A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Others » Astro Pictures
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Arp 275



 
 
Thread Tools Display Modes
  #1  
Old June 18th 15, 09:19 AM
WA0CKY WA0CKY is offline
Senior Member
 
First recorded activity by SpaceBanter: Feb 2008
Posts: 689
Default Arp 275

Arp 275/NGC 2881 is a pair of colliding galaxies in Hydra nearly a quarter billion light-years from earth. Arp had no category for colliding galaxies. Though he did have one for interacting galaxies. Many dozen of his galaxies were interacting but only 6 made this category, This was the first of the 6. Unlike most entries he had no comment for this entry.

The two galaxies making up Arp 275 are also known as VV 293a and VV 293b with VV 293a being the one on the left (east). It is the only one of the pair to have redshift measurements. It isn't classified at NED other than mention it has HII regions. VV 293b to the west is classified at NED as Sbc? pec. A note at NED from the MCG catalog says; "Bright, interacting. Two galaxies Fd in close contact with very large deformations. A note with the VV catalog says; "On the (red) POSS print the two major bodies are not in contact against the background of a homogeneous disk." I can't tell from any image if they are in contact. To me it appears that the eastern galaxy may be slightly in front of the western one. Since I can't really tell where one galaxy ends and the next begins I measure the long axis of the projected pair at about 74,000 light-years. So these aren't very big galaxies, even including the plumes created by their interaction. The pair was discovered by Lewis Swift on February 9, 1886 using a 16" refractor.

The only other galaxy in the image with any information is IC 2482 in the southeast corner of my image. It is listed as an E+ at NED and much closer than Arp 275 at about 175 million light-years. A note at NED says of it; "The gradient of brightness in halo is smaller then in a normal E." Oddly it is quite a bit brighter and larger in angular size than Arp 275 yet wasn't discovered until March 14, 1899 by Herbert Alonzo Howe using a 20" f/15 Alvan Clark-George Saegmuller refractor at Chamberlin Observatory in Denver. How Swift missed it I don't know. While it is partly off my frame I measured its the length of the side fully on the frame and doubled that to get a size of 156,000 light-years. Twice the size of Arp 275. My sister-in-law lives in a southern suburb of Denver and every time I've been there the seeing has been awful. Seems like a poor place for an observatory from my sample. The observatory is right in Denver only about 3 blocks east of the University of Denver campus of which it is a part, right beside tennis courts and ball diamond (both unlit last I knew). Conditions must have been much better in 1899! It still is open two nights a week to show the public the moon and planets, about all you can see from that location today. Howe managed to find 60 IC objects from there. Not much light pollution in his day.

Nothing else on the frame has any distance information useful for an annotated image so I didn't prepare one.

This entry is likely my final Arp galaxy. What remain are either below my horizon or mostly below the wall of the observatory. That's only 7 I can't reach out of 338. I've been working on these now for about 10 years. Nice to finally be finished with them. Though a couple could benefit from a reshoot under better conditions I don't see that happening any time soon. I still have plenty of strange galaxies to take that Arp didn't include. They will keep me busy for quite some time.


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

Rick
Attached Thumbnails
Click image for larger version

Name:	ARP275L4X10RGB2X10.JPG
Views:	306
Size:	415.2 KB
ID:	5751  Click image for larger version

Name:	ARP275L4X10RGB2X10CROP125.JPG
Views:	101
Size:	134.2 KB
ID:	5752  

Last edited by WA0CKY : June 18th 15 at 07:47 PM.
  #2  
Old June 19th 15, 10:05 AM posted to alt.binaries.pictures.astro
Skywise
external usenet poster
 
Posts: 318
Default Arp 275

WA0CKY wrote in news:WA0CKY.fc87c28
@spacebanter.com:

This entry is likely my final Arp galaxy. What remain are either below
my horizon or mostly below the wall of the observatory. That's only 7 I
can't reach out of 338. I've been working on these now for nearly 10
years.


Congrats on your accomplishment. I look forward to your other
"strange" galaxies.

Brian
--
http://www.earthwaves.org/forum/index.php - Earth Sciences discussion
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Sed quis custodiet ipsos Custodes?
  #3  
Old July 5th 15, 11:55 PM posted to alt.binaries.pictures.astro
Stefan Lilge
external usenet poster
 
Posts: 2,269
Default Arp 275

Rick,

these two look like siamese twins. Unusual to have such similar partners in
a merger.
I guess now that you have those Arp galaxies you can turn to some more
exotic objects ;-)

Stefan


"WA0CKY" schrieb im Newsbeitrag ...


Arp 275/NGC 2881 is a pair of colliding galaxies in Hydra nearly a
quarter billion light-years from earth. Arp had no category for
colliding galaxies. Though he did have one for interacting galaxies.
Many dozen of his galaxies were interacting but only 6 made this
category, This was the first of the 6. Unlike most entries he had no
comment for this entry.

The two galaxies making up Arp 275 are also known as VV 293a and VV 293b
with VV 293a being the one on the left (east). It is the only one of
the pair to have redshift measurements. It isn't classified at NED
other than mention it has HII regions. VV 293b to the west is
classified at NED as Sbc? pec. A note at NED from the MCG catalog says;
"Bright, interacting. Two galaxies Fd in close contact with very large
deformations. A note with the VV catalog says; "On the (red) POSS print
the two major bodies are not in contact against the background of a
homogeneous disk." I can't tell from any image if they are in contact.
To me it appears that the eastern galaxy may be slightly in front of the
western one. Since I can't really tell where one galaxy ends and the
next begins I measure the long axis of the projected pair at about
74,000 light-years. So these aren't very big galaxies, even including
the plumes created by their interaction. The pair was discovered by
Lewis Swift on February 9, 1886 using a 16" refractor.

The only other galaxy in the image with any information is IC 2482 in
the southeast corner of my image. It is listed as an E+ at NED and much
closer than Arp 275 at about 175 million light-years. A note at NED
says of it; "The gradient of brightness in halo is smaller then in a
normal E." Oddly it is quite a bit brighter and larger in angular size
than Arp 275 yet wasn't discovered until March 14, 1899 by Herbert
Alonzo Howe using a 20" f/15 Alvan Clark-George Saegmuller refractor at
Chamberlin Observatory in Denver. How Swift missed it I don't know.
While it is partly off my frame I measured its the length of the side
fully on the frame and doubled that to get a size of 156,000
light-years. Twice the size of Arp 275. My sister-in-law lives in a
southern suburb of Denver and every time I've been there the seeing has
been awful. Seems like a poor place for an observatory from my sample.
The observatory is right in Denver only about 3 blocks east of the
University of Denver campus of which it is a part, right beside tennis
courts and ball diamond (both unlit last I knew). Conditions must have
been much better in 1899! It still is open two nights a week to show
the public the moon and planets, about all you can see from that
location today. Howe managed to find 60 IC objects from there. Not
much light pollution in his day.

Nothing else on the frame has any distance information useful for an
annotated image so I didn't prepare one.

This entry is likely my final Arp galaxy. What remain are either below
my horizon or mostly below the wall of the observatory. That's only 7 I
can't reach out of 338. I've been working on these now for nearly 10
years. Nice to finally be finished with them. Though a couple could
benefit from a reshoot under better conditions I don't see that
happening any time soon. I still have plenty of strange galaxies to
take that Arp didn't include. They will keep me busy for quite some
time.


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

Rick


--
WA0CKY

  #4  
Old July 6th 15, 04:47 AM
WA0CKY WA0CKY is offline
Senior Member
 
First recorded activity by SpaceBanter: Feb 2008
Posts: 689
Default

I've added some Voorwerpjes to my to-do list. I've posted the one likely the best of the bunch http://www.spacebanter.com/showthread.php?t=210653 . 2 others have been taken. One is pretty noisy and I'm not sure if I caught the Voorwerpjes around the galaxy or just green noise. The third looks like I got it but my seeing wasn't all that great. I needed a better night. Most of the others are now too far west so will have to wait for next galaxy season.

Rick

[quote=Stefan Lilge;1297255]Rick,

these two look like siamese twins. Unusual to have such similar partners in
a merger.
I guess now that you have those Arp galaxies you can turn to some more
exotic objects ;-)

Stefan
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 02:54 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.