Quasar intrinsic red shift

[John Kierein]

Could some stars have intrinsic red shifts and be mistaken for quasars? Here's two examples of a quasar with a so-called "foreground" star. Could these perhaps be a binary star system with one of them having an intrinsic red shift?
Image on the left here:
http://www.rednova.com/images/images...ons/index.html

100,00th Hubble image here:
http://hubblesite.org/newscenter/new...eases/1996/25/

It might be worth revisiting these to see if there's proper motion between the quasar and the foreground star.

[snowflakeuniverse]

Hi John Kierein,
One of the physical charactorists of quasars are energy variations. These variations are "random" looking with cycles of a few days mixed in with cycles lasting weeks, months and even years. Stars can vary in brightness but nothing like the wild variations obseved in quasars.

Snowflake

[John Kierein]

Maybe. But the solar red shift is greatest during solar flares which are at times of variability. If the quasars are flaring stars they could well be variable, which produces the gamma rays and x-rays that ionize the atmosphere producing a larger Compton effect red shift. The proof of locality would be proper motion.

[antoniseb]

In order to show proper motion of the quasar you'd need two or more very small bright spots in the background galaxies in this image. Your idea is not a bad one, but I'm guessing that this particular image may not be the ideal one to work with.

[Nereid]

Could some stars have intrinsic red shifts and be mistaken for quasars? Here's two examples of a quasar with a so-called "foreground" star. Could these perhaps be a binary star system with one of them having an intrinsic red shift?

The quick answer is "No."

To see why, quickly, you only need to ask yourself the question "what sort of star could this 'quasar' be?" To find out, blueshift the quasar spectrum, look up your table of star spectra, and try to find a match.

You can't? OK, step two is to analyse the 'blueshifted' quasar spectrum as if the observed SED comes from a blob of hot, gravitationally confined, plasma/gas. Can you come up with a model which reproduces the observed (blueshifted) spectrum? Go for it John!

[peteshimmon]

There is a Canadian guy who has provided
evidence of Quasar proper motions. Google
should find it easily. And I found a
fascinating illustration of thousands of
quasar redshifts stacked in a colourful
diagram recently. (2df survey). The emmision
lines curved over for increasing redshifts but
I perceived many common absorpion lines
nicely vertical at zero redshift! Rather
embarrassing!

[VanderL]

Hi Peteshimmon,

Do you have any examples of high Z quasar spectra with non-shifted emission we could look at? I'm not sure it was a Canadian guy, but this MacMillan paper seems to be the one you are referring to. He shows a plot where proper motion of quasars do not fall off with higher redshift.

Cheers.

[ngc3314]

There is a Canadian guy who has provided
evidence of Quasar proper motions. Google
should find it easily. And I found a
fascinating illustration of thousands of
quasar redshifts stacked in a colourful
diagram recently. (2df survey). The emmision
lines curved over for increasing redshifts but
I perceived many common absorpion lines
nicely vertical at zero redshift! Rather
embarrassing!

Rather embarrassing for what? Even the least-mainstream ideas stipulate that quasar light shines through at least some of the gas in the Milky Way. For such lines as Lyman alpha, you can't look far in any direction before the Milky Way component becomes strong.

[upriver]

We define the term 'proper motion' as the apparent motion of a star across the celestial sphere at right angles to the observer's line of sight. This star chart contains the proper motion direction and value for 10 quasars from Luyten's 1969 list. These quasars are very faint, approximately 18 magnitude.
bottom of page...
http://laserstars.org/summary.html

http://laserstars.org/

[Nereid]

And I found a
fascinating illustration of thousands of
quasar redshifts stacked in a colourful
diagram recently. (2df survey). The emmision
lines curved over for increasing redshifts but
I perceived many common absorpion lines
nicely vertical at zero redshift! Rather
embarrassing!

Do you mean this kind of illustration (click on any of the 'Observed frame' plots, in Misc Pretty Plots)?

For whom are these 'many common absorption lines nicely vertical at zero redshift!' embarrassing? (Hint: it's not embarrassing for the 2dF astronomers! Why? see if you can determine the wavelength of these features)

[Nereid]

We define the term 'proper motion' as the apparent motion of a star across the celestial sphere at right angles to the observer's line of sight. This star chart contains the proper motion direction and value for 10 quasars from Luyten's 1969 list. These quasars are very faint, approximately 18 magnitude.
bottom of page...
http://laserstars.org/summary.html

http://laserstars.org/

I had difficulty following the links to the source data ... however, there's an intermediate table, in the laserstars website, which contains a list. Fortunately, there are error bars for each datum; unfortunately no units are given (I think we would be safe assuming arcsec, since the original data would be from ground-based, optical observations done in the 1960s and 1970s, with updates in the 1980s).

A quick scan turns up no proper motion greater than the error bars (and, if the error bars are 1 sigma, and the errors gaussian, we would expect there to be some, wouldn't we? Anyone want to have a go at making an OOM estimate of how many?).

But then, as VanderL's paper clearly shows, VLBI can give much more accurate estimates of observed proper motion than ground-based optical astrometry, and the PMs observed using VLBI are ~3 OOM smaller than those listed in the laserstars webpage (ignoring the error bars).

There is a Canadian guy who has provided evidence of Quasar proper motions.

You're new here pete, so you may not have picked up that this kind of statement is viewed by many members as quite disrespectful - if you've found something like this, you should provide us with a link (or, if a paper which isn't available online, a reference).

In both the ancestor fora (BA and UT), there were rules to the effect that proponents of an ATM idea should answer questions on their idea (and of course, an honest "I don't know" or "I don't have an answer" would be just as acceptable as "42 +/-3 Mpc", for example); it is likely the new BAUT rules will include something like this.

What is the evidence to which you refer?

[peteshimmon]

Sorry Neried, I'm in the net dark age with my
old browser and I cannot put links in. I was
interested in this subject and jumped in
gleefully with my recent findings. Anyway you
and upriver latched straight onto the items
and I did check that google would find the stuff.
I found the stacked spectra diagram in an
annual report of a British research agency, I
did not see it on the website so thanks. The
report also ha a full page picture of the same
technique with ordinary galaxies. No absorption
lines apparent here suggesting very strongly the
lines are intrinsic to the sources in the
quasar stacked spectra. And this was very
interesting to me. 30 years ago (ouch) I was
putting the idea about that quasars were
ordinary stars getting entangled with light from
external galaxies behind. No Net in those days,
our subversive ideas (or better descriptions of
the truth) were ciculated on duplicated
amateur publications. It was fun! But I got
nowhere of course! Then after a few years I
found a referance from 1967 where Hoyle and
others pointed out absorptions lines in two
quasars were the same as Greenstein found
in some white dwarfs! What was I getting
excited about, they already had evidence.
(Quasi-stellar objects, Burbidges, 1967, pg42).
I have for a few years wanted a composite
histogram of quasar absorptiion lines to see
if zero redshift lines are common but this
stacked spectra show the same thing much more
prettily.

[ngc3314]

The
report also ha a full page picture of the same
technique with ordinary galaxies. No absorption
lines apparent here suggesting very strongly the
lines are intrinsic to the sources in the
quasar stacked spectra.

That stack must not have included the emitted UV piece of the galaxy spectra. Galaxies which are bright enough in that range likewise show zero-redshift absorption lines; for analysis of FUSE spectra in the deep UV, they are extremely annoying. As an example, Fig. 3 of this paper shows the spectrum of NGC 604, the brightest star-forming region in M33, and the low-metallicity dwarf galaxy I Zw 18. The many absorption lines common to both are at almost exactly zero redshift, from Milky Way gas with slightly dofferent mean motion along these different lines of sight. For that matter, when they're bright enough to tell, galaxies also show the Lyman alpha forest at high redshift. Looking in the UV is a big deal because the only two absorption lines that one might see from interstellar gas in the visibile range, Ca II and Na I, are pretty weak to pick out from most galaxy spectra. A magnitude-limited survey does much better for quasars than galaxies in the UV, because quasars at a given redshift can be found which are much brighter than galaxies at that redshift.

[Nereid]

I found the stacked spectra diagram in an
annual report of a British research agency, I did not see it on the website so thanks. The report also ha a full page picture of the same
technique with ordinary galaxies. No absorption lines apparent here suggesting very strongly the lines are intrinsic to the sources in the
quasar stacked spectra.

On the 2dF page (the link in my post), you will find this .gif image (Whole Survey Stacks, Observed Frame ... features labelled ...). On that image you will see a circle with a (vertical) cross, which stands for 'telluric', meaning an (absorption) line from some atomic or molecular species in our own atmosphere. A careful check of the scale will show you that these seem to be just the 'many common absorption lines nicely vertical at zero redshift'.

Perhaps you can now tell us all why they are all 'at zero redshift'?

If I may make a suggestion? In cases like this, where you think you've found such a dramatic discovery in stuff that astronomers have been working with for decades, why not ask about it first (rather than advance with unseemly haste to declare 'embarrassment')?

[VanderL]

That stack must not have included the emitted UV piece of the galaxy spectra. Galaxies which are bright enough in that range likewise show zero-redshift absorption lines; for analysis of FUSE spectra in the deep UV, they are extremely annoying. As an example, Fig. 3 of this paper shows the spectrum of NGC 604, the brightest star-forming region in M33, and the low-metallicity dwarf galaxy I Zw 18. The many absorption lines common to both are at almost exactly zero redshift, from Milky Way gas with slightly dofferent mean motion along these different lines of sight. For that matter, when they're bright enough to tell, galaxies also show the Lyman alpha forest at high redshift. Looking in the UV is a big deal because the only two absorption lines that one might see from interstellar gas in the visibile range, Ca II and Na I, are pretty weak to pick out from most galaxy spectra. A magnitude-limited survey does much better for quasars than galaxies in the UV, because quasars at a given redshift can be found which are much brighter than galaxies at that redshift.

Hi ngc3314,

The article mentions strong absorption lines from the Milky Way, but it also reports almost no intrinsic absorption for the studied galaxy, why would there be a large difference in absorption lines between our galaxy and NGC 604?

Cheers.

[ngc3314]

Hi ngc3314,

The article mentions strong absorption lines from the Milky Way, but it also reports almost no intrinsic absorption for the studied galaxy, why would there be a large difference in absorption lines between our galaxy and NGC 604?

Cheers.

The major difference (strikingly visible in that far-UV spectrum) is in lines from molecular hydrogen, of which there are hundreds in this spectral window. Absorption from single-atom species shows up in both galaxies, slightly weaker in M33. Two things may contribute to the difference, both having to do with this measurement being taken looking straight into one of the most active star-forming regions in the Local Group. First, to do deep-UV measurements efficiently, one has to pick regions with little enough foreground dust so that its UV light isn't absorbed. Dust and dense molecular gas are closely associated, so that means we don't get the deep-UV background light from the areas that would show the striongest H2 absorption (and to see that in our galaxy, folks sometimes deliberately pay the price in exposure time to look at bright but dust-reddened stars). This effect is sometimes known as the UV bias. Another issue, also present around star-forming regions in our own galaxy, is that the escaping UV from the most massive stars will destroy (thorugh photodissociation) the molecules. In M33, this suggests that molecular gas is concentrated in a thin layer in which the stars have dissociated a hole almost all the way through the disk. Similarly deficits of H2 absorption are seen all the way out to high-redshift galaxies, likely for the same reasons. The UV bias is not as strong if we pick out single bright, small objects in random directions, like quasars or hot stars in the Milky Way's outer envelope or the Magellanic Clouds; the reason is that there is no structure in the gas across their images to favor light reaching us from one part over the other.

[peteshimmon]

Telluric eh! Must remember that. As I said I
saw the picture in a glossy publication and
did an instance common sense comparison with
the other picture of galaxy spectra. ngc3314
has adressed this point. And as you have noted
I am dated in my quasar knowledge. But back
in the seventies they were struggling to make
sence of absorption lines. I wondered if many
were zero redshift but it was not politic to
admit it. Ah well let them get on with it! Then
in the eighties I read of the "Lyman alpher
forest". I was a little bit outraged, you could
explain any set of lines with a stunt like that!
Was it a good deduction or the most
outrageous fudge in astronomical history. Well
I am older now and I suppose they know what they
are talking about. But it is almost evidence
for the old Steady State Theory, lots of little
clouds of hydrogen in intergalactic space. And
is it confirmed by seeing the same lines in
quasars close together in the sky? I will
henceforth avoid the word "embarrassing" as it
seems to be a red rag to a....

[ngc3314]

Telluric eh! Must remember that. As I said I
saw the picture in a glossy publication and
did an instance common sense comparison with
the other picture of galaxy spectra. ngc3314
has adressed this point. And as you have noted
I am dated in my quasar knowledge. But back
in the seventies they were struggling to make
sence of absorption lines. I wondered if many
were zero redshift but it was not politic to
admit it. Ah well let them get on with it! Then
in the eighties I read of the "Lyman alpher
forest". I was a little bit outraged, you could
explain any set of lines with a stunt like that!
Was it a good deduction or the most
outrageous fudge in astronomical history. Well
I am older now and I suppose they know what they
are talking about. But it is almost evidence
for the old Steady State Theory, lots of little
clouds of hydrogen in intergalactic space. And
is it confirmed by seeing the same lines in
quasars close together in the sky? I will
henceforth avoid the word "embarrassing" as it
seems to be a red rag to a....

Now, my family was all telluric...

The Lyman alpha forest has turned out to be a really important part of ideas on cosmic history, for rather different reasons that most thought for a decade or so. Initially the excitement was that the Lyman alpha clouds were protogalaxies, and their dramatic decrease in number with decreasing redshift meant that the gas was being progressively incorporated into galaxies. But simulations by Renyue Cen at Princeton made much more sense (including why the clouds didn't evaporate under their own pressure) if we consider this gas as the coolest part of a filamentary mass distribution which is densest in galaxy-rich regions (the same kind of cosmic web revealed by galaxy surveys and shown by structure-formation simulations). Most of it is too hot to produce much Lyman alpha absorption (i.e. the hydrogen is mostly ionized) - and this we now see in the He II and O VI forests (the latter being easily seen only at low redshifts before it gets confused with the more numerous Lyman alpha features). It was a big deal to see this idea supported by finding the features in He II, the oxygen lines in the far-UV, and most recently even higher-ionization X-ray absorption lines when a background quasar flares to give a strong enough background source for Chandra's spectrometer.

There is correlation, but not an exact match, between forest features seen in quasars close together on the sky. The best match (really close but not quite exact) is between gravitationally lensed images only a few arcsecond apart, where the line of sight never diverges by more than thousands of light-years.

What I find most amazing is that if our interpretation from these simulations is on the right track, not only is most of the ordinary baryonic matter found outside of galaxies, but most of the heavy elements may be as well, which suggests a truly remarkable interplay between galaxies and their surroundings back to very early times. The density is very low, which makes this stuff so hard to find, but it's spread through a vast region of space.

[peteshimmon]

Well if heavy elements are in these clouds then
my understanding that supernovae did it are
a bit dated (sniff). Just cant keep up.
Anyway I wonder if maps of quasars have been
produced showing their positions on the sky with
little circles around each showing the
different distance of each cloud in that
direction. Then if we speculate that nearer
clouds could have warmed up slightly, the
people producing maps of variations in the
Cosmic Background Radiation might see if they
correlate with the clouds. I know not if this
is a sensible idea but it is something to do!

[dirkbontes]

Could some stars have intrinsic red shifts and be mistaken for quasars?

As a consequence of proper motion? No.

Here's two examples of a quasar with a so-called "foreground" star.

Observe that these quasars each are also associated with respectively a disturbed galaxy and an elliptical galaxy. It is likely that they were expelled from these galaxies. The foreground stars are just that: coincidental.

It might be worth revisiting these to see if there's proper motion between the quasar and the foreground star.

Rather between the quasars and their associated galaxies. Halton Arp was interested in such proper motion and I suspect that a few astronomers are infrequently keeping a close eye on quasars for that reason. Time will tell.