NGC 3226
Encyclopedia
NGC 3226 is a dwarf elliptical galaxy
that is interacting with the spiral galaxy
NGC 3227
. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies
. Both galaxies may be found in the constellation
Leo
.
(LINER), a type of region that is characterized by spectral line
emission from weakly ion
ized atoms. In general, the energy source for LINER emission has been a subject of debate among astronomers. Some astronomers have asserted that LINERs are powered by star formation region
s, while other have asserted that LINERs are powered by active galactic nuclei (AGN) which contain supermassive black hole
s.
and X-ray
emission that appears to be synchrotron emission, which is generated when electron
s moving at high speeds oscillate within magnetic field
s. Such synchrotron emission is expected from the environment around a supermassive black hole
. The X-ray
emission may also be variable, which is also expected in the environment of a supermassive black hole.
within NGC 3226. However, millimeter observations of NGC 3226 failed to detect any molecular gas within the galaxy. These results not only demonstrate that NGC 3226 contains little molecular gas but also demonstrate that the galaxy has acquired no gas from NGC 3227.
Dwarf elliptical galaxy
Dwarf elliptical galaxies, or dEs, are elliptical galaxies that are much smaller than others. They are classified as dE, and are quite common in galaxy groups and clusters, and are usually companions to other galaxies.- Examples :...
that is interacting with the spiral galaxy
Spiral galaxy
A spiral galaxy is a certain kind of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, forms part of the Hubble sequence. Spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as...
NGC 3227
NGC 3227
NGC 3227 is a spiral galaxy that is interacting with the dwarf elliptical galaxy NGC 3226. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies...
. The two galaxies are one of several examples of a spiral with a dwarf elliptical companion that are listed in the Atlas of Peculiar Galaxies
Atlas of Peculiar Galaxies
The Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology....
. Both galaxies may be found in the constellation
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
Leo
Leo (constellation)
Leo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is . Leo lies between dim Cancer to the west and Virgo to the east.-Stars:...
.
Nucleus
NGC 3226 contains a low-ionization nuclear emission-line regionLow-ionization nuclear emission-line region
A low-ionization nuclear emission-line region is a type of galactic nucleus that is defined by its spectral line emission. The spectra typically include line emission from weakly ionized or neutral atoms, such as O, O+, N+, and S+. Conversely, the spectral line emission from strongly ionized...
(LINER), a type of region that is characterized by spectral line
Spectral line
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from a deficiency or excess of photons in a narrow frequency range, compared with the nearby frequencies.- Types of line spectra :...
emission from weakly ion
Ion
An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
ized atoms. In general, the energy source for LINER emission has been a subject of debate among astronomers. Some astronomers have asserted that LINERs are powered by star formation region
Star formation
Star formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
s, while other have asserted that LINERs are powered by active galactic nuclei (AGN) which contain supermassive black hole
Supermassive black hole
A supermassive black hole is the largest type of black hole in a galaxy, in the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.Supermassive black holes have...
s.
AGN
The nucleus of NGC 3226 appears to contain an AGN. The nucleus is a strong source of both radioRadio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
and X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
emission that appears to be synchrotron emission, which is generated when electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s moving at high speeds oscillate within magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
s. Such synchrotron emission is expected from the environment around a supermassive black hole
Supermassive black hole
A supermassive black hole is the largest type of black hole in a galaxy, in the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.Supermassive black holes have...
. The X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...
emission may also be variable, which is also expected in the environment of a supermassive black hole.
Interstellar medium
It is possible that NGC 3226 may be acquiring gas from NGC 3227 during the interaction process, which would enhance star formationStar formation
Star formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
within NGC 3226. However, millimeter observations of NGC 3226 failed to detect any molecular gas within the galaxy. These results not only demonstrate that NGC 3226 contains little molecular gas but also demonstrate that the galaxy has acquired no gas from NGC 3227.