My views on Cosmology and Physics
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Book by David Michalets
This is section 7 of 18.
The web page series for Distant Spectral Shifts is based on my book Cosmology Crisis Cleared.
The Data Set containing galaxy data identifies the type of every galaxy in the list.
7.1 Definition of the types
Wikipedia offers a detailed explanation of them.
An excerpt from Galaxy morphological classification:
Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance. There are several schemes in use by which galaxies can be classified according to their morphologies, the most famous being the Hubble sequence, devised by Edwin Hubble and later expanded by Gérard de Vaucouleurs and Allan Sandage. However, galaxy classification and morphology are now largely done using computational methods and physical morphology.
The de Vaucouleurs system retains Hubble's basic division of galaxies into ellipticals, lenticulars, spirals and irregulars. To complement Hubble's scheme, de Vaucouleurs introduced a more elaborate classification system for spiral galaxies, based on three morphological characteristics:
Bars. Galaxies are divided on the basis of the presence or absence of a nuclear bar. De Vaucouleurs introduced the notation SA to denote spiral galaxies without bars, complementing Hubble's use of SB for barred spirals.
He also allowed for an intermediate class, denoted SAB, containing weakly barred spirals. Lenticular galaxies are also classified as unbarred (SA0) or barred (SB0), with the notation S0 reserved for those galaxies for which it is impossible to tell if a bar is present or not (usually because they are edge-on to the line-of-sight).
Rings. Galaxies are divided into those possessing ring-like structures (denoted '(r)') and those without rings (denoted '(s)'). So-called 'transition' galaxies are given the symbol (rs).
Spiral arms. As in Hubble's original scheme, spiral galaxies are assigned to a class based primarily on the tightness of their spiral arms. The de Vaucouleurs scheme extends the arms of Hubble's tuning fork to include several additional spiral classes:
Sd (SBd) - diffuse, broken arms made up of individual stellar clusters and nebulae; very faint central bulge
Sm (SBm) - irregular in appearance; no bulge component
Im - highly irregular galaxy
Most galaxies in these three classes were classified as Irr I in Hubble's original scheme. In addition, the Sd class contains some galaxies from Hubble's Sc class. Galaxies in the classes Sm and Im are termed the "Magellanic" spirals and irregulars, respectively, after the Magellanic Clouds. The Large Magellanic Cloud is of type SBm, while the Small Magellanic Cloud is an irregular (Im).
The different elements of the classification scheme are combined — in the order in which they are listed — to give the complete classification of a galaxy. For example, a weakly barred spiral galaxy with loosely wound arms and a ring is denoted SAB(r)c.
Visually, the de Vaucouleurs system can be represented as a three-dimensional version of Hubble's tuning fork, with stage (spiralness) on the x-axis, family (barredness) on the y-axis, and variety (ringedness) on the z-axis. [Reference:
This excerpt is not the complete topic but covers the important details. This is enough to understand most of the galaxies listed in my galaxy data set.
Note: AGN is sometimes found in descriptions of galaxies or quasars. AGN is short for Active Galactic Nucleus.
AGN refers to an electromagnetic entity in the nucleus generating intense radiation spanning a broad range of wavelengths from X-ray to radio. An AGN is a source of synchrotron radiation, a term explained in section Light.
Internal mechanisms in galaxies were covered in my earlier books and are not completely repeated here. This book is about correctly measuring the velocity of galaxies from on or near the Earth, not about their AGN.
7.2 Seyfert Galaxy
A Seyfert galaxy is a special type of a spiral galaxy.
Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei (very luminous, distant, and bright sources of electromagnetic radiation) with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.
Seyfert galaxies account for about 10% of all galaxies and are some of the most intensely studied objects in astronomy, as they are thought to be powered by the same phenomena that occur in quasars, although they are closer and less luminous than quasars. [Reference:
This description reveals the lack of understanding of the mechanisms driving the behaviors of a spiral galaxy. A spiral galaxy model defined by Donald Scott was described in an earlier book. A very brief explanation summary here is the spiral galaxy has an axial electrical current from its host cluster. This current generates the galactic magnetic field. The magnetic field generates the Lorentz force driving the disk rotation because stars have a positive charge.
At the galactic core, the current both bends and splits to provide a current out each spiral arm to deliver a current to the stars there.
When an electric current's path changes due to a magnetic field, the result is synchrotron radiation. The velocity of the current drives the peak frequency in the synchrotron radiation distribution of energy. A very fast current achieves X-ray wavelength energy. Nearly every spiral galaxy has its point source of X-rays in its core from this mechanism. The electric current along the galaxy's axis bends to go out the spiral arms. This axial current also generates the galactic magnetic field driving the disk rotation.
There is absolutely no dark matter. Any place where this invisible, undetectable entity is proposed, there is a magnetic field being ignored. [not in the book: Cosmology has yet to accept the basics of plasma physics, despite Hannes Alfven getting the 1970 Nobel Prize in Physics, for his work improving that branch of physics.]
7.3 Galaxy examples.
The following are spectrum samples from several Messier objects. These are all from NED, or the NASA Extragalactic Database. [Reference:
That site offers a simple display with a sequence of:
1) The object's name is entered into an entry field,
2) Click on Go,
3) Wait for the object to be found. Acceptable names can include an NGC number, or another name. For example, either M31 or NGC 224 gets the Andromeda galaxy.
Some objects have more pages of data than others.
The Spectra tab / selection shows the number of spectra recorded for the object. At the top right is the spectrum band, like Optical or Mid-IR, or UV, or even an emission line.
At the left of the NED page are images. Clicking on an image zooms in.
M31 is a spiral galaxy in the Local Group.
Here is its spectrogram showing the optical wavelength band:
click to view the image:
There are 2 dips below 4000 Angstroms. Those are the 2 absorption lines from calcium ions in the line of sight to M31.
The blue shift in those absorption lines is the justification of the M31 relative velocity of 401 km/s toward Earth. Atoms in the line of sight cannot be used to measure a large galaxy. This velocity is a mistake.
Here is its spectrogram in the ultraviolet wavelength band:
click to view the image:
There is a strong emission line around 1215 Angstroms. That LAE wavelength will be described below.
M33 is a spiral galaxy in the Local Group. It is also known as the Triangulum Galaxy, for its constellation.
Here is its spectrogram in the optical wavelength band:
The optical spectrogram in NED for M33 has a slightly different span of wavelengths than for M31.
Both galaxies show the signature of synchrotron radiation with the range of wavelengths from ultraviolet to infrared having a similar intensity. Each dip is from atoms in the line of sight absorbing their characteristic wavelengths.
M33 has several absorption lines from atoms in the line of sight. They are the justification of the M33 relative velocity of 179 km/s toward Earth. Atoms in the line of sight cannot be used to measure a galaxy's velocity. This value is a mistake.
Here is the M33 spectrogram in the ultraviolet wavelength band:
Just like with M31, there is a strong emission line near 1216 Angstroms. M33 is LAE.
7.6 Lyman Alpha Emitter Galaxy
A Lyman-alpha emitter (LAE) is a type of distant galaxy that emits Lyman-alpha radiation from neutral hydrogen.
Most known LAEs are extremely distant, and because of the finite travel time of light they provide glimpses into the history of the universe. They are thought to be the progenitors of most modern Milky Way type galaxies.
The baryonic acoustic oscillation signal should be evident in the power spectrum of Lyman-alpha emitters at high redshift. Baryonic acoustic oscillations are imprints of sound waves on scales where radiation pressure stabilized the density perturbations against gravitational collapse in the early universe. The three-dimensional distribution of the characteristically homogeneous Lyman-alpha galaxy population will allow a robust probe of cosmology.
They are a good tool because the Lyman-alpha bias, the propensity for galaxies to form in the highest overdensity of the underlying dark matter distribution, can be modeled and accounted for. Lyman-alpha emitters are over dense in clusters. [ Reference:
This description reveals much confusion. First, the Lyman-alpha emission line occurs a proton captures an electron, and the electron drops to the hydrogen ground state.
M31 and M33 have this line and neither has a high redshift for their accepted velocity.
References to "baryonic acoustic oscillation" are meaningless. Attempts to model "dark matter distribution" are meaningless. There is no dark matter. That mistake is covered in the TFR part of section NED Distances.
This Lyman-alpha emission occurs from an event in the line of sight to a galaxy. That event is a proton capturing an electron. This event cannot be related to the galaxy. Trying to link this event to the age of a galaxy is unjustified and ridiculous.
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;ast update: 01/05/2022