ASTRO: IC 1087 A very close pair of galaxies

IC 0187 is a pair of galaxies in Triangulum on the border with Aries.
In fact UGC 01533 (upper left corner) is in Aries. IC 0187 is a SBa
spiral about 220 million light-years from us. UZC J020133.7+262902 is
superimposed on IC 0187. The ALFALFA catalog considers them a merging
system though the UGC calls them simply superimposed galaxies. Are they
merging? The smaller UZC galaxy does seem to have a faint plume on the
northeastern ansa. This may just be normal for the galaxy. I see no
sign of interaction distorting the form of the larger IC 0187. With no
redshift data for the UZC galaxy I have to consider this as yet an
unanswered question. The ALFALFA data is taken with the Arecibo radio
telescope. Radio data may show features unseen at visual wavelengths.
I didn't see any explanation as to why they consider this a merging
system. Both galaxies are rather red in color with few new stars.
Interaction often triggers star formation. Both appear to have plenty
of dust and likely gas for this. I lean toward no interaction but it
wouldn't take much to change my mind. Obtaining a redshift for UZC
J020133.7+262902 might help settle this question.

The field is rather poorly covered at NED. I've identified every galaxy
in the field noted at NED, most have no magnitude, redshift or
classification data. The only exceptions besides IC 0187 is IC 0188 and
UGC 01533. IC 0188 has almost exactly the same redshift as IC 0187 so
is likely a true companion. NED classifies it as S?. It's core is
sloshed in that it is well off center. This is usually considered a
sure sign of interaction. Could the possible tidal features of the UZC
galaxy be due to interaction with IC 0188 rather than IC 0187? I'd
think if IC 0187 had "sloshed IC 0188 it would show some sign of it as
the mass difference doesn't seem sufficient to protect it. IC 0188 is
much bluer than IC 0187. This color is consistent with it interacting
with something and its "sloshed" state.

UGC 01533 is a rather typical barred spiral classed as SABcd:. It is
nearly 3 times more distant than IC 0187 and IC 0188.

The vast majority of the galaxies in the image are unlisted at NED
though Sloan has imaged this field. I expect it eventually to be
included at NED but until then this will have to do.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

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

That should be IC 0187.

Rick

On 4/15/2014 11:23 PM, Rick Johnson wrote:
IC 0187 is a pair of galaxies in Triangulum on the border with Aries. In
fact UGC 01533 (upper left corner) is in Aries. IC 0187 is a SBa
spiral about 220 million light-years from us. UZC J020133.7+262902 is
superimposed on IC 0187. The ALFALFA catalog considers them a merging
system though the UGC calls them simply superimposed galaxies. Are they
merging? The smaller UZC galaxy does seem to have a faint plume on the
northeastern ansa. This may just be normal for the galaxy. I see no
sign of interaction distorting the form of the larger IC 0187. With no
redshift data for the UZC galaxy I have to consider this as yet an
unanswered question. The ALFALFA data is taken with the Arecibo radio
telescope. Radio data may show features unseen at visual wavelengths. I
didn't see any explanation as to why they consider this a merging
system. Both galaxies are rather red in color with few new stars.
Interaction often triggers star formation. Both appear to have plenty
of dust and likely gas for this. I lean toward no interaction but it
wouldn't take much to change my mind. Obtaining a redshift for UZC
J020133.7+262902 might help settle this question.

The field is rather poorly covered at NED. I've identified every galaxy
in the field noted at NED, most have no magnitude, redshift or
classification data. The only exceptions besides IC 0187 is IC 0188 and
UGC 01533. IC 0188 has almost exactly the same redshift as IC 0187 so
is likely a true companion. NED classifies it as S?. It's core is
sloshed in that it is well off center. This is usually considered a
sure sign of interaction. Could the possible tidal features of the UZC
galaxy be due to interaction with IC 0188 rather than IC 0187? I'd
think if IC 0187 had "sloshed IC 0188 it would show some sign of it as
the mass difference doesn't seem sufficient to protect it. IC 0188 is
much bluer than IC 0187. This color is consistent with it interacting
with something and its "sloshed" state.

UGC 01533 is a rather typical barred spiral classed as SABcd:. It is
nearly 3 times more distant than IC 0187 and IC 0188.

The vast majority of the galaxies in the image are unlisted at NED
though Sloan has imaged this field. I expect it eventually to be
included at NED but until then this will have to do.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick


--
Prefix is correct. Domain is arvig dot net

Rick,

that's probably the closest you can get before the final merger (assuming
they are at the same distance).
Although your notes show no evidence of interaction I am missing the
southern end of the edge-on part.
But indeed both galaxies look pretty much unchanged, which would be unusual
if they were as close as they look to be.

Anyway, you image shows a lot of detail, otherwise we would have nothing to
speculate about...

Stefan


"Rick Johnson" schrieb im Newsbeitrag
...

IC 0187 is a pair of galaxies in Triangulum on the border with Aries.
In fact UGC 01533 (upper left corner) is in Aries. IC 0187 is a SBa
spiral about 220 million light-years from us. UZC J020133.7+262902 is
superimposed on IC 0187. The ALFALFA catalog considers them a merging
system though the UGC calls them simply superimposed galaxies. Are they
merging? The smaller UZC galaxy does seem to have a faint plume on the
northeastern ansa. This may just be normal for the galaxy. I see no
sign of interaction distorting the form of the larger IC 0187. With no
redshift data for the UZC galaxy I have to consider this as yet an
unanswered question. The ALFALFA data is taken with the Arecibo radio
telescope. Radio data may show features unseen at visual wavelengths.
I didn't see any explanation as to why they consider this a merging
system. Both galaxies are rather red in color with few new stars.
Interaction often triggers star formation. Both appear to have plenty
of dust and likely gas for this. I lean toward no interaction but it
wouldn't take much to change my mind. Obtaining a redshift for UZC
J020133.7+262902 might help settle this question.

The field is rather poorly covered at NED. I've identified every galaxy
in the field noted at NED, most have no magnitude, redshift or
classification data. The only exceptions besides IC 0187 is IC 0188 and
UGC 01533. IC 0188 has almost exactly the same redshift as IC 0187 so
is likely a true companion. NED classifies it as S?. It's core is
sloshed in that it is well off center. This is usually considered a
sure sign of interaction. Could the possible tidal features of the UZC
galaxy be due to interaction with IC 0188 rather than IC 0187? I'd
think if IC 0187 had "sloshed IC 0188 it would show some sign of it as
the mass difference doesn't seem sufficient to protect it. IC 0188 is
much bluer than IC 0187. This color is consistent with it interacting
with something and its "sloshed" state.

UGC 01533 is a rather typical barred spiral classed as SABcd:. It is
nearly 3 times more distant than IC 0187 and IC 0188.

The vast majority of the galaxies in the image are unlisted at NED
though Sloan has imaged this field. I expect it eventually to be
included at NED but until then this will have to do.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

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