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NGC 7603 and  Strange  Quasars Cocorico !

NGC 7603 - Unknown source

This pair of galaxies in interaction appears in the catalog of Peculiar Galaxies of Halton Arp under the name ARP 92. These two galaxies have nothing in common, except for the existence of a bridge of matter which seems to connect them.

  1. The first one is a spiral galaxy for which z = 0,029.

  2. The second would be a Quasar for which z = 0,057.

  3. Their red shifts, being very different, their obvious nearness would be due only to a fortuitous alignment in the axis of vision.


But there are several


M. Lopez-Corredoira & Carlos M. Gutiérrez (astro_ph/0203466v227Mar2002)


But, some very recent observations revealed the presence, in the main axis of this bridge of matter, two objects (quasars) with absurd red shifts.

  •  Object 2, z = 0,243

  •  Object 3, z = 0,391

  • Bridge of matter, z = 0,030 (For whatever the zone of measurement)

It is very difficult to admit that this very specific alignment of all these objects is coincidental.

The hypothesis of the ejection of these "quasars" by the parent galaxy cannot be excluded. Well then it is necessary to find the explanation of the abnormal red shifts observed in this group of interactive objects.

Let us note that Halton Arp proposes the hypothesis that this abnormal red shifts would be the mark of young objects (which would have recently formed). By aging, these objects would find coherent red-shifts with their environments. This allows us to eliminate the argument which we often set against Arp, according to which we should observe a variation of red-shift in the bridges of matter.


  1. The object 1 would be a galaxy in interaction with NGC 7603.

  2. The bridge of matter would be constituted by stars, gas and dust undergoing the gravitational interactions of these two galaxies.

  3. Objects 2 and 3 would be bubbles of expanding ionized gas consequential to the explosion of two stars (Supernovae).

The bubble of gas is expanding fast, 5000 Km/s for example. The light emitted by the front of the bubble, in the direction of the observer is blue shifted. The light emitted by the back front is red shifted.
A spectral line, emitted in the red, Ha for example (6563 Å), is by this fact divided into halves. ( Fig.1).
And moreover if this bubble is at a cosmological distance, thus subjected to the "expansion" we can find a spectral line in the visible light (Front) and a infrared spectral line in the back Front.
The detection and the identification of these dual spectral lines allows to eliminate any ambiguity on the nature and the distance of this bubble.

Expanding Bubble of Hydrogen without dusty cloud(s) in the optical route.
Animation made by B. Lempel

But, and it is very likely considering the distance, the light emitted by the bubble is likely to have to cross clouds of gas and\or dusts ( Fig.2). The spectral line of the front "emitted" in the visible light is strongly or totally absorbed. On the other hand the spectral line "emitted" in the infrared, little absorbed, reaches the observer. The measure of distance, is then completely biased by the speed of expansion of the bubble.

Expanding Bubble of Hydrogen with dusty cloud(s) in the optical route.
Animation made by B. Lempel

The observer will have the illusion of observing a very brilliant and ultra-cosmological object. He will qualify it as Quasar in any good faith! And this, especially since all the spectral lines of the visible light will have been absorbed.


The characteristic spectral absorption lines of the dust should be detected, but it is not the case.


This objection, which was made for us by Halton Arp himself, is very solid. In fact it does not like if we notice that in the case of supernovae the dust can, by the effect of compression due to the shock wave, form a shell with pressure gradient of speed on the "surface" of the bubble of gas.
This pressure gradient of speed is thus associated in a set of side by side spectral absorptions lines. It is obviously necessary to add to it the effects of the inevitable turbulences in these mediums.
The summation of all these spectral lines gives a very wide band filter.

The absence of "variation" of red shifts in the bridges of matter that we had called as argument to reject the ideas of Halton Arp is thus explained. The idea that these abnormal red shifts are bound to young objects is totally validated.

It is evident that, in time, this effect tends to ease as a result of the dispersal of this bubble and dusts. The red shift returns to a "normal" value.

Documents to be consulted:

  1. Anomalous redshift companion galaxies: NGC 7603 - N.A. Sharp.

  2. Strong spectral variability in NGC 7603 over 20 years - W. Kollatschny, K. Bischoff & M. Dietrich.

  3. Two emission line objects with z > 0.2 in the optical filament apparently connecting the Seyfert galaxy NGC 7603 to its companion.  M. Lopez-Corredoira & Carlos M. Guttiérrez.

  4. The evolution of superbubbles and the detection of Lya in star-forming galaxies. - Guillermo Tenorio-Tagle, Sergey A. Silich, Daniel Kunth, Elena Terlevich and Roberto Terlevich - arXiv:astro-ph/9905324 v1 25 May 1999.

  5.    §  The 10/05/2014 a study about the red shifts of some atypical Quasars, including NGC 7603, was published:
    Expanding space, quasars and St. Augustine’s fireworks. O. I. Chashchina & Z. K. Silagadze - arXiv:1409.1708v1 [gr-qc].
    We are very glad that some scientists are finally focusing on these controversial topics.

Other documents:

  1. Catalog of "Peculiar Galaxies" by Halton Arp.
  2. The page of web site of Halton Arp.
  3. A BONE IN THE RED SHIFT (NGC 4319 & Mark 205)

 Last Release: 03/21/16 

Redshifts Quantization in Galaxy Clusters :