Index to the Arp Thread

[antoniseb]

In this thread, we provide a handy index to the very lengthy Arp discussion.
Turbo-1 has offered to make a preliminary index with links pointing to the section discussing bridges.

[turbo-1]

I will be building this index bit by bit. Edit: I did it all at one sitting - it has been raining all day and my legs are aching from hand-planting the first installment of our garden yesterday. I had initially intended to hot-link all the posts cited, but viewing a single post at a time takes it out of context. I tried looking at a couple of the posts in this manner, but didn't like the result, because seeing the context in which a post was made is often critical to the understanding of the content of the post. For this reason, I will give the post numbers and a brief blurb about why I consider the post important enough to include in the index. Some of these posts may seem mundane, but in the context of the preceeding and following posts, they are important enough to include, even if they only represent a change in someone's line of argument. Some of the subject matter will only seem relevant to those plucky to start in at post 1119 or so, and go through the posts methodically. There are concepts in these posts that can easily fade from memory over time, and I hope the index can help participants go back and find relevant papers, images, etc. If I have missed YOUR favorite post or if you believe that somehow I have misinterpreted your intent as a poster, please shoot me a PM and I'll try to keep the index updated and fairly presented. Thanks.

turbo-1

"A quick index of papers and major (and minor) concepts of the mainstream and the Arpians during our discussions of bridged apparently-interacting galaxy associations."

1119 and 1120 - these are the two long posts by dgruss23 that kicked off the sub-thread re: bridges as evidence for interaction. Visit these posts first and review the papers. I will let dgruss23's words speak for him.

1126 Cougar advances the mainstream view that bridged objects cannot be physically associated if their redshifts are discordant, no matter what other evidence exists for interaction.

1132 Includes a link to the HI rogues's gallery of interacting systems with HI maps overlain.

1135 Ari included a link to N.A. Sharp's 1986 paper on NGC 7603 as well as a recent Aprian paper.

1139 Arpians do not reject the redshift-distance relationship, but are exploring the possibility that there is an intrinsic contribution to redshift in addition to the Hubble relationship.

1146 TomT's concise summary of the points under consideration.

1163 Nereid's summary of why the bridges topic is important and needs to be discussed.

1166 Links to images of NGC 7603 and the HII galaxies embedded in the tidal tail.

1184 Links to Chandra image of Stephan's quintet and image in optical. Is NGC 7320 foreground?

1187 Link to NGC 1232 image. Companion has 4X redshift of host, yet is equally resolved optically.

1208 Atkins provides links to both Chandra and Spitzer imagery of Stefan's Quintet.

1226 Fram's list of redshifts for interacting galaxies.

1228 Ari points out that if many bridges are coincidental alignments of unrelated objects, there should be far more near-misses than bridges.

1246 dgruss23 summarizes the mainstream and Arpian views of the Hubble relationship.

1250 Preliminary redshift review of selected associations from A-M catalog.

1251 Link to paper on spectral variability of NGC 7603 system, including very deep R-band image.

1270 Fram's post re Tidal Dwarf Galaxies as products of galactic interaction.

1282 Summation of 6 pieces of evidence that indicate that NGC 7603 and its companion and the two embedded HII dwarf galaxies are physically interacting.

1285 Response to Cougar, giving two mainstream methods by which massive bodies can be ejected from a galactic core.

1292 dgruss23's comparison of NGC 7603b distance estimate using SBF mehod vs Faber-Jackson relation.

1295 Cougar's illustration of bridges in NGC 7603.

1301 Duane argues that Arpian evidence of ejection are better fit by mainstream merger scenario.

1303 Clarification of Arpian view of ejection vs merger in reply to 1301.

1304 many good points here - perhaps the best is that tails and bridges are not permanent, and are signs of recent interaction.

1307 Deep AAT image of M100 showing straight tidal stream to companion.

1319 Why no chance alignments of apparent M51 types in which the companion is discordantly blueshifted instead of redshifted?

1320 antoniseb asks if we have a catalog of interacting galaxies to determine if the smaller companion "always" has higher redshift.

1323 Links to Sulentic and Arp papers on Markarian 205.

1325 Cougar post re ejection mechanisms.

1326 My reply to Cougar, including possible evolution of ejected black holes from higher-to-lower redshift objects as material infalls and creates accretion zones.

1331 Cougar post re ~1000 kms/s redshift differental being discordant, with example.

1339 First cut (broad criteria for inclusion) at a redshift differential table for bridged associations in the Arp and A-M catalogs.

1341 Explanation of motivation for redshift differential study, including history of the discovery of the Peculiar Galaxy associations before redshift measurements were made.

1354 Cougar - sample size in redshift differential study is too small - not strong evidence for intrinsic redshifts.

1357 Even if the definition of discordant redshift is reduced to 275 km/s, in 100% of the discordant associations, the companion is redshifted WRT the host.

1369 dgruss23 summarized progress to date, asks if we can get agreement between Arpians and mainstream on the subject of bridges.

1370 Cougar rebuts 1369.

1373 my reply to 1370

1387 Ari posts links to 3 Arp papers regarding redshifts and companion galaxies.

1389 Redshifts extracted for NGC 4321 (M100) and (apparently ejected) NGC 4323. Link to deep image.

1392 Cougar questions ejection scenario in M100/NGC 4323

1394 Links to two more Arp papers on discordant redshifts.

1395 my reply to Cougar's post - regarding possible ejection and the origin of the thin tail to NGC 4323

1399 Cougar's critique of the Lopez-Corredoira & Gutierrez paper on NGC 7603.

1403 Ari's reply to Cougar's 1399 post.

1446 Links to 4 papers discussing mechanisms for galactic ejection of massive objects.

1461 Link to Scranton-Menard paper re:- quasar/galaxy correlation.

1463 Link to a posteriori calculation by mainstream paper.

1464 link to paper showing quasar/galaxy anticorrelation and to Michaels Strauss (SDSS) lecture on quasars.

1468 antoniseb re: inverse square law and quasar bightness

1480 Links to papers re: ULXs as evidence for interaction.

1511 Summary of evidence for interaction in NGC 7603 system, including EW comparisons for the two HII galaxies.

1520 Cougar's response to 1511

1528 dgruss23's response to 1520

1530 differential HcV table for M51-type associations, augmented w/ velocity numbers from HyperLeda

1549 How "tight" is the Hubble relationship?

1554 Link to paper on quasar/ULX near nucleus of NGC 7319

1564-1565 redshift periodicity - brief discussion

1567-1568 Statement of problems arising from M51-type velocity differentials.

1571 Cougar links to Bill Keel publication claiming evolution in quasar metallicity

1575 Ari's first cut at the VV catalog redshift differentials.

1578 Link to Michael Strauss lecture on quasars - no evolution in metallicity out to z~6.5

1587 redshiftt differentials for M51-types in AM catalog only.

1588 list of excluded Arp associations for perusal by morphology.

1591 Ari's list of questionable M51 types from VV

1600 time line of Michael Strauss lecture

1602 papers on quasar metallicity - lack of evolution

1614 Fram's suggestion that bridge discussion with redshift tables and stats be split off to Q&A

1615-1617 exchange regarding the Michael Strauss lecture and papers and the contraints that these observations place on theory.

1621-1623 Sandage vs Freedman estimates of Hubble constant - implications for intrinsic redshift.

1624 refined list of M51 candidates - optically selected, and the HcV differentials and stats.

1628-1637 Discussion of AM2052-221 as M51-type.

1651 quote from Bergvall paper "bridge...clearly seen", yet SDSS shows over 21,000 km/s differential HcV (NGC 4441 system)

1652 link to paper showing NGC 4441 association with overlaid HI map showing interaction.

1655 dgruss23 calculation of mass required to produce companion peculiar motion.in high z diffferential systems.

1668 Link to Arp et al paper - all 32 point X-ray sources within 10' of the centers of nearby galaxies that have been optically identified are high redshift objects - AGN or quasars.

1669 gravitational stripping of globular cluster NGC 5466.

1680-1685 Discussion of "considerable resistance" to the study of discordant systems

1707 Cougar summarizes mainstream view of NGC 7603 system

1713-1717 Effects of intrinsic redshift on perceived peculiar motions, inference of DM in clusters.

1718, 1719 On the chances of finding tidally distorted NOT associated with companions.

1720 - 1738 Fingers of God effect as evidence for intrinsic redshifts, how to calculate Hubble constant in light of the correction needed to normalize cluster shapes.

1740 Cougar disagrees that FOG effect can be evidence for intrinsic redshift, invokes cluster dynamics.

1741-1748 Discussion of redshift distributions in clusters relative to FOG effect.

1749-1759 Discussion of Brynjolfsson's plama redshift hypothesis - tangential, not in-depth.

1761-1763 Narlikar variable-mass hypothesis.

1764-1783 Discussion of age problems in BB - early appearance of high-mass systems w/ supersolar metallicity.

1790 dgruss23 reiterates explanation of nature of HII galaxies and quasars within Arpian view. Evidence for interaction of NGC 7603 system.

1791-1804 Continuation of discussion on evidence for interaction in NGC 7603 system, including link to Bill Keel statement regarding intrinsic redshifts in systems dominated by large spirals.

1807-1812 Evidence for interaction in NGC 7603 system.

1813-1818 Ari brainstorming - scenario by which NGC 7603 system redshifts might be organized by ejection/creation time. Further elaboration of nature of HII galaxies.

1822, 1824,1826 Re ordering of high-redshift objects in NGC 7603 system.

1827-1849 Discussion of evidence of interaction in Stefan's Quintet, including low-redshift NGC 7320.

1851-1854 continuation of Stefan's Quintet topic

1855 dgruss23 recaps mainstream view on bridges w/ Zwicky quote

1861 Ari recaps resolution argument and its applicability to M51 system

1862 dgruss23 offers TFR analysis of Stefan's Quintet members NGC 7319, 7320

1866 dgruss23 explains why low-inclination system like M51 is unsuitable for TFR/cepheid calibration

1871, 1872 - link to 1974 conference report by Arp re HII regions in NGC 7318 and 7320, follow up on HII regions

1873-1876 discussion on stellar resolution issue in M51 and applicability to resolution of Stefan's Quintet

1877 recap of supporting evidence for interaction of Stephan's Quintet

1884 Spaceman Spiff - ratio of recessional velocities in Stefan's Quintet is not necessarily a good indicator of distance

1908, 1909 links to papers on H-alpha and HII regions in Stefan's Quintet

1917 NGC 7603 system as a baseline for "chance alignment" statistical analysis

1922 revisiting the observed relation in loose clusters that the largest/brightest member typically has the lowest redshift, with statistical analysis of M81 group. Links to Arp-Sulentic paper on galaxy groups and to M81 group recessional velocity data.

1923 Cougar's argument that past interaction between M81 and M82 ejected M81 toward us

1924 explanation that the effect (largest member has the lowest redshift) is a statistically significant observable. Link to Bill Keel lecture notes page for confirmation.

1925 TomT - how could M82 have ejected M81 and not caused high-velocity motions in the smaller companions in the group.

1926 dgruss23 - mass calculations from angular diameters and rotational velocities shows M81 to be 23 times more massive than M82, negating argument that M82 gravitationally perturbed M81 toward us with a significant velocity.

1928 Cougar - M81 group is a 13-body problem and too complicated to address

1929 rebuttal of post 1928

1930 dgruss23 - rebuttal of post 1928

1931 Cougar's reply to rebuttal

[TomT]

Originally Posted by turbo-1

I will be building this index bit by bit. I had initially intended to hot-link all the posts cited, but viewing a single post at a time takes it out of context. I tried looking at a couple of the posts in this manner, but didn't like the result, because seeing the context in which a post was made is often critical to the understanding of the content of the post. For this reason, I will give the post numbers and a brief blurb about why I consider the post important enough to include in the index.

Hi turbo-1, Antoniseb,
I admire turbo-1 for taking on all this work, and thanks to Antoniseb for providing the Sticky. But wouldn't it be simpler to just separate out all the posts starting with the 2 by dgruss23 at the beginning of the "Bridge Discussion". I think it would be easier to just transfer these to a separate thread on bridges, and it would sure help keep the flow and context of the discussion. I envision having to keep clicking back and forth to follow a topic.
What do others think? Your consideration of this would be appreciated.
TomT

[dgruss23]

I think from the readers perspective it would be much easier to break out the posts relevant to the bridges discussion. If we have links to selected posts, the reader will have to open multiple windows and the flow of the discussion will be harder to follow.

I notice that after the EU thread was locked, Nereid started an index forum and subsequently a specific thread was started on one of the subtopics in that index. The bridges discussion could be treated in a similar fashion.

I appreciate that antoniseb has worked so hard with us on this. Thanks!

[turbo-1]

I agree that breaking out the bridges thread at 1119 and keeping it alive as a separate entity would be preferable to leaving it in "More from Arp et al". Regardless of what new topic we choose to address, there will still be work relating to bridged associations that deserves to be presented in context, and not be cut off with "We're on a different topic now!". Some very interesting things have popped up in this discussion (especially the redshift differential stats in M51-type systems) and I don't anticipate dropping the question at this point. Ari has contributions to make to this subject, and it is not inconceivable that someone else may want to pitch in and help us try to find out why the statistical anomalies exist, and if they track with galaxy morphology, member size, apparent separations, etc. The answers could be important.

I'm for splitting "bridges" from the main thread - it has value (real or potential?) and should not be buried under months of off-topic posts.

Thanks to antoniseb for giving me a chance to post an index in a sticky thread, to at least provide a quick way to recall where the thread has been and find relevant papers. Now if only the next post in this thread could be numbered 1119... If that happens, I will volunteer to keep the index alive and updated, so the thread can be approached (at least to some extent) as a searchable resource to any newcomer to the topic. I think that it is important to encourage discussion and exploration, and feel that it is important in a topic like this to stick to the observations, and try to avoid categorizing people. The ideas of Arp, Hoyle, Narlikar, the Burbidges, etc are interesting, and many seem to survive (and thrive) in the face of broad surveys like SDSS. That does not mean that every person who is interested in Arpian ideas should be herded into a camp where they are forced to defend every Arpian idea. Some of us are quite uncomfortable with the variable-mass idea, and perhaps are interested in learning more about redshift quantization, but are unwilling to be forced to defend it. Arp et al have teased out some very interesting trends in observations. This does not mean that we who are open to discussing their conclusions should be forced to defend them. Thanks again.

[Cougar]

Originally Posted by turbo-1

I will be building this index bit by bit.

Can this be summarized in one or two sentences?

[Thanatos]

It would be interesting to compile a list of observations that might affirm or refute various ideas. Bridges is a good example. Spectroscopy technology is much improved over the past decade. Perhaps we could persuade a bold soul to spare an hour here or there to test some of the more promising ideas.

[Philip Janes]

I have no plans to enter the "Arp" thread, but on behalf of us newcomers who haven't a clue what you're talking about, I'd like to request a clue.

Through some detective work, I was able to find a thread entitled "More from Arp, et al." Is that what this index relates to?

[dgruss23]

Originally Posted by Philip Janes

I have no plans to enter the "Arp" thread, but on behalf of us newcomers who haven't a clue what you're talking about, I'd like to request a clue.

Through some detective work, I was able to find a thread entitled "More from Arp, et al." Is that what this index relates to?

Yes. The thread had a long history with numerous subtopics of discussion so an index was created in an attempt to catalog the highlights of the thread. Most of the index is on the bridges subtopic in which it was debated whether or not bridges between discordant redshift objects can be considered evidence for interaction.

[Cougar]

Originally Posted by dgruss23

Yes. The thread had a long history with numerous subtopics of discussion so an index was created in an attempt to catalog the highlights of the thread.

However, the index, created by an Arp proponent, only covers about 2/3 of the 2,890 postings.

[dgruss23]

Originally Posted by Cougar

However, the index, created by an Arp proponent, only covers about 2/3 of the 2,890 postings.

I think I indicated that - although I don't believe the index actually covers more than ~ 25% of the thread:

Originally Posted by dgruss23

Most of the index is on the bridges subtopic in which it was debated whether or not bridges between discordant redshift objects can be considered evidence for interaction.

[InterPur]

The index I see listed is great...but how do I get to, say, the index point 1126?

Can anyone tell me this?

Thanks,
InterPur

[01101001]

Originally Posted by InterPur

but how do I get to, say, the index point 1126?

Build a URL like

PHP Code:

http://www.bautforum.com/716295-post1126.html


and go there.

That will show the one article. Click on the thread name there to see the article in context.

[antoniseb]

Just a reminder, this thread is intended as an index to important points in large but closed Arp thread. It is here a convenience to people who want to go back and look through parts of that thread, but don't want to read the whole thing (would take weeks).

This is not a place for general posting about Arp, and posts matching that model will be (and have been) removed.

[sarongsong]

Originally Posted by antoniseb

This is not a place for general posting about Arp, and posts matching that model will be (and have been) removed.

So what is "Arp"?

[slang]

Originally Posted by sarongsong

So what is "Arp"?

Who, not what. Wiki on Halton Arp.

[sarongsong]

Originally Posted by Nereid

...We have an entire thread devoted to the discussion of Arp's ideas - More from Arp et al...

Thanks!