Author Topic: Wednesday, 16th March, 2011: a controversial galaxy  (Read 25254 times)

JeanTate

  • OotD posters
  • Hero Member
  • *****
  • Posts: 2976
    • View Profile
Wednesday, 16th March, 2011: a controversial galaxy
« on: March 16, 2011, 07:01:03 am »


Of course, a galaxy is just a galaxy; any controversy is a human invention.

This galaxy is NGC 7603 (in our very own NGC Catalogue thread), a.k.a. SDSS J231856.65+001437.9, UGC 12493 (not yet in our UGC Catalog thread!), Arp 92 (in our very own The  ARP Peculiar Galaxy Atlas thread), Mrk (Markarian) 530 (not yet in our Another great Markarian, we need a thread for these. thread), 2MASX J23185663+0014376 (not yet in our 2MASX Catalog thread), MCG +00-59-021 (not yet in our MCG Catalog thread), ...

As you'd expect, such a nice looking galaxy has been posted in this forum many, many times!  :)

Curiously, the earliest posting that I could find was by LizPeter, on September 29, 2008, in the Place your lenticular (S0) galaxies in this thread thread - does anyone know of an earlier post?

Randy C wrote a long post on this galaxy - and the controversy (such as it is) - in the Biggest cosmic trainwrecks - Mergers thread (quoted by Mukund Vedapudi here), and a shorter note in the Oddballs- Post your weird pics here! thread; LankyYankee commented too, in the Near misses or hit and runs. (Galaxies that never merged) thread:
Quote
NGC 7589  587731186736234518 (right) and NGC 7603  587731186736300067 (left) both z=0.030 are each much more disturbed than they would be if they were merely interacting at the distance that now exists between them, so it appears that they recently had a close encounter.  The small galaxy at far left, NGC 7603B 587731186736300068 is a neighbor by projection, z=0.056

joinpep mentions this galaxy, among others, in a post titled Enigma Variations: Z-scapes to Ponder (in the What's a QSO? thread):
Quote
587731186736300076 z .394 and another object z .245 are 'possessions' of NGC 7603 z .029. This menagerie is amazing even though there are many other galaxies possessing numerous EV yet to be characterized. It is amazing because the objects are splayed in a dynamic 2-D array and ripe for observation without extraneous clutter. One can't help but machinate an environment that can produce such a spatial result. Btw, that pendular object hanging at the left terminus is z .057.

So what's the controversy?

In a nutshell, it's the fantastic ability of the human brain to spot patterns vs its notorious inability to grasp the finer points of statistics, intuitively.

See that nice round galaxy seemingly at the end of NGC 7603's arm (NGC 7603B is its name)? It's got a quite different redshift from that of NGC 7306 itself; 0.057 vs 0.029, as several zooites have noted. It sure looks like there's a close encounter of the galaxy kind going on here, doesn't it?

It gets more thrilling.

In NGC 7603's arm, the one 'connecting' it to NGC 7603B, are two small blobs ('blobs' because they are, or seem to be, extended sources, not point-like, or star-like, ones); they have highly 'discordant' redshifts, as both RandyC and joinpep noted.

Seeing this pattern (and several somewhat like it), many a person's brain thinks 'what are the chances that THAT is just a co-incidence?!?' And perhaps those of us who've done some statistics will have a go at working out an answer.

One of the most widely cited papers on this 'system' - cited by people other than other astronomers! (who've cited it but rarely) - is one by M. López-Corredoira and C.M. Gutiérrez, "Two emission line objects with z>0.2 in the optical filament apparently connecting the Seyfert galaxy NGC 7603 to its companion"; here's the abstract:
Quote
We present new spectroscopic observations of an old case of anomalous redshift--NGC 7603 and its companion. The redshifts of the two galaxies which are apparently connected by a luminous filament are z=0.029 and z=0.057 respectively. We show that in the luminous filament there are two compact emission line objects with z=0.243 and z=0.391. They lie exactly on the line traced by the filament connecting the galaxies. As far as we are aware, this is the most impressive case of a system of anomalous redshifts discovered so far.

It's pretty easy to understand why the human brain has a tendency to see patterns where there are, in fact, none; a slight in-built bias towards false positives - as such are called - must surely be an advantage, from an evolutionary perspective (a slight in-built bias towards false negatives would, on average, result in you being eaten rather than living to have offspring another day!). On top of that, galaxies are not the kinds of patterns we have hard-wired into our brains, unlike faces for example.

So, to assess the reality of patterns like those we see in NGC 7603 - as in 'are they really, in 3D space, truly all connected?' reality - we need to do some calculations, of the statistical kind. Unfortunately, even things that affect us in our daily lives are hard for many of us to grasp, statistically speaking (that's why 'lies, damned lies, and statistics' rings so true, right?), so it's surely no surprise to learn that the statistics of quasar-galaxy associations (or galaxy-galaxy associations) can sometimes trip up even the best astronomers.

If you're interested in digging deeper, I recommend a webpage entitled "Alternate Approaches and the Redshift Controversy", by our very own NGC 3314, as a good place to start.

Thomas J

  • Hero Member
  • *****
  • Posts: 6939
  • Do the best you can, while you can
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #1 on: March 16, 2011, 09:44:08 am »
Thanks for a very interesting OOTD, Jean. it's true how the brain can make assumptions like this. It really does look as though the smaller galaxy is drawing in the spiral arm, but as you say, it's much more distant and only a projection.

Here's a zoomed out image showing the other galaxy at z =0.029

« Last Edit: March 16, 2011, 02:31:17 pm by Thomas J »
I am very interested in the Universe- I am specialising in the Universe and all that surrounds it.....            Peter Cook.


Bruno

  • OotD posters
  • Hero Member
  • *****
  • Posts: 4985
  • Alta in caelo splendet luna micant stellae mille et una
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #2 on: March 16, 2011, 10:13:21 am »
Very often we want to see things where actual numbers say no, but we insist on declaring those numbers anomalous
Thanks JT  8)
Ciao
Bruno

Cadunt lilia, surgunt rosae
Stellae in caelo sunt radiosae

Alice

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 31782
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #3 on: March 16, 2011, 10:40:48 am »
Soooo interesting! What a sneaky little galactic gaggle :o

AlexandredOr

  • Hero Member
  • *****
  • Posts: 25423
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #4 on: March 16, 2011, 11:52:42 am »
Great ! Nice and informative OotD  :D
Thx Jean  :D

Baby star opening its eyes on the Universe.

Lightbulb500

  • OotD posters
  • Hero Member
  • *****
  • Posts: 2354
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #5 on: March 16, 2011, 06:31:24 pm »
A stunning Galaxy, and a wonderful OOTD Jean ;D

RandyC

  • Hero Member
  • *****
  • Posts: 6725
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #6 on: March 17, 2011, 11:54:40 am »
I have explained the phenomenon many times in my Excitation Volume Galaxies thread. Quasar - Galaxy pairs form the filaments which connect galaxies. The filaments are actually volumes which differ from the voids. Think golfing: Fairway versus the Rough. Light travels different in a filament versus the rough..ever so slightly. When we first started with GZ, we thought a potential interaction beween galaxies at z=0.030 and z=0.056 was impossible. Now, after looking at umpteen million mergers, we know its in the realm of interaction. While the galaxy-QSO pairs may not often interact visibly, they form the filaments. Depending on how the orientation of the QSO and filament, and how we see the QSO light affects its redshift. For example, if we see the QSO light emitted from the filament at the foreground galaxy, then that is one reading. If we see the QSO light emitted behind and not through the filament, then that is another reading.

I think its safe to assume that these orientation of galaxy arms and high redshift quasars exist. The beauty of GZ is that we have threads to separate illusions from reality. Just take a look at the EV thread. Whether you believe in the theory or not, we have seen enough now to know the phenomenon exists.
Randy

Mukund Vedapudi

  • OotD posters
  • Hero Member
  • *****
  • Posts: 5994
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #7 on: March 17, 2011, 12:54:29 pm »
Cool :) :)
Faith is the bird singing when the dawn is yet dark.

zutopian

  • Hero Member
  • *****
  • Posts: 2852
  • REOPEN this forum!!!
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #8 on: March 17, 2011, 12:55:02 pm »
Nice one! Well presented!
I have the impression, as if NGC 7603 plays soccer with that round galaxy!
It reminds me of the following one.

I proudly ;D present the Hubble image together with the SDSS image of CGCG 036-024:



Survey: COSMOS                                                                   
Survey reference: 20105981                                                               587727944034287634
http://www.galaxyzoo.org/examine/AHZ2000v9o

« Last Edit: March 17, 2011, 08:44:25 pm by zutopian »

Alice

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 31782
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #9 on: March 17, 2011, 02:32:02 pm »
Re Randy's post. If there is the slightest evidence among our scientific findings that galaxies with such different redshifts can be interacting, much less quasars at much further redshifts whose light simply happens to be passing through other galaxies, I'd love to see it - in a scientific paper, with some kind of proof, not just speculation. The whole point of this Object of the Day is that these galaxies look as if they are interacting, but are not.

Similarly, of course light is affected by the material it passes through - this does not mean the light source is affected.

I'm not saying speculation is wrong - speculation is great - but it mustn't be confused with conclusive proof.
« Last Edit: March 17, 2011, 03:40:22 pm by Alice »

NGC3314

  • Global Moderator
  • Hero Member
  • ****
  • Posts: 1590
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #10 on: March 17, 2011, 04:28:14 pm »
Whether you believe in the theory or not, we have seen enough now to know the phenomenon exists.

It is quite true in the general sense - establishing a phenomenon is quite distinct from having a theory to explain it.

Can you put together a concise summary of your strongest evidence - tabular, image collection, whatever is best - to identify the phenomenon precisely?

zutopian

  • Hero Member
  • *****
  • Posts: 2852
  • REOPEN this forum!!!
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #11 on: March 18, 2011, 09:32:12 pm »
Re Randy's post. If there is the slightest evidence among our scientific findings that galaxies with such different redshifts can be interacting, much less quasars at much further redshifts whose light simply happens to be passing through other galaxies, I'd love to see it - in a scientific paper, with some kind of proof, not just speculation. The whole point of this Object of the Day is that these galaxies look as if they are interacting, but are not.

Similarly, of course light is affected by the material it passes through - this does not mean the light source is affected.

I'm not saying speculation is wrong - speculation is great - but it mustn't be confused with conclusive proof.
I found a paper:
 "1107+036 - an unusual QSO-galaxy pair"
Murdoch, H. S.; Hunstead, R. W.; Arp, H. C.; Blades, J. C.; Burbidge, E. M.; Condon, J. J.
Astrophysical Journal, Part 1, vol. 265, Feb. 15, 1983, p. 610-619. Research supported by the Australian Research Grants Committee
http://adsabs.harvard.edu/abs/1983ApJ...265..610M

I wonder, if there is any news, since the paper is from 1983!

zutopian

  • Hero Member
  • *****
  • Posts: 2852
  • REOPEN this forum!!!
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #12 on: March 18, 2011, 11:08:29 pm »
Re Randy's post. If there is the slightest evidence among our scientific findings that galaxies with such different redshifts can be interacting, much less quasars at much further redshifts whose light simply happens to be passing through other galaxies, I'd love to see it - in a scientific paper, with some kind of proof, not just speculation. The whole point of this Object of the Day is that these galaxies look as if they are interacting, but are not.

Similarly, of course light is affected by the material it passes through - this does not mean the light source is affected.

I'm not saying speculation is wrong - speculation is great - but it mustn't be confused with conclusive proof.
I found a paper:
 "1107+036 - an unusual QSO-galaxy pair"
Murdoch, H. S.; Hunstead, R. W.; Arp, H. C.; Blades, J. C.; Burbidge, E. M.; Condon, J. J.
Astrophysical Journal, Part 1, vol. 265, Feb. 15, 1983, p. 610-619. Research supported by the Australian Research Grants Committee
http://adsabs.harvard.edu/abs/1983ApJ...265..610M

I wonder, if there is any news, since the paper is from 1983!
I found the "unusual QSO-galaxy pair" in SDSS: Both have spectra charts!

DR7: http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587726033853743225
DR8: http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237651755078647951

Please do an OOTD about them!

RandyC

  • Hero Member
  • *****
  • Posts: 6725
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #13 on: March 19, 2011, 06:43:58 pm »
Whether you believe in the theory or not, we have seen enough now to know the phenomenon exists.

It is quite true in the general sense - establishing a phenomenon is quite distinct from having a theory to explain it.

Can you put together a concise summary of your strongest evidence - tabular, image collection, whatever is best - to identify the phenomenon precisely?

Okay, i will see what I can put together as I had written a short piece already. Basically, I am saying quasars are excitation volumes which may affect redshifts of emitted light. Also, I now believe the filaments are similar volumes that may transport light like fiber optics.
« Last Edit: March 19, 2011, 06:45:53 pm by RandyC »
Randy

zutopian

  • Hero Member
  • *****
  • Posts: 2852
  • REOPEN this forum!!!
    • View Profile
Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #14 on: March 20, 2011, 09:08:38 pm »
Re Randy's post. If there is the slightest evidence among our scientific findings that galaxies with such different redshifts can be interacting, much less quasars at much further redshifts whose light simply happens to be passing through other galaxies, I'd love to see it - in a scientific paper, with some kind of proof, not just speculation. The whole point of this Object of the Day is that these galaxies look as if they are interacting, but are not.

Similarly, of course light is affected by the material it passes through - this does not mean the light source is affected.

I'm not saying speculation is wrong - speculation is great - but it mustn't be confused with conclusive proof.
I found a paper:
 "1107+036 - an unusual QSO-galaxy pair"
Murdoch, H. S.; Hunstead, R. W.; Arp, H. C.; Blades, J. C.; Burbidge, E. M.; Condon, J. J.
Astrophysical Journal, Part 1, vol. 265, Feb. 15, 1983, p. 610-619. Research supported by the Australian Research Grants Committee
http://adsabs.harvard.edu/abs/1983ApJ...265..610M

I wonder, if there is any news, since the paper is from 1983!
I found the "unusual QSO-galaxy pair" in SDSS: Both have spectra charts!

DR7: http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587726033853743225
DR8: http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237651755078647951

Please do an OOTD about them!

Here are further papers:

"Associations between quasi-stellar objects and galaxies"
Burbidge, G.; Hewitt, A.; Narlikar, J. V.; Gupta, P. Das
Publication Date: 11/1990
http://adsabs.harvard.edu/cgi-bin/bib_query?1990ApJS...74..675B

"The reality of anomalous redshifts in the spectra of some QSOs and its implications. "
Burbidge, G.
Publication Date: 05/1996
http://adsabs.harvard.edu/cgi-bin/bib_query?1996A%26A...309....9B