Redshift z

[Pluto]

G'day Modest

 

That would be fun.

 

 

Thank you modest for the ink

 

About the SDSS

What is the Sloan Digital Sky Survey?

 

SkyServer: About the SDSS

 

The SDSS addresses fascinating, fundamental questions about the universe. With the survey, astronomers will be able to see the large-scale patterns of galaxies: sheets and voids through the whole universe. Scientists have many ideas about how the universe evolved, and different patterns of large-scale structure point to different theories. The Sloan Digital Sky Survey will tell us which theories are right - or whether we will have to come up with entirely new ideas.

 

The SDSS will make the largest map in human history. It will give us a three-dimensional picture of the universe through a volume one hundred times larger than that explored to date. The SDSS will also record the distances to 100,000 quasars, the most distant objects known, giving us an unprecedented hint at the distribution of matter to the edge of the visible universe. The SDSS is the first large-area survey to use electronic light detectors, so the images it produces will be substantially more sensitive and accurate than earlier surveys, which relied on photographic plates. The results of the SDSS are electronically available to the scientific community and the general public, both as images and as precise catalogs of all objects discovered. By the end of the survey, the total quantity of information produced, about 15 terabytes (trillion bytes), will rival the information content in all the books of the Library of Congress.

 

You can google the Universe. If that is so when all this data is collected than it will become very interesting.

[Little Bang]

A Fine-tooth Comb To Measure The Accelerating Universe

 

Doesn't this method presume that wave lengths don't get longer with the expansion of the universe?

[modest]

A Fine-tooth Comb To Measure The Accelerating Universe

 

Doesn't this method presume that wave lengths don't get longer with the expansion of the universe?

 

Not at all. They use a spectrograph to split light into its spectrum then identify the absorption lines of certain elements. When light is redshifted and the wavelength increased then these absorption lines move. By comparing the spectrum of distant objects to a reference spectrum here on earth, it is possible to determine how much the light has redshifted. So, rather than presuming light doesn't get longer they presumes that light does.

 

Unless I'm missing where you think they made the bad assumption...

 

~modest

[Pluto]

G'day from the land of ozzzzzzzz

 

How do they account for the intrinsic redshift when they are calculating the distance?

[modest]

How do they account for the intrinsic redshift when they are calculating the distance?

 

They most certainly do not.

 

Intrinsic redshift - Wikipedia, the free encyclopedia

 

~modest

[Little Bang]

Thank you Modest for clearing that up.

[Pluto]

G'day from the land of ozzzzzzzzzz

 

Modest said

 

They most certainly do not.

 

Intrinsic redshift - Wikipedia, the free encyclopedia

 

 

Modest you know the workings of jet formation and the intrinsic redshift properties that bipolar jets have.

 

How can you say most certainly do not?

 

[astro-ph/0510747] Double Lobed Radio Quasars from the Sloan Digital Sky Survey

 

Double Lobed Radio Quasars from the Sloan Digital Sky Survey

 

Authors: W. H. de Vries (1,2), R. H. Becker (1,2), R. L. White (3) ((1) University of California, Davis, (2) IGPP, Lawrence Livermore National Laboratory, (3) Space Telescope Science Institute)

(Submitted on 26 Oct 2005)

 

Abstract: We have combined a sample of 44984 quasars, selected from the Sloan Digital Sky Survey (SDSS) Data Release 3, with the FIRST radio survey. Using a novel technique where the optical quasar position is matched to the complete radio environment within 450", we are able to characterize the radio morphological make-up of what is essentially an optically selected quasar sample, regardless of whether the quasar (nucleus) itself has been detected in the radio. About 10% of the quasar population have radio cores brighter than 0.75 mJy at 1.4 GHz, and 1.7% have double lobed FR2-like radio morphologies. About 75% of the FR2 sources have a radio core (> 0.75 mJy). A significant fraction (~40%) of the FR2 quasars are bent by more than 10 degrees, indicating either interactions of the radio plasma with the ICM or IGM. We found no evidence for correlations with redshift among our FR2 quasars: radio lobe flux densities and radio source diameters of the quasars have similar distributions at low (mean 0.77) and high (mean 2.09) redshifts. Using a smaller high reliability FR2 sample of 422 quasars and two comparison samples of radio-quiet and non-FR2 radio-loud quasars, matched in their redshift distributions, we constructed composite optical spectra from the SDSS spectroscopic data. Based on these spectra we can conclude that the FR2 quasars have stronger high-ionization emission lines compared to both the radio quiet and non-FR2 radio loud sources. This is consistent with the notion that the emission lines are brightened by ongoing shock ionization of ambient gas in the quasar host as the radio source expands.

 

The nature of any star in what ever form would have an intinsic redshift/blue shift.

[Southtown]

Haha awesome stuff! Thx you.

[coldcreation]

A Fine-tooth Comb To Measure The Accelerating Universe

 

Doesn't this method presume that wave lengths don't get longer with the expansion of the universe?

 

One of the interesting (very interesting) features of the project mentioned in the link above is CODEX.

 

One of the ambitious project to be realised with the E-ELT' date=' called CODEX, aims to measure the recently discovered acceleration of the universe directly, by following the velocities of distant galaxies and quasars over a 20-year period. This would let astronomers test Einstein's general relativity and the nature of the recently discovered, and mysterious, dark energy.

 

"We have to measure the movement of these distant galaxies to a few centimetres per second, and follow this over decades. These speeds are barely faster than a snail's pace, and the laser frequency comb is absolutely crucial for this," says team member Antonio Manescau, from ESO.[/quote']

 

There are several other links specifically on this subject online (Google E-ELT CODEX). I will read up on it before comenting further. But as I understand so far this is a crucial test: not just to determine the actual velocity of SNe through motion (something never done before) but to see if there is any motion (expansion) at all.

 

Measuring a consistent change in the redshift over time (20 years or more) for a variety of objects in a sample (or several SNe Ia) would be very strong evidence in favor of expansion and acceleration of expansion. However, if it is found, 20 years from now, that the redshift of the sample has not evolved then it is evident that redshift z would have to be attributed to another cause, i.e., something other than a receeding motion.

 

Again, if my interpretation of the CODEX project (without having read anything but the above text) is correct, this will be the first time that actual motion will be detectable. Prior to this technology, it would have been impossible to determine if z was due to motion or some other cause, since the acuracy of measurment was insufficient to determine motion over time, even since the 1920s. So 20 years is a very short time, indeed, to have to wait for the results.

 

Prior to the CODEX project my hopes were pinned on the future JWST observations, to determine if expansion was real, but now...

 

Cool.

 

 

CC

[Pluto]

G'day from the land of ozzzzzzzzzz

 

Sometime the work of others puts it in words batter than I can.

 

 

On quasar host galaxies as tests of non-cosmological redshifts

On quasar host galaxies as tests of non-cosmological redshifts

 

Abstract

 

Despite a general consensus in the astronomical community that all quasars are located at the distances implied by their redshifts, a number of observations still challenge this interpretation, possibly indicating that some subpopulation of quasars may harbour significant redshift components not related to the expansion of the Universe. It has been suggested that these objects may have been ejected from local galaxies and are likely to evolve into new galaxies themselves. Here, a test of such exotic scenarios is proposed, based on the spectral energy distribution of the galaxies hosting quasars with suspected ejection origin. Provided that the time-scales over which the ejected objects manifest themselves as quasars is short, one would in the framework of the ejection scenarios expect to find either no quasar host galaxy, a pseudo-host consisting of gas ionized by the quasar, or a host galaxy consisting of young stars only. It is argued that the spectral energy distributions corresponding to the last two options should differ significantly from that of most quasar host galaxies detected at low redshift so far, thus providing a potential test of the claimed existence of ejected quasars. A minimal implementation of this test, involving optical and near-infrared broad-band photometry, is suggested.

 

Observations of many images indicate the above. Jets from local and afar.

[modest]

Modest you know the workings of jet formation and the intrinsic redshift properties that bipolar jets have.

 

How can you say most certainly do not?

 

...

 

The nature of any star in what ever form would have an intinsic redshift/blue shift.

 

It would seem intrinsic redshift is different from what you think it is:

 

Intrinsic redshift is the hypothesis from various non-standard cosmologies that a significant portion of the observed redshift of extragalactic objects (e.g. quasars and galaxies) may be caused by a phenomenon other than the traditionally accepted redshift mechanisms – (1) cosmological redshift; (2) Doppler redshift; and (3) gravitational redshift.

 

Intrinsic redshift - Wikipedia, the free encyclopedia

 

~modest

[Pluto]

G'day Modest

 

 

Intrinsic redshift - Wikipedia, the free encyclopedia

 

Since radio galaxies have much lower observed redshifts than the quasars, the excess quasar redshift could not have a Doppler origin from high ejection velocities because there are no blueshifted quasars with respect to the objects from which they are proposed to have originated. Since the traditionally accepted redshift mechanisms are not capable of explaining the large observed redshifts of quasars if they are associated with relatively nearby radio galaxies, Arp concluded that most of the observed redshift of the quasars must be caused by an unknown non-cosmological or "intrinsic" mechanism.

 

Other astronomers that have also published research supporting the hypothesis that at least some quasars are local rather than at cosmological distances include:

 

Geoffrey Burbidge who has been a long-time supporter of the local quasars hypothesis.

Morley Bell who studied the distribution of quasars around the Seyfert galaxy NGC 1068.

Lopez-Corredoira and Gutierrez who have studied the apparent association of higher redshift objects around NGC 7603 and the NEQ3 system.

 

 

How do you differentiate between a galaxy and a quarsar?

 

What is a non -cosmological compared to a cosmological?

 

What possible intinsic mechanism could there be and not be cosmological?

[modest]

"Cosmological" in the context above means 'because of cosmological expansion'. Intrinsic redshift is a dead theory once proposed by Halton Arp. It has nothing to do with this.

 

~modest

[Pluto]

G'day modest

 

Something does not add up with the logic.

 

You said

 

"Cosmological" in the context above means 'because of cosmological expansion'. Intrinsic redshift is a dead theory once proposed by Halton Arp. It has nothing to do with this.

 

and yet

 

I read links like

Title Query Results

 

and

eg.

 

On quasar host galaxies as tests of non-cosmological redshifts

On quasar host galaxies as tests of non-cosmological redshifts

 

 

The properties of the compact matter and the jets they produce must influence the redshift in either red or blue shifts. This in turn would influence the data on quarsars.

[modest]

G'day modest

 

Something does not add up with the logic.

 

You said...

 

and yet...

 

The properties of the compact matter and the jets they produce must influence the redshift in either red or blue shifts. This in turn would influence the data on quarsars.

 

Aye, mate. I think our discord stems from this:

"non-cosmological" is not equal to "intrinsic"

 

As wikipedia says:

Intrinsic redshift is the hypothesis from various non-standard cosmologies that a significant portion of the observed redshift of extragalactic objects (e.g. quasars and galaxies) may be caused by a phenomenon other than the traditionally accepted redshift mechanisms – (1) cosmological redshift; (2) Doppler redshift; and (3) gravitational redshift.

 

Intrinsic redshift - Wikipedia, the free encyclopedia

 

So, we might consider that QSOs are in gravity wells and therefore locally (local to the QSO) redshifted. Such would not be intrinsic (as I would define the term... and wiki too), but it would be non-cosmological.

 

What you say about jets also may add to or subtract from redshift via local doppler shift. This would be non-cosmological, but not necessarily intrinsic--all depends on how we define our terms.

 

Halton Arp's variable mass theory is most certainly intrinsic and non-cosmological. This is how I would use the term and how wiki uses it. It refers to alternative theories of redshift - not alternative theories of quasar redshift data. This is an important distinction that has caused us problems of communication.

 

The question remains... what causes the high redshift values of QSOs? There was a lot of questions about this in the 50's - 80's. With addition data from better ground-based telescopes and with Hubble we are less troubled by this question and fringe theories like Arp's no longer seem sane. We now know QSOs have host galaxies. We also know there are galaxies that are not in any way associated with QSOs that are highly redshifted. We know QSO-host-galaxies have an angular size that is expected from a very distant, highly redshifted source. The notion that QSOs are local and have intrinsic redshift no longer makes any observational sense.

 

In other words, observation has killed theories of intrinsic redshift.

 

~modest

[Pluto]

G'day modest

 

Thanks mate,

 

I will keep reading until I get it into my thick scull.

 

 

Studies of intrinsic properties of gamma ray bursts detected by the HETE-II sate

Studies of intrinsic properties of gamma ray bursts detected by the HETE-II satellite

 

 

The results imply strong evidence for luminosity evolution with redshift and are consistent with prior studies based on BATSE bursts. Concordance cosmology (O L = 0.7, O M = 0.3, H 0 =70 km s -1 Mpc -1 ) is assumed throughout the analysis. Effects of log-normal errors in the redshifts are estimated using Monte-Carlo methods. Results indicate that a fraction close to 10% of GRBs are to be expected at high redshifts (> 5) in consonance with theoretical predictions of high- redshift Swift detections. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)

 

I think I may have to give myself another few years of reading.

[Pluto]

G'day modest

 

This link maybe of interest to you

 

A study of quasar proximity in OVI absorbers at z = 2-3

A study of quasar proximity in OVI absorbers at z = 2-3

 

 

In summary, we find no firm evidence that quasar radiation influences the weak OVI absorbers, suggesting they are collisionally ionized rather than photoionized, possibly in the multiphase haloes of foreground galaxies. Non-equilibrium collisional ionization models are needed to explain the low temperatures in the absorbing gas, which are implied by narrow-line widths (b < 14kms-1) in over half of the observed OVI components.