Sunday, June 9, 2013

Discordant Redshift Excuses: But the Galaxies Show Connections!

As I demonstrated in the earlier posts in this series (see Discord for Discordant Redshifts. I., Discord for Discordant Redshifts. II.), the major geometrical arguments used by advocates of discordant redshifts are simply a result of perspective acting on a distribution of random points in
3-dimensional space, where redshift measurement of the point is proportional to its distance from the observer.

But the other major piece of evidence cited by discordant redshift advocates is that some of these apparently associated objects show actual connections between them.


Just how good are the 'connections' between discordant redshift objects, especially if we compare them to far more conclusive examples of connections between astronomical objects? 

Could the connections between the discordant objects be yet another example of coincidental alignment?

First of all, many of the objects show no connection at all, but below we'll take a look at some of the claimed cases for connections.

Arp 220

The image above, from "X-Ray-emitting QSOS Ejected from Arp 220", is an X-ray image generated from the ROSAT PSPC.  Here, the two high-z quasars (z=1.26 and z=1.25) are claimed to be ejected from Arp 220 (at z=0.018).  The 'trail' of X-ray spots is claimed to connect the high-redshift objects to Arp 220.  Note that the z=0.09 object, apparently part of this 'trail' seems to violate the theta-z = constant pattern.  If that makes it not part of the trail, then discordant reshift supporters are stuck with the claim that it is another of those 'low-probability' events, a chance alignment.  So either way, this configuration creates a problem.  We can view the optical region around the object at one of the sky survey sites.  You can retrieve a list of the objects in the field and optionally plot them.
Field around Arp 220 (at center).  Click to Enlarge
NGC 4258

Here's another image combining optical data with the ROSAT PSPC X-ray data, from "The pair of X-ray sources across NGC 4258: Its relation to intrinsic redshifts, ejection and quantization".  The claimed connection is the two quasars (concentric circular contours) to the left and right of the galaxy.

Another version of this graphic at Halton Arp's site.
Is there ANY hint of an actual connection between these three objects?

NGC 4319 & Markarian 205
One of the claimed strongest cases of connections between objects with radically different redshifts is the case of NGC 4319 and Markarian 205.  NGC 4319 is the barred-spiral galaxy in the center.  Markarian 205 is the brighter 'spot' in the upper right corner. 

You can see more images at the Hubble Heritage Project.  Additional material on this pair is available at NGC 4319 and Markarian 205 by Roger Knacke (Penn State Erie).

However, the claimed 'bridge' between the quasar and the galaxy appears only after significant image processing, such as in the image at the Discordancy Report web site.  The site even describes the technique used for generating this 'connection'.  The strange part about the detection of the 'bridge' above is that the image manipulation was apparently done on a 24-bit image in JPEG format of the earlier version of the image!  Application of the 24-bit color table reduces the sampling of intensities compared to the original data.  In addition, the JPEG image format compresses the image to a smaller file size by removing high-frequency, small-scale structures in the image, averaging them into larger scales.  This creates numerous artifacts that can become the basis of many strange claims after sufficient processing.  A lot has been written about the dangers of over-interpreting information in JPEG images due to the artifacts created by the compression:
To see even more examples of how cranks and crackpots 'discover' things in various images, check out Stuart Robbins' blog and podcasts covering the topic.

The bottom line is if you are doing detailed image analyses on JPEGs, odds are high that fine detail 'features' are artifacts of the compression and analysis.

I retrieved the dataset of the June 28, 1993 observation of these objects from the Hubble archive and viewed them in SAO Image DS9.  Note that these observations were made before the first Hubble servicing mission that repaired a number of optical problems with the telescope.  Below, I plot the upper right quadrant of the image from file w1940102t_c0f.fits, trying to stretch the color range sufficient to reveal any details between the galaxy and quasar.  I'll plot with two different color tables which should hopefully make it clear just how much detail there is in the pixel intensities alone.

 Rainbow color table applied to logarithmic+zscale mapping.   Click to view the full 800x800 image

Rainbow color table applied to logarithmic+zscale mapping.  This time data range is rescaled to 10-200.  Click to view the full 800x800 image.
Here I've applied the color table after weighting the original data with the zscale algorithm.  With the halo of random noise around the the galaxy (lower left) and quasar (upper middle) one sees a slight enhancement in the region between them, but you'd be hard pressed to claim an actual connection.  Both of these objects are extended, and for the galaxy it is especially noticeable as the blue 'speckles' against the violet background.  There may also be some additional enhancement created by the additional bright galaxy next to Markarian 205 (more easily visible in the second image).  With an overlap of fuzzy, extended objects (not point sources which would generate a gaussian distributed region), we expect to see an enhancement along the line between them, where the extended structure of both objects overlaps in the line-of-sight.  

Update: 6/10/2013:  I've been informed by the operator of Discordancy Report that their image analysis was performed on an uncompressed TIFF image of the 2002 observation.  However, even this does not make the observations immune from artifacts, or even over-interpretation of the data with sufficient processing.

As an additional example of how the feature in my experiment above may exist purely due to a judicious choice of color scaling, I'll add a screenshot raw plot of image intensity along a slice (green line) through the image that cuts between the quasar and the galaxy.  The high spikes in the graph below the image are either cosmic ray hits or hot pixels in the CCD.  If the connection between the two objects were real, you'd expect to see some kind of 'bump' or  rise in the graph above the noise where the feature crosses the green line.   However, it looks to be about the same level but for a slight increase on the left side as the slice gets closer to the galaxy.  Again, the reality of this 'connection' is questionable.
Screenshot of the data in DS9 with annotations.  Click to see full view.

Funny how the 'connections' between galaxies with these 'discordant redshift' quasars take so much work to see! 

Also consider that the space between galaxies is not completely empty.  When these objects are moving out from the parent galaxy, we should see evidence of some additional interaction along the path of motion.  Why don't we?  Why are so many of the 'connections' touted by Discordant Redshift advocates always at the limit of detectability?

Compare these claimed connections with...

REAL Stuff Ejecting from Galaxies
When we see stuff ejecting from galaxies, we really SEE STUFF.  Consider these cases where we combine the optical image of the galaxy with the radio image constructed from the synchrotron jets emission from the galactic center.  Compare the barely visible 'connections' claimed by supporters of discordant redshifts to real evidence of ejecting material in other wavelengths.
Centaurus A
APOD: Centaurus A: X-Rays from an Active Galaxy
APOD: Jets from Unusual Galaxy Centaurus A

Hercules A
APOD: Plasma Jets from Radio Galaxy Hercules A  

Not only are these jets obvious, we see they show very obvious interactions with their surroundings.  They are turbulent and twisted and as they move further from the galactic center, they spread and are slowed by interaction with the surrounding intergalactic medium.

These outflows of ionized plasma make an incredible impact on their surroundings as they move through the intergalactic medium.  The two examples above are strong evidence of actual material ejecting from galactic centers.

The discordant redshifts supporters have interactions between their objects, that are barely visible, when there is any interaction at all. 

So just how real can these claimed connections be?  Or are they, again, just the result of chance alignments?

Additional References
  • Bill Keel's galaxy resources.  I had the pleasure of meeting Dr. Keel at the CosmoQuest table at the recent Balticon where my talk included much of the content in this series of posts.  I especially enjoyed his story about a (former?) discordant redshift supporter.


Shannon Sims said...

I am not sure why you are referencing the Discordancy Report on your blog. It is not a creationist site nor am I a creationist. But please allow me to correct a few assumptions you made in your post when referencing my post concerning NGC 4319 and Markarian 205. I am quite familiar with JPEG compression artifacts and would not perform analyses of images in that format. I used the uncompressed TIFF image from the Hubble site to perform my image analysis and saved the resulting images in PNG format to avoid any compression artifacts. Also the original image I used was taken several years after the first HST service mission though the bridge is still visible even in pre-SM1 images, as your own analysis shows. I will update my post to include the information on image formats to hopefully avoid any future confusion.

W.T."Tom" Bridgman said...

Mr. Sims,

I have made an update to the main text above.

As for the creationism issue, many creationists invoke discordant redshifts as evidence of their particular cosmologies. Since discordant redshifts were long ago demonstrated an artifact of observational selection effects and biases (details documented in the other articles in the series), they are an appropriate subject for this blog. Your site had one of the best examples of producing the feature of interest.


Anonymous said...

Starting with the original Galaxy Zoo, the citizen scientists ('zooites') who participated discovered a large number of chance alignments. Astronomer Bill Keel coordinated a search for 'overlapping pairs', resulting in the publication of a catalog of them. More details on this website:

In one of my Object of the Day posts, in the Galaxy Zoo forum, I covered a similar topic, in a light-hearted way:

Perhaps the biggest problem for the 'discordant redshift' advocates is that spectra of the purported connections are consistent with two distinct redshift systems (the foreground and background galaxies), nothing in between.

Jean Tate

W.T."Tom" Bridgman said...

To Jean,

Excellent! Such an exploration of the datasets was on my wish list but it's nice to know someone has already done it.

The saddest part of the entire 'controversy' is that so much of the errors by discordant redshift supporters were due to a failure to think 3-dimensionally.


Anonymous said...

@Tom: the overlaps catalog focuses on foreground (large) spirals, backlit by (large) ellipticals or spirals. While there certainly are elliptical-elliptical overlaps, and foreground ellipticals overlapping background spirals, by far the greatest number of overlaps not in the catalog are large (or largish) foreground galaxies with small, high-redshift background galaxies. Such as the many discovered by zooites in the Andromeda Project (

Jean Tate