The Arp Atlas of Peculiar Galaxies, A Chronicle and Observer's
Guide by Jeff Kanipe and Dennis Webb, Willman-Bell, Inc., 2006.
by Duane Dunkerson
Nowadays they rarely put so much effort into providing the material,
text, and photographs for a book. The publisher is to be commended
for bringing the contributions of Mr. Kanipe and Mr. Webb to completion.
The book is of textbook size and weight. The pages are large, with
a white gloss. Only the covers are in color. The book was produced to
commemorate the 40th anniversary of the Atlas of Arp and its publication.
Arp, in any case, took photographs, and did not do CCD imaging.
He used negative plates so as to best show the details of the peculiarities
among the galaxies that he had selected. The photos were to be factual
and not necessarily pretty. The selection process by Arp, the authors
frankly state, had a psychological element involving what he thought
The selection, reproduced in this book in full with Arp's original
comments, was the result of the aforementioned selection process
and what he could find in the far reaches of space. From those places,
he began in 1962 to gather the photos taken with the 200 inch Palomar
telescope in California. His atlas was published in 1966. He was
aided by having his attention directed to interesting objects as
had been found by others such as Vorontsov-Velyaminov, Zwicky, Herzog,
Wild, Morgan and Mayall.
The number of objects recorded totaled 338. These objects were
not all entirely unknown to other astronomers. These usual objects
were felt to be so far into outlier land in regard to shapes of
galaxies, in general, that they were ignored. Arp thought the peculiarities,
though peculiar, were not necessarily fully unique. He felt the
peculiar could be put into categories according to shape or lack
of shape. The Atlas showed what he found.
Amateur astronomers have since observed them visually and obtained
CCD images. Amateur telescopes these days can be huge compared to
what amateurs routinely had in their possession in Arp's day. Arp's
objects are mostly faint or very faint. The amateurs mentioned in
this book conducted their activities with apertures in inches of
: 32,25,24,20,18,17.5,16,184.108.40.206,12.5,10, and 8. The lesser apertures
are generally used for imaging. The greater apertures can be for
imaging or also for visual observations. The results of the amateurs
are at the back of the book with many pages of their visual and
CCD imagery. There are maps and charts, observing highlights, notes
and visual impressions. The amateurs who completed the work are
If a pleasant diverging collection of objects was all there was
to it, then that would be the end of the story. But something else,
recounted in the authors' Chronicle, The Peculiar Universe of Halton
Arp, relates some diverging but not necessarily pleasant facts about
what was thought of Arp's Atlas beyond a cursory page-flipping appreciation
of these strange objects.
It all began in the library of the Palomar Observatory in 1966.
Arp had received a letter from Sérsic about three compact
radio sources close to NGC 6438, a bright and disturbed galaxy.
The letter prompted Arp to check further into locations of other
radio sources. After a few weeks, Arp had found 75 such sources
associated with over 30 different galaxies. Usually the associated
galaxies were elliptical in shape and not your run-of-the- mill
spiral galaxies. Also, some of the radio sources had much higher
redshifts than the associated galaxy. Therefore, Arp would reason
that the radio sources, some known as quasars, had intrinsic redshifts
not dependent on their distance from us.
All galaxies have redshifts of the spectral lines derived from
the atoms making up a galaxy. Edwin Hubble, in the 1920s, had shown
our Universe was not as local as we thought. The distance involved
to the far corners of the Universe was indeed "astronomical".
In addition, Hubble found that the further away from us was a galaxy,
the greater was its redshift. So how could the radio sources that
Arp was bringing to the attention of other astronomers be a worry
to the other astronomers?
The worry came because Arp also found a physical tie-in of filaments
or bridges of substances connecting a "near" galaxy and
some of the radio sources that had redshifts indicating that they
must be far away. Arp asserted in a 1966 Caltech colloquium that
quasars (the radio sources) were not remote. No, no said most astronomers,
those are chance alignments in the sky. The proximity is only apparent.
A distant quasar is placed in the sky so as to be seen as near a
Some astronomers wanted a debate about this matter. So in 1972,
John Bahcall and Arp debated. Most thought, or wanted to think,
Bahcall "won". Of Bahcall, Arp said - "
Bahcall, at that time a very ambitious kind of a guy, said he'd
do it. And it wasn't even his field then, but he was just ripe for
Others, not many, lined up behind Arp. Such notables as Fred Hoyle
and the Burbidges always supported him. They thought Arp deserved
to further explore the connections and contentions he had brought
up. Instead, Arp was denied use of any telescopes at Mt. Wilson
and on Palomar. He had been a staff astronomer at both places and
had been initially appointed to what was assumed to be a permanent
placement with these prestigious institutions then having the only
large enough telescopes to which he had had routine access.
Adding to the mix was the background concern that if the redshifts
of the quasars were not indicative of distant objects, then other
redshifts of other objects would be called into question and astronomers
had already decided for decades that the "cosmological"
redshifts showed that the Universe was derivative of a Big Bang.
This Big Bang had produced an expanding Universe as shown by recessional
redshifts for galaxies that supported the idea of an expanding Universe.
No, no said the overwhelming majority of astronomers, we want to
keep our Big Bang and the astrophysics that goes with it. Besides,
there are not that many oddball galaxies. Quasars have nothing to
do with them. Quasars near peculiar galaxies are statistically juxtaposed.
Leave the Hubble (and others) orderly classification of galaxies
alone. By 1981, representatives of this majority wanted Arp to lie
about what he was doing or get off his topics altogether. He would
have to "fundamentally redirect his efforts".
Arp noted galaxies are not just optical entities. There are also
x-rays, radio, gas, dust, and infrared components. Gravity was not
the only force shaping galaxies as magnetism could play a big role.
In 1987, Arp and Madore released A Catalogue of Southern Peculiar
Galaxies and Associations. There were 77,383 galaxies that they
had examined and 8% were peculiar in the usual personal and psychological
way. Also in 1987, Arp and Sulentic reported an appendage that appeared
to link NGC 4319, a Seyfert galaxy, and Markarian 205, a quasar.
No, no said the other astronomers, it is overlapping light contours
or an artifact. In 1983, Sulentic did more refined image processing
of Markarian 205. The result confirmed the earlier assertions by
himself and Arp. Arp in 1994, using ROSAT observations, found three
quasars of differing redshifts associated with Markarian 205. Then
there is NGC 7603 and NGC 7603B. How about M87 and its jet, known
since 1918? And M82 in a region of a large number of high-redshift
quasars? And still more are there fantastic shapes and displays
of super massive energies. Enough already! The mainstream astronomers
wanted Arp forced underground. He surfaced in Germany and San Diego
where he continued, as best he could, his research.
Arp was primarily an observer. He established nomenclature. Nevertheless,
he endorsed a theory of Hoyle and Narlikar of 1964 that accounted
for redshifts as not always involving velocity with special reference
to the recessional velocity as evidenced by cosmological redshifts.
Hoyle and Narlikar proposed a synthesis of Einstein and Mach. Narlikar
and Das in 1980 further refined the theory, one of variable mass.
The mass of an electron, for example, depended on how much of the
Universe it had interacted with or how long the electron had been
in existence. For Arp those intrinsic, discordant redshifts were
not dependent on velocity, they are related to time. The redshifts
were of the quantum world.
My Notion: Brownian motion can be demonstrated under a microscope
with milk diluted with water. The water molecules and their random
motion cause "the jitters" for the milk. Suppose the particles
of light are like the milk. The quanta units making up the quantum
world, not our particle world, are like the water molecules. There
is no preferred direction of effect of the quanta on the light unless
the direction of travel is in your direction - that confers a preferred
direction from your perspective. Remember the spectrum is not the
object. The spectrum comes to us over a great amount of time and
distance. The quantum bombardment in such a situation alters the
energy of the spectra. It makes for a reddening spectra. A snap
judgment would be that this is a variant of "tired light".
I prefer to call it battered light.