Object of the Week January 19, 2014 Discordant Redshifts A few Examples from Dr Arp

[Jimi Lowrey]

I have had Dr Halton "Chip" Arp on my mind a lot the last few weeks since his passing. It seems to me after the many many hours reading his papers over the years that I have lost a old friend. I thought for this OOTW I would show a few examples of his many discordant redshift galaxies. I know most of you know of the poster child of discordant redshift NGC 4319 and Mrk 205 here are a few others.

NGC 7603 AKA Arp 92

Pisces

RA
23 18 56
DEC
+00 14 38

Redshift

NGC 7603 Z .029524

NGC 7603B Z .055742

1066

It sure looks like the galaxies are interacting? What do you think?

This object is from the 1971 paper if you would like to read more http://adsabs.harvard.edu/abs/1971ApL.....7..221A

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NGC 1199 AKA Hickson 22A and 2Masxi j0303366-153740

Eridanus

RA
03 03 38
DEC
-15 36 50

Redshift

NGC 1199 Z.008573

2MASXi j0303366-153740 Z.044400

10631064

Arp thought that the 2 Masxi galaxy was foreground of NGC 1199? I am not so sure? What do you think?

This is from the 1978 paper http://adsabs.harvard.edu/abs/1978ApJ...220..401A

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NGC 1232 AKA Arp 41 and NGC 1232A

Eridanus

RA
03 39 45
Dec
-20 34 52

Redshift

NGC 1232 Z.005347

NGC 1232A Z.022012

1065

NGC 1232 sure looks like it is merging with NGC 1232A to me this one is a real head scratcher. What do you think??

This Object is from the 1982 paper.http://adsabs.harvard.edu/abs/1982ApJ...263...54A

These are just a few of Arps examples of galaxies with discordant redshifts, I have enjoyed viewing many of them over the years and will continue to read and seek out others to observe. Halton "Chip" Arp might be gone but I am sure he will not soon be forgotten. I know that I will think of him every time I observe one of his "Peculiar Galaxies"! Thanks for the Memories!

"GIVE IT A GO AND LET US KNOW"

GOOD LUCK AND GREAT VIEWING!

[Uwe Glahn]

Good choice to dedicate the OOTW to Arp's objects Jimi. And the objects are also well chosen, I love to look at those discordant redshift galaxies.

The two 2MASXi galaxies were to tough for my old 16", I found no entry in my observing list.

But NGC 1232 is really a very good example to scratch heads. It really looks like an original merger. The color and these structures deceive us. I had the chance to observe and sketch both "distant" related objects from the top of the ORM (http://www.iac.es/eno.php?op1=2&lang=en) at La Palma with my 14,5".

http://www.deepsky-visuell.de/Zeichnungen/NGC1232.jpg

My discordant redshift galaxy favorite is HCG 55 - VV 172 (http://adsabs.harvard.edu/full/1968ApJ...153L.135S). Other cool pair I remember is NGC 4496A,B - VV 76 (http://articles.adsabs.harvard.edu/full/1988PASP..100.1233F)

[Howard B]

Hi Jimi, I really enjoy these discordant redshift pairs too, but of the three objects above I only have one observation of NGC 7603 from December 2009. It really isn't much but here are my notes and sketch:

"This was considerably fainter than I expected but star hopping got me to the same galaxy twice and the photo in the Arp book confirms I got the right faint galaxy - and companion! At mag 16.8 that's pretty good in these less than perfect viewing conditions. 7603 needs a darker, steadier sky but both objects are there, with "B" needing only casual averted vision to pop out. 253x and 408x, SQM 21.07."

1073 1074