Arp 53 Lots of questions -- no answers

Arp 53/NGC 3290 is located in Hydra about 490 million light-years
distant according to its red shift. Arp put it in his category for
spirals with high surface brightness companions on an arm. He made no
comment on it. NED classes it as SAB(rs)bs pec with HII emission. The
obvious feature of this one is the long arm with a blue knot (the "high
surface brightness companion"). But what's really strange is that the
arm is shadowed by a fainter more diffuse but disconnected arm that runs
parallel to the major arm. The "companion" isn't listed as a separate
galaxy at NED but then most of the galaxies in the image aren't
cataloged. In fact NED lists no galaxies within 9.9 minutes of arc of
Arp 53! The only galaxy in the image with a red shift measurement
besides Arp 53 is the IR source 2MASX J10360744-1721350. It is the
vertical oval galaxy southeast of Arp 53 and east of the bright M
(orange) star in the image toward the lower left corner. It is 480
million light-years away so likely related to Arp 53. Though it shows
no distortion so likely has never interacted with it.

So what caused the drawn out arm with its shadow companion? Likely some
interaction which could be due to that blue object on the arm. None of
the papers I found seem to see it as a separate galaxy, just referring
to the arm has having bright knots. Unfortunately, it is out of the
Sloan survey field so they've not weighed in on this issue. A search
turned up no likely candidate even well out of my field of view. It
could be the blue blob is to blame but I'm not sold on this. I wonder
if this one isn't the result of a merger. I see that as more likely to
create an apparent shadow arm. There are plenty of examples of M51 type
systems with a companion on the arm. None have shadow arms but some
mergers do create arcs of stars that haven't yet returned to the
galaxy's halo. It could be this is one that by line of sight happens to
about follow the arm. Yeah that's a huge reach too. Probably too much
of one. So this one will have to await further imaging of it. HST are
you listening?

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp53.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,

not bad for a galaxy at -17 degrees!!!
I agree that I can't see a companion here...

Stefan

"Rick Johnson" schrieb im Newsbeitrag
ster.com...
Arp 53/NGC 3290 is located in Hydra about 490 million light-years
distant according to its red shift. Arp put it in his category for
spirals with high surface brightness companions on an arm. He made no
comment on it. NED classes it as SAB(rs)bs pec with HII emission. The
obvious feature of this one is the long arm with a blue knot (the "high
surface brightness companion"). But what's really strange is that the
arm is shadowed by a fainter more diffuse but disconnected arm that runs
parallel to the major arm. The "companion" isn't listed as a separate
galaxy at NED but then most of the galaxies in the image aren't
cataloged. In fact NED lists no galaxies within 9.9 minutes of arc of
Arp 53! The only galaxy in the image with a red shift measurement
besides Arp 53 is the IR source 2MASX J10360744-1721350. It is the
vertical oval galaxy southeast of Arp 53 and east of the bright M
(orange) star in the image toward the lower left corner. It is 480
million light-years away so likely related to Arp 53. Though it shows
no distortion so likely has never interacted with it.

So what caused the drawn out arm with its shadow companion? Likely some
interaction which could be due to that blue object on the arm. None of
the papers I found seem to see it as a separate galaxy, just referring
to the arm has having bright knots. Unfortunately, it is out of the
Sloan survey field so they've not weighed in on this issue. A search
turned up no likely candidate even well out of my field of view. It
could be the blue blob is to blame but I'm not sold on this. I wonder
if this one isn't the result of a merger. I see that as more likely to
create an apparent shadow arm. There are plenty of examples of M51 type
systems with a companion on the arm. None have shadow arms but some
mergers do create arcs of stars that haven't yet returned to the
galaxy's halo. It could be this is one that by line of sight happens to
about follow the arm. Yeah that's a huge reach too. Probably too much
of one. So this one will have to await further imaging of it. HST are
you listening?

Arp's image:
http://nedwww.ipac.caltech.edu/level...big_arp53.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".