Author Topic: Wednesday, 16th March, 2011: a controversial galaxy  (Read 25284 times)

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #30 on: March 26, 2011, 07:01:01 pm »
(...)

zutopian (and others), you might like to consider just how many quasars were unambiguously reported, in the astronomical literature, in 1983, 1990, and 1996, and how many were discovered by SDSS, the first astronomical results from which - the EDR - were not published until 2002. Given the amazing amount of new data from SDSS - in a form that is extremely uniform - perhaps the relative lack of papers since 2002 on galaxy-quasar associations carries a strong message?

I found a paper, which is from 2005: http://arxiv.org/abs/astro-ph/0501090
"Periodicities of Quasar Redshifts in Large Area Surveys"
Authors: H. Arp, C. Fulton, D. Roscoe
(Submitted on 6 Jan 2005)

Besides I found a paper, which is contrary: http://arxiv.org/abs/astro-ph/0506366
"Critical Examinations of QSO Redshift Periodicities and Associations with Galaxies in Sloan Digital Sky Survey Data"
Authors: Su Min Tang, Shuang Nan Zhang
(Submitted on 16 Jun 2005)

And now I found a "neutral" paper, which is from 2009: "Apparent discordant redshift QSO-galaxy associations"
Interestingly, the author is Martin Lopez-Corredoira: He is also one of the authors of the paper "Two emission line objects with z>0.2 in the optical filament apparently connecting the Seyfert galaxy NGC 7603 to its companion" (Jean Tate cited this paper in the OOTD article.).

"Apparent discordant redshift QSO-galaxy associations" http://arxiv.org/abs/0901.4534
Authors: Martin Lopez-Corredoira
(Submitted on 28 Jan 2009)

PS: Please pay attention to c_cld's interesting post, which he did today! (it isn't related to my post)
« Last Edit: March 26, 2011, 09:51:01 pm by zutopian »

JeanTate

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #31 on: March 29, 2011, 10:36:19 pm »
(...)

zutopian (and others), you might like to consider just how many quasars were unambiguously reported, in the astronomical literature, in 1983, 1990, and 1996, and how many were discovered by SDSS, the first astronomical results from which - the EDR - were not published until 2002. Given the amazing amount of new data from SDSS - in a form that is extremely uniform - perhaps the relative lack of papers since 2002 on galaxy-quasar associations carries a strong message?

I found a paper, which is from 2005: http://arxiv.org/abs/astro-ph/0501090
"Periodicities of Quasar Redshifts in Large Area Surveys"
Authors: H. Arp, C. Fulton, D. Roscoe
(Submitted on 6 Jan 2005)

Besides I found a paper, which is contrary: http://arxiv.org/abs/astro-ph/0506366
"Critical Examinations of QSO Redshift Periodicities and Associations with Galaxies in Sloan Digital Sky Survey Data"
Authors: Su Min Tang, Shuang Nan Zhang
(Submitted on 16 Jun 2005)

The second one, by Tang and Zhang, pretty much puts the hypotheses in the first, by Arp et al., to rest, doesn't it.

As far as I know, there have been no published papers making the case for 'discordant redshift' quasar-galaxy associations in the last five years or so (i.e. since SDSS DR3, say), are based on SDSS data^.

Detection of Cosmic Magnification with the Sloan Digital Sky Survey, a 2005 paper by Scranton et al., is a good, recent paper which shows that the way quasars and galaxies are distributed, on the sky, is consistent with what you'd expect if each were at distances from us close to what the Hubble redshift-distance relationship predicts (though this also assumes that General Relativity accurately describes the 'shape of space' over cosmological distances).

SDSS uses 200,000 quasars to confirm Einstein's prediction of cosmic magnification is an SDSS press release which describes this result (easier to read than the scientific paper!)

^ there's one, rather hilarious (if it weren't so sad) exception (that I know of)
« Last Edit: March 29, 2011, 10:56:24 pm by JeanTate »

JeanTate

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #32 on: March 29, 2011, 11:32:36 pm »
(...)

zutopian (and others), you might like to consider just how many quasars were unambiguously reported, in the astronomical literature, in 1983, 1990, and 1996, and how many were discovered by SDSS, the first astronomical results from which - the EDR - were not published until 2002. Given the amazing amount of new data from SDSS - in a form that is extremely uniform - perhaps the relative lack of papers since 2002 on galaxy-quasar associations carries a strong message?

I found a paper, which is from 2005: http://arxiv.org/abs/astro-ph/0501090
"Periodicities of Quasar Redshifts in Large Area Surveys"
Authors: H. Arp, C. Fulton, D. Roscoe
(Submitted on 6 Jan 2005)

Besides I found a paper, which is contrary: http://arxiv.org/abs/astro-ph/0506366
"Critical Examinations of QSO Redshift Periodicities and Associations with Galaxies in Sloan Digital Sky Survey Data"
Authors: Su Min Tang, Shuang Nan Zhang
(Submitted on 16 Jun 2005)

And now I found a "neutral" paper, which is from 2009: "Apparent discordant redshift QSO-galaxy associations"
Interestingly, the author is Martin Lopez-Corredoira: He is also one of the authors of the paper "Two emission line objects with z>0.2 in the optical filament apparently connecting the Seyfert galaxy NGC 7603 to its companion" (Jean Tate cited this paper in the OOTD article.).

"Apparent discordant redshift QSO-galaxy associations" http://arxiv.org/abs/0901.4534
Authors: Martin Lopez-Corredoira
(Submitted on 28 Jan 2009)

That's certainly an interesting paper, and as it's reasonably short and well-written, an easy read too.

Martin Lopez-Corredoira does make a very important point, albeit rather less strongly than I think he should have; namely, that calculations of statistical probability are really only meaningful with respect to some model ... and if the model is poorly specified (or, worse, not stated explicitly), the calculated numbers can be quite misleading (or worse) - the ULXs (ultra-luminous x-ray sources) are an example explicitly mentioned, but quasars (or QSOs) are more pertinent (models in which quasars are all the same kind of 'local' object - as originally proposed by Arp et al. - are clearly inconsistent with the data; models in which just some (an unspecified some) are are too vague to be even tested).

Also at play is the idea of non-cosmological redshift - that at least part of the observed redshift of an extra-galactic object is due to physical causes other than its (Doppler) motion or cosmological expansion of the universe. Martin Lopez-Corredoira said little on this, likely for good reason: proposals of any kind of non-cosmological redshift immediately run into the 'unexplain' problem I mentioned in my earlier post!

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #33 on: March 31, 2011, 08:54:24 am »
Quote
Please be informed, that there is a thread "Spiral galaxies containing another galaxy in their arm".
http://www.galaxyzooforum.org/index.php?topic=10591.0

In 2008, Ari Jokimaki, Harley "Skip" Orr, and David G. Russell (three amateurs) published "A Catalogue of M51 type Galaxy Associations" (link is to arXiv preprint abstract).

The first sentence in the abstract reads:
Quote
A catalog of 232 apparently interacting galaxy pairs of the M51 class is presented.

I do not know if any of these authors have done any follow-up - e.g. to see whether later SDSS DRs contain spectroscopy of the 'minor' members - but interestingly (in light of Bill Keel's recent Galaxy Zoo blog entry), this three-amateurs' paper is cited by Ron Buta, in "Galaxy Morphology"!

I found another related paper (2005) of one of the authors of the above paper (2008).
"Further Evidence for Intrinsic Redshifts in Normal Spiral Galaxies"
Authors: David G. Russell
(Submitted on 21 Mar 2005)
http://arxiv.org/abs/astro-ph/0503440

Besides I found a contrary paper from 2008:
"The origin of redshift asymmetries: How LambdaCDM explains anomalous redshift"
Authors: Sami-Matias Niemi, Mauri Valtonen
(Submitted on 24 Nov 2008 (v1), last revised 10 Dec 2008 (this version, v2))
http://arxiv.org/abs/0811.3968

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #34 on: April 02, 2011, 10:24:26 am »
I wonder, why there are given different redshifts for the same objects?  ???

At least for the quasar, the low zconf value tells us that the SDSS pipeline software couldn't get a unique redshift - and indeed, the lack of H-beta and [O III] emission way out in the red would be very odd for a quasar. At z=1.96, the strongest peak is not the Mg II 2800 A line, but the close pair of C IV lines emitted at wavelength 1549 A. Chasing down some of the NED references, it seems that published QSO catalogs likewise based on the SDSS spectra caught this, and matched the next peak with C III] 1909 (stronger than the [Ne V] assignment shown in the Explorer link). I have no idea why the pipeline should miss things previously assigned properly (but that has shown up before with some odd white dwarfs being mis-listed as quasars). I finally learned to pay close attention to zconf. NED seems to have a hierarchy of sources for listing redshifts (not that I know what it is) - there eventually came to be too many for the NED staff to actually cross-check visually before putting into NED.

I also looked now at the NED references and I guess, that the redshift in NED comes from this paper:
"Quasars in the COSMOS Field" http://arxiv.org/abs/astro-ph/0602315
M. K. M. Prescott (1), C. D. Impey (1), R. J. Cool (1), N. Z. Scoville (2) ((1) Univ. of Arizona, (2) CalTech)
(Submitted on 14 Feb 2006)
On page 11 there is given Table 3:
SDSS J100309.21+022038.3   z=1.967030*
* Independently confirmed by the 2dF quasar survey or subsequent SDSS spectroscopic follow-up.

And now I found out, that I am right, that the redshift in NED comes from the paper "Quasars in the COSMOS Field":
In NED there is given:
BASIC DATA for SDSS J100309.21+022038.3
Redshift                   :  1.967030 +/- 0.000762       ; 2006ApJ...644..100P

(EDIT-1)
When I tried to switch to DR8, there is however a blank image! *
It is a faint QSO: In DR7 there is given: PrimTarget TARGET_QSO_FAINT TARGET_SERENDIP_BLUE
There was a 2SLAQ survey, which has used imaging from the Sloan Digital Sky Survey (SDSS) and spectra from the 2dF-spectrograph on the Anglo Australian telescope to obtain redshifts for 13,000 luminous red galaxies with 0.4 < z < 0.7 and 6000 faint QSOs.
I remember a case: http://www.galaxyzooforum.org/index.php?topic=3874.msg525135;topicseen#msg525135
In DR7: - Classified as STAR, but the specClass is GALAXY! -TARGET_QSO_FAINT TARGET_SERENDIP_BLUE
In NED and Simbad there is given QSO!
In DR8 the class is QSO!

(EDIT-2) * It is just the area of the posted DR7 image, which is not shown in DR8!
I found a spectrum chart in DR8 for the faint Quasar SDSS J100309.21+022038.3, even though the area in DR8 is blank!
The redshift in DR8 is similiar like in NED:
DR8: z=1.964
NED: z=1.967
So SDSS revised the redshift: In DR8 there is given the revised redshift (in DR7: z=0.650).
DR8 spectrum chart: http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237653665259192578
« Last Edit: April 02, 2011, 10:50:33 am by zutopian »

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #35 on: November 14, 2011, 03:12:27 pm »
Today I quoted a post in the overlap thread and it reminded me of this OOTD: NED and DR7 say overlap, but DR8 says merger:

587731173306073231 


Stripe82 image:

http://www.galaxyzoo.org/examine/AHZ6000frt
http://cas.sdss.org/stripe82/en/tools/explore/obj.asp?id=8647475120884744681

According to DR7 and NED it is an overlap, but according to DR8 it is a merger!!! Strange!  ???
The redshift of the spiral galaxy is identical in DR7, DR8 and NED: z=0.052 http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237663543138910469
The elliptical has in DR7 and NED the redshift 0.209, but in DR8 it has redshift 0.052 (same as the spiral).

http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587731173306073230
http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237663543138910468




« Last Edit: November 14, 2011, 03:24:03 pm by zutopian »

RandyC

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #36 on: November 14, 2011, 05:57:57 pm »
I haven't seen many cases where we identified the DR7 redshift as being false, although here it is. The H-alpha lines is right at about where it should be at z=0.052. DR7 shows it in exactly the same place, at z=0.209. I think DR8 is right...it's a merger.

Today I quoted a post in the overlap thread and it reminded me of this OOTD: NED and DR7 say overlap, but DR8 says merger:
DR7 and Stripe82 images:
 
http://www.galaxyzoo.org/examine/AHZ6000frt
http://cas.sdss.org/stripe82/en/tools/explore/obj.asp?id=8647475120884744681
According to DR7 and NED it is an overlap, but according to DR8 it is a merger!!! Strange!  ???
The redshift of the spiral galaxy is identical in DR7, DR8 and NED: z=0.052 http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237663543138910469
The elliptical has in DR7 and NED the redshift 0.209, but in DR8 it has redshift 0.052 (same as the spiral).
 
http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587731173306073230
http://skyserver.sdss3.org/dr8/en/tools/explore/obj.asp?id=1237663543138910468
Randy

NGC3314

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #37 on: November 14, 2011, 06:51:46 pm »
I haven't seen many cases where we identified the DR7 redshift as being false, although here it is.

The data don't really support being categorical about "false" - the spectrum shows features at both redshifts (the emission lines at the lower z are clear, but Na D, Mg features around 5200 A emitted, and the 4000-A break with Ca lines are seen clearly from z=0.209. Even better, there are spectra from the centers of both galaxies to demonstrate this: northern southern (as just linked). The southern one shows contamination from the disk of the overlapping foreground spiral. DR7 and DR8 can clearly differ in which one they pick when two redshifts are matched in the spectrum - both are in the full data table, but only one is presented per object on the Explore screen.

RandyC

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #38 on: November 14, 2011, 07:07:47 pm »
Here is the best I could overlap the two spectra visually:
Randy

JeanTate

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #39 on: November 17, 2011, 09:17:03 pm »
I just replied to zutopian's post, in the other thread. I fully concur with what NGC3314 wrote.

RandyC, extracting meaning from spectra is not easy. I would say that a great deal of very high quality work has gone into building and testing the spectroscopic pipelines, and the SDSS team is to be praised - highly - for the terrific resource they've provided, for free, for everyone to use. The flip side of this is that you need to understand what the pipeline does, what its outputs are (all of them, not just the PNG image the Explore tool serves up), what the scientific/quantitative caveats are on the output redshift estimate, etc, etc, etc.

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #40 on: November 18, 2011, 08:05:30 pm »
NGC 4319 and Markarian 205 are also a controversial pair:

c_cld posted in the QSO thread the Hubble News Story:
http://www.galaxyzooforum.org/index.php?topic=3874.msg569487#msg569487
http://hubblesite.org/newscenter/archive/releases/2002/23/image/a/

Here is a journal article, which is contrary:
http://articles.adsabs.harvard.edu//full/1987ApJ...319..687S/0000693.000.html



zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #41 on: November 25, 2011, 07:24:38 pm »
"Evidence against non-cosmological redshifts of QSOs in SDSS data"
Authors: Sumin Tang, Shuang Nan Zhang
(Submitted on 16 Jul 2008 (v1), last revised 18 Jul 2008 (this version, v2))
Quote
In the unusual intrinsic QSO redshift models, QSOs are ejected by active galaxies with periodic non-cosmological reshifts, thus QSOs are generally associated with active galaxies, and certain structures will be revealed in the QSO redshift distribution. As the largest homogeneous sample of QSOs and galaxies, SDSS data provide the best opportunity to examine this issue. We review the debates on this issue, focused on those based on SDSS and 2dF data, and conclude that there is no strong connection between foreground active galaxies and high-redshift QSOs. The existence of two dips in the SDSS QSO redshift distribution at z=2.7 and 3.5 has recently re-ignited those controversial debates on the origin of QSO redshift. It also turned out that both dips are totally caused by selection effects and after selection effects have been corrected, the two dips disappear and no structure in the redshift distribution of SDSS DR5 sample. These results support that the reshifts of QSOs are cosmological.
http://arxiv.org/abs/0807.2641

JeanTate

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #42 on: December 20, 2011, 07:03:18 pm »
"Evidence against non-cosmological redshifts of QSOs in SDSS data"
Authors: Sumin Tang, Shuang Nan Zhang
(Submitted on 16 Jul 2008 (v1), last revised 18 Jul 2008 (this version, v2))
Quote
In the unusual intrinsic QSO redshift models, QSOs are ejected by active galaxies with periodic non-cosmological reshifts, thus QSOs are generally associated with active galaxies, and certain structures will be revealed in the QSO redshift distribution. As the largest homogeneous sample of QSOs and galaxies, SDSS data provide the best opportunity to examine this issue. We review the debates on this issue, focused on those based on SDSS and 2dF data, and conclude that there is no strong connection between foreground active galaxies and high-redshift QSOs. The existence of two dips in the SDSS QSO redshift distribution at z=2.7 and 3.5 has recently re-ignited those controversial debates on the origin of QSO redshift. It also turned out that both dips are totally caused by selection effects and after selection effects have been corrected, the two dips disappear and no structure in the redshift distribution of SDSS DR5 sample. These results support that the reshifts of QSOs are cosmological.
http://arxiv.org/abs/0807.2641

As far as I can tell, there's nothing* in this second, 2008, paper by Tang and Zhang that isn't also in the first, 2005, one (that you cited, in a post dated 26 March, 2011, earlier in this thread); if you think otherwise, zutopian, may I ask why?

In English - and, for all I know, many other languages too - there's a saying that one cannot ever "prove a negative". That applies in physics and astronomy too. Instead of proof, these branches of science use consistency (as in "consistent with") and synonyms, which always leaves the implication that there are other models, theories, hypotheses, etc which may be just as consistent ... and which may, when judged by other criteria, be better (in some sense).

However, as these branches of science are fundamentally quantitative, the degree of consistency can be - and should be, and mostly is - expressed in quantitative, or numerical, terms. For example, "For a quantitative assessment of the difference between the simulated and observed ∆Vr distributions, we performed the Kolmogorov-Smirnov test and found a 0.93% probability that the two were drawn from the same parent population", "delays ranging from ∆tBA ~ 27 to ∆tBA ~ 71 are not excluded at a 1 σ level", and "They also derived from linear regression with no prior on dY/dZ a result of 0.2609±0.0117, but it appears that their narrow metallicity range does not allow a slope to be determined." and "In the following we quantitatively examine this possibility and its effect."

In this respect, the Tang and Zhang papers are standard astrophysics! For example, "Clearly the periodicity at around △log(1 + zeff ) = 0.089 is highly significant at above 3.5σ level."

What, then, can we conclude from the Tang and Zhang papers; what sweeping generalization (to quote Budgieye) can we make?

Well, let me quote the conclusion (from the 2005 paper):
Quote
In summary, using samples from SDSS and 2QZ, we demonstrate that not only there is no periodicity at the predicted frequency in log(1 + z) and z, or at any other frequency, but also there is no strong connection between foreground active galaxies and high redshift QSOs. These results are against the hypothesis that QSOs are ejected from active galaxies or have periodic intrinsic non-cosmological redshifts.

Far from not 'proving there is no non-cosmological redshift in quasars', Tang and Zhang use the underwhelming words "These results are against the hypothesis that ..."!  :o

More important for this thread, however, are the clearly stated limits of their results: "the hypothesis that QSOs are ejected from active galaxies" and the hypothesis that QSOs "have periodic intrinsic non-cosmological redshifts".

In other words, their work says nothing (explicitly) about any other hypothesis/hypotheses concerning any non-cosmological component of QSO redshifts.

* concerning whether quasars (or QSOs, or AGNs) are at (or near) the distances implied by their redshifts and the Hubble relationship

egalaxy

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #43 on: January 17, 2012, 04:30:35 am »
Has anyone noticed this galaxy looks similar to M51?

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #44 on: September 09, 2012, 10:10:36 pm »
Warning: this topic has not been posted in for at least 120 days.


http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=588017702398328841
http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=588017702398263345

HST Newscenter:
News Release Number: STScI-2012-38,  September 6, 2012 09:00 AM (EDT)
Odd Galaxy Couple on Space Voyage
Quote
Astronomers have long tried to determine whether these two galaxies are actually interacting. Although looking at them from Earth they overlap, there is no evidence of new star formation, which would be one of the clearest signs that the two galaxies are indeed interacting. However, recent studies of very detailed Hubble images suggest the onset of some tidal interaction between the two.
M60 lies roughly 54 million light-years away from Earth; NGC 4647 is about 63 million light-years away.
http://hubblesite.org/newscenter/archive/releases/2012/38/image/a/
I am confused.: Why do they say, that there is apparently an "onset of some tidal interaction between the two", though those galaxies have different redshifts?  ???
NED:
MESSIER 060   z=0.003726
NGC 4647        z=0.004700     
« Last Edit: September 09, 2012, 10:25:01 pm by zutopian »