Author Topic: Wednesday, 16th March, 2011: a controversial galaxy  (Read 25976 times)

JeanTate

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #15 on: March 20, 2011, 10:07:41 pm »
I'm glad to see that this OOTD has attracted some interest.  :)

For all readers who are somewhat impressed by the apparent evidence for 'in reality' direct, physical associations between (low redshift) and (high redshift) quasars - other than things like gravitational lensing and absorption of light by (foreground) galaxies - may I suggest the simple concept of unexplain?

I don't recall who used this term - Carl Sagan? Isaac Asimov? - or made it popular, but it's both a very simple and very powerful one.

Basically it says that, while 'explaining' some astronomical image that seems to show a physical connection between a galaxy and a quasar (say) by proposing that such a connection actually exists may seem simple and straight-forward (and satisfying too), consider how much 'unexplaining' would have to be done.

For example, start with the spectra themselves, from which the redshifts were derived.

Today, we have very good explanations for how the spectra of galaxies and quasars appear they way they do, to us, here on Earth (or from near-Earth orbit, aboard the Hubble Space Telescope perhaps), involving extremely well-tested bits of physics. If a low-z galaxy were to be connected to a high-z quasar, by some sort of luminous bridge - according to a particular proposal about galaxy-quasar association - how would the features in the spectrum of the quasar (and galaxy) be explained? At the very least it would very likely involve some new physics, of a kind not yet found in any of the countless millions of physics experiments that have been conducted over the past several centuries. Of course, there's nothing wrong with proposing some new physics, but a huge challenge in any such proposal is to explain all of the current physics, in a fully consistent way.

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?

JLConawayII

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #16 on: March 21, 2011, 02:41:44 am »
Interesting post.  The two galaxies in the image look completely unrelated to me, just looking at it.

Budgieye

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #17 on: March 21, 2011, 06:01:45 am »
Interesting OOTD!

It has been a while since I've used the Wolfram redshift calculator
 so I'm itching to try this one.

Us                   0
Big Spiral       394 million light years away
Little Round    770 million light years away

So, Little Round is twice as far away as Big Spiral

A stream of matter connecting Big Spiral to Little Round
is just as unlikely as
a stream of matter connecting Us to Big Spiral.

The little yellow blobs in the stream of matter are far-off galaxies, their colour redshifted into yellow.
2870 million light years away and
4200 million light years away
or, approximately a quarter of the way across our universe.
« Last Edit: March 21, 2011, 06:41:21 am by Budgieye »

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #18 on: March 21, 2011, 06:08:22 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

CGCG 036-024 has no spectrum in SDSS. In NED there is given z=0.04416. On the Examine page of the Hubble Zoo image there is given Redshift: 0.181000.
"Near" to it , I found a quasar: http://cas.sdss.org/dr7/en/tools/explore/obj.asp?id=587727944034287847
In SDSS there is  given a spectrum z=0.650 (zconf 0.777801), but in NED there is given z=1.967030.

I wonder, why there are given different redshifts for the same objects?  ???
« Last Edit: March 21, 2011, 06:11:07 pm by zutopian »

NGC3314

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #19 on: March 21, 2011, 06:51:34 pm »
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.

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #20 on: March 21, 2011, 07:45:28 pm »
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.
« Last Edit: March 21, 2011, 07:53:14 pm by zutopian »

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #21 on: March 22, 2011, 11:08:40 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!

« Last Edit: March 22, 2011, 09:19:27 pm by zutopian »

c_cld

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #22 on: March 23, 2011, 09:19:00 am »
in new paper submission: arXiv:1103.4134v1: Shining Light on Merging Galaxies I: The Ongoing Merger of a Quasar with a `Green Valley' Galaxy

Quote from: Robert L. da Silva
Serendipitous observations of a pair z = 0.37 interacting galaxies (one hosting a quasar) show a massive gaseous bridge of material connecting the two objects. This bridge is photoionized by the quasar (QSO) revealing gas along the entire projected 38 kpc sightline connecting the two galaxies. The emission lines that result give an unprecedented opportunity to study the merger process at this redshift...
quasar/galaxy pairs with QSO-photoionized tidal bridges such as this one offer unique insights into the galaxy properties

QSO host galaxy 1237663543138320633 SDSS J204956.61-001201.7
companion "green valley" galaxy  1237663543138320634 or 1237666661283987793


no redshift discrepancy  ;D  ;D

NGC3314

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #23 on: March 23, 2011, 02:51:55 pm »
That latest paper - on the QSO ionizing a tidal tail and gas in the companion, at z=0.37 - is a striking instance of something we see in the Voorwerpje sample (and in fact I just added that reference to the draft). The easiest way to put a lot of cold gas in a position to be ionized by an AGN that far out seems to be a galaxy encounter pulling out a gas-rich tidal stream. If we knew enough of these, they might give us a way to look at the angular pattern of emerging radiation, seeing which parts of the gas stream are and are not ionized.

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #24 on: March 23, 2011, 07:48:41 pm »
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

Alice

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #25 on: March 23, 2011, 10:55:32 pm »
I remember when that thread was started up. Bill (NGC3314) was one of the first to post in it. There is no evidence that these galaxies actually do "contain another spiral galaxy in their arm" - they are mostly overlapping galaxies.

Nice parallel to this OOTD though. :)
« Last Edit: March 23, 2011, 11:14:38 pm by Alice »

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #26 on: March 24, 2011, 07:00:51 pm »
Here are the Stripe82 images of the OOTD:


On the b/w Stripe82 image it looks as if 587731186736300210 (z=0.077)/2MASX J23190110+0016516 is also connected with NGC 7603:

http://www.galaxyzoo.org/examine/AHZ6000ili
8647475121437343795

« Last Edit: March 24, 2011, 07:28:13 pm by zutopian »

JeanTate

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #27 on: March 25, 2011, 03:17:38 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"!

zutopian

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #28 on: March 26, 2011, 05:38:49 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)

c_cld

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Re: Wednesday, 16th March, 2011: a controversial galaxy
« Reply #29 on: March 26, 2011, 06:04:47 pm »
Could I suggest a possible QSO candidate bridging a galaxy I posted in "Peas" thread http://www.galaxyzooforum.org/index.php?topic=3638.msg538586#msg538586
Object in DR8 1237655369825780205 or DR7 588011123577586125 photoZ  0.25896
and ACS/WFC G800L GRISM 1D spectrum (fits file) HAG_J123616.05+621927.8_J8HQAAKAQ


That latest paper - on the QSO ionizing a tidal tail and gas in the companion, at z=0.37 - is a striking instance of something we see in the Voorwerpje sample (and in fact I just added that reference to the draft). The easiest way to put a lot of cold gas in a position to be ionized by an AGN that far out seems to be a galaxy encounter pulling out a gas-rich tidal stream. If we knew enough of these, they might give us a way to look at the angular pattern of emerging radiation, seeing which parts of the gas stream are and are not ionized.