Abell Clusters: Would You Like Them Here or There?
(with apologies to Dr. Seuss and Sam)
Mar 24, 2009

The image above is a composite of x-ray data (purple) from the Chandra X-ray Observatory and optical data (yellow) from the Hubble Space Telescope. The data is first processed by computers—a deliberate activity—and then again by human minds—an activity usually taken for granted. Just as the first process requires software, the second requires theories. And different theories, as different software, produce different interpretations.

The Chandra press release summarizes the expanding universe interpretation. The cluster is “2.3 billion light years away” and “massive.” It “shows signs of merging.” “Hundred-million-degree gas” emits x-rays. The “long arcs…are caused by gravitational lensing of background galaxies.” The cluster has “the largest system of such arcs ever found.”

Astronomer Halton Arp rejects the expanding universe theory but retains the idea that gravity is the principle force acting in the universe. He writes in Seeing Red:

"Are there other clusters of galaxies which look like the cluster at the center of our Local Supercluster, the Virgo Cluster? … Everyone believes there are many—and 4,073 of them are listed in the revised northern and southern Abell Catalogue. … Everyone—myself included—thinks instinctively of galaxy clusters as galaxies like our own seen at great distances."

But accumulating anomalies undermined Arp’s instinctive thought:

• Abell clusters have few normal galaxies. Most cluster galaxies are peculiar or distorted; many are “just star piles.”

• They tend to group around nearby active galaxies—just as Quasi-stellar Objects (QSO) do.

• Plus, they tend to occur in lines.

• Plus, the lines are the same ones marked out by QSOs and jets.

• Plus, the clusters are often paired across the nearby active galaxy with similar redshift values on each side—again just like QSOs.

• Cluster galaxies display no Hubble relationship. The redshift-apparent magnitude relation for normal galaxies is the basis for claiming a redshift-distance relation and hence an expanding universe. The expected dispersion is about 0.1 magnitude in brightness and 50 km/sec in Doppler-interpreted redshift. Abell clusters show up to 4 magnitudes of variation in brightness (corresponding to a variation in luminosity among member galaxies of 40 times) and up to 30,000 km/sec in velocities (requiring them either to be exploding instead of merging or to be stretched out over billions of light-years into Fingers of God pointing at the Earth).

• The x-ray radiation patterns around them show elongations toward and bridges to nearby active galaxies.

• If the arcs were gravitationally lensed background QSOs, their numbers should increase with fainter magnitude. Instead, the numbers level off. A survey of the lensed objects in this cluster whose redshifts have been measured shows that most fall within redshifts of 1.0 to 3.5, with a maximum at 2.5. Only a handful fall around 5.0.

Significantly, this cluster lies toward the southeast end of x-ray and radio filaments that twist through the Virgo Supercluster.

Arp, without ruling out plasma discharge effects, thinks that QSOs are ejected from active galactic nuclei. They gain mass, slow down, and grow brighter as they age (and decline stepwise in redshift) out to about 400 kiloparsecs (with redshifts around 0.3). Here they often fragment into BL Lac objects and start to fall back toward their parent galaxy. They continue to gain mass and hence to slow down, reducing their redshifts, as they become companions to the parent.

Therefore, Abell clusters are not “galaxies like our own seen at great distances” but small, immature galaxies and wisps of matter associated with nearby active galaxies.

Plasma cosmologists, without ruling out ejection effects, think QSOs and clusters are pinches in the polar component of a galactic circuit. There is little evidence that they move (or don’t): The sequence of properties with respect to distance from the active galaxy could be an effect of decreasing electrical stress. Abell clusters are simply not pinched as strongly or as coherently as QSOs.

Plasma pinches display both radial and concentric filamentation: Whether the filaments radiate in visible light depends on whether the current density places them in glow mode or dark mode discharge. The large number of concentric arcs in this cluster are striking, but unremarked are the number of galaxies whose disks are also aligned in concentric arcs: their axes would be aligned radially to the cluster’s center. Presumably, the galaxies are pinches in the radial Birkeland currents connecting the arcs with the center. Notably, some of these “arc aligned” galaxies are double, calling to mind the fact that Birkeland currents tend to pair up.

Many clusters show “radial arcs,” a bit of data that contradicts gravitational lensing theory but which theorists pass over as being “not fully understood.” Ring currents connected to the central electrode by a radial current are expected in plasma discharges. Examples range from the Dogleg Galaxy (NGC 1097) to the flux tube connecting Jupiter and the plasma torus (read: ring current) in which the satellite Io orbits. 

Not only are the clusters small and nearby, their galactic forms may not be differentiated into stars: Whether the spiral morphology of interacting Birkeland currents breaks up into smaller pinches depends on the electrical properties of the discharge. 

The circular morphology of this cluster is likely due to our viewing it along its axis. The Birkeland current (also called a field-aligned current) in which it is pinched probably has an hourglass shape. We see the concentric arcs and radial alignments because we are looking “into the funnel.” From the side, it would appear more like its smaller-scale cousin, the planetary nebula. The Bullet Cluster probably shows us the side view.

Needless to say, the x-rays are not emitted by “hot gas” but by plasma, that is by electrically accelerated electrons that spiral in the polar magnetic field (hence the “field aligned current”) and emit synchrotron radiation. The plasma may or may not be “hot,” that is, contain particles that randomly collide. 

In either case, Abell 1689 is near, dim, not massive, and not merging.

By Mel Acheson