no redshift data for it but it
isn't very likely related to Arp 4 though some papers call it a
companion. There are only two other galaxies in the image with redshift
data. One is to the northeast of the bright spiral MCG -02-05-050a. It
is an IR galaxy, 2MASX J01483906-1222128, and appears to be a disk
galaxy. Its redshift shows a distance of about 675 million light-years.
To its east and slightly south is another low surface brightness
galaxy, APMUKS(BJ) B014618.61-123728.4. I find nothing on it however.
The only other galaxy with a known redshift is the bright oval galaxy
near the west edge of the image a bit below Arp 4. It seems oddly red
at one end and blue at the other. Probably an artifact of imaging low
and a change in conditions during the color data collection. In any
case it is listed at about 370 thousand light years. As you likely
guessed NED has no classification for it. It too is a galaxy seen by
IRAS. It is LEDA 174158/IRAS F01451-1239.

The image contains one asteroid, (256308) 2006 WO185 at an estimated
magnitude of 19.0. It is east of Arp 4. There's little else of
interest that I found in this field.

Arp's image:
http://ned.ipac.caltech.edu/level5/A.../big_arp4.jpeg

14" LX200R @ f/10, L=4x10' 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,

that's an amazing target. Too bad it seems to be exceedingly faint, so not
suited for city skies...

Stefan


"Rick Johnson" schrieb im Newsbeitrag
.com...
Not surprisingly, Arp 4/MCG -02-05-050 falls under his classification
for low surface brightness spiral galaxies. These tend to be very blue.
That is the case here. It is quite nearby at only about 60 to 65
million light-years away in the constellation of Cetus. It's
classification is IAB(rs)m indicating it is an irregular galaxy with
characteristics of both a barred and normal spiral and falls into the
Magellanic class as does our Magellanic clouds.

It has two companions. To the east is the very obvious spiral MCG
-02-05-050a. It may carry the same catalog number but it certainly
isn't related. Redshift data puts it at about 630 million light-years
or ten times further away. While an obvious spiral I find no
classification at NED. The other companion is star-like and lies on the
other side. To find it go to the obvious star directly west (right)
then up steeply to the star-like companion. Seeing was too poor this
low in the sky (-12 degrees) to see much of its "fuzz". It is
APMUKS(BJ) B014555.12-123703.0. There's no redshift data for it but it
isn't very likely related to Arp 4 though some papers call it a
companion. There are only two other galaxies in the image with redshift
data. One is to the northeast of the bright spiral MCG -02-05-050a. It
is an IR galaxy, 2MASX J01483906-1222128, and appears to be a disk
galaxy. Its redshift shows a distance of about 675 million light-years.
To its east and slightly south is another low surface brightness
galaxy, APMUKS(BJ) B014618.61-123728.4. I find nothing on it however.
The only other galaxy with a known redshift is the bright oval galaxy
near the west edge of the image a bit below Arp 4. It seems oddly red
at one end and blue at the other. Probably an artifact of imaging low
and a change in conditions during the color data collection. In any
case it is listed at about 370 thousand light years. As you likely
guessed NED has no classification for it. It too is a galaxy seen by
IRAS. It is LEDA 174158/IRAS F01451-1239.

The image contains one asteroid, (256308) 2006 WO185 at an estimated
magnitude of 19.0. It is east of Arp 4. There's little else of
interest that I found in this field.

Arp's image:
http://ned.ipac.caltech.edu/level5/A.../big_arp4.jpeg

14" LX200R @ f/10, L=4x10' 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".