NGC 1316
Encyclopedia
NGC 1316 is a lenticular galaxy
about 70 million light-year
s away in the constellation
Fornax
. NGC 1316 is a radio galaxy
. It is the fourth-brightest radio source in the sky (as seen at 1400 MHz).
with some unusual dust lanes embedded within a much larger envelope of stars. The outer envelope contained many ripples, loops, and arcs. He also identified the presence of a compact disk of gas near the center that appeared inclined relative to the stars and that appeared to rotate faster than the stars. Based on these results, Schweizer suggested that NGC 1316 was built up through the merger of several smaller galaxies. These merger events may have fueled the central supermassive black hole
with gas, causing the galaxy to become a radio galaxy
. He also states that NGC 1316 is comparable to the giant elliptical galaxies found in the centers of other clusters of galaxies. Using spectroscopy of its brightest globular cluster
s, the merger is estimated to have occurred ~3 Gyr ago.
, a cluster of galaxies in the constellation Fornax
. However, in contrast to Messier 87
, which is a similar elliptical galaxy
that is located in the center of the Virgo Cluster
, NGC 1316 is located at the edge of the Fornax Cluster.
NGC 1316 appears to be interacting with NGC 1317, a small spiral galaxy to the north. However, that small spiral galaxy does not appear to be sufficiently large to cause the distortions seen in the structure of this galaxy.
NGC 1316 was host to two well-observed type Ia supernova 1980N(Ia) and 1981D(Ia).
(SBF) in 2003 and planetary nebula luminosity function
(PNLF) in 2006. Being a lenticular galaxy, it is not suitable to apply the cepheid variable
method. Using SBF, a distance estimate of 20.0 ± 1.6 Mpc
was computed. Using PNLF, 45 planetary nebula
candidates were located and a distance estimate of 17.9 Mpc was computed. Averaged together, these two distance measurements give a combined distance estimate of 62.0 ± 2.9 Mly (19.0 ± 0.9 Mpc).
Lenticular galaxy
A lenticular galaxy is a type of galaxy which is intermediate between an elliptical galaxy and a spiral galaxy in galaxy morphological classification schemes. Lenticular galaxies are disk galaxies which have used up or lost most of their interstellar matter and therefore have very little ongoing...
about 70 million light-year
Light-year
A light-year, also light year or lightyear is a unit of length, equal to just under 10 trillion kilometres...
s away 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....
Fornax
Fornax
Fornax is a constellation in the southern sky. Its name is Latin for furnace. It was created in the 18th century and is now one of the 88 modern constellations.-History:Fornax was formed by Nicolas Louis de Lacaille in 1756...
. NGC 1316 is a radio galaxy
Radio galaxy
Radio galaxies and their relatives, radio-loud quasars and blazars, are types of active galaxy that are very luminous at radio wavelengths, with luminosities up to 1039 W between 10 MHz and 100 GHz. The radio emission is due to the synchrotron process...
. It is the fourth-brightest radio source in the sky (as seen at 1400 MHz).
Structure and formation
François Schweizer studied NGC 1316 extensively in the late 1970s. He found that the galaxy appeared to look like a small elliptical galaxyElliptical galaxy
An elliptical galaxy is a galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile. They range in shape from nearly spherical to highly flat and in size from hundreds of millions to over one trillion stars...
with some unusual dust lanes embedded within a much larger envelope of stars. The outer envelope contained many ripples, loops, and arcs. He also identified the presence of a compact disk of gas near the center that appeared inclined relative to the stars and that appeared to rotate faster than the stars. Based on these results, Schweizer suggested that NGC 1316 was built up through the merger of several smaller galaxies. These merger events may have fueled the central supermassive black hole
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
with gas, causing the galaxy to become a radio galaxy
Radio galaxy
Radio galaxies and their relatives, radio-loud quasars and blazars, are types of active galaxy that are very luminous at radio wavelengths, with luminosities up to 1039 W between 10 MHz and 100 GHz. The radio emission is due to the synchrotron process...
. He also states that NGC 1316 is comparable to the giant elliptical galaxies found in the centers of other clusters of galaxies. Using spectroscopy of its brightest globular cluster
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
s, the merger is estimated to have occurred ~3 Gyr ago.
Companions and environment
NGC 1316 is located within the Fornax ClusterFornax Cluster
At a distance of approximately 62.0 Mly , the Fornax Cluster is the second richest cluster of galaxies within 100 million light-years, although it is much smaller than the Virgo Cluster. It lies primarily in the constellation Fornax, and may be associated with the nearby Eridanus Group...
, a cluster of galaxies in the constellation Fornax
Fornax
Fornax is a constellation in the southern sky. Its name is Latin for furnace. It was created in the 18th century and is now one of the 88 modern constellations.-History:Fornax was formed by Nicolas Louis de Lacaille in 1756...
. However, in contrast to Messier 87
Messier 87
Messier 87 is a supergiant elliptical galaxy. It was discovered in 1781 by the French astronomer Charles Messier, who cataloged it as a nebulous feature. The second brightest galaxy within the northern Virgo Cluster, it is located about 16.4 million parsecs from Earth...
, which is a similar elliptical galaxy
Elliptical galaxy
An elliptical galaxy is a galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile. They range in shape from nearly spherical to highly flat and in size from hundreds of millions to over one trillion stars...
that is located in the center of the Virgo Cluster
Virgo Cluster
The Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly away in the constellation Virgo. Comprising approximately 1300 member galaxies, the cluster forms the heart of the larger Local Supercluster, of which the Local Group is an outlying member...
, NGC 1316 is located at the edge of the Fornax Cluster.
NGC 1316 appears to be interacting with NGC 1317, a small spiral galaxy to the north. However, that small spiral galaxy does not appear to be sufficiently large to cause the distortions seen in the structure of this galaxy.
NGC 1316 was host to two well-observed type Ia supernova 1980N(Ia) and 1981D(Ia).
Distance estimates
At least two methods have been used to estimate the distance to NGC 1316: surface brightness fluctuationSurface brightness fluctuation
Surface brightness fluctuation is a secondary distance indicator used to estimate distances to galaxies. The technique uses the fact that galaxies are made up of a finite number of stars. The number of stars in any small patch of the galaxy will vary from point to point, creating a noise-like...
(SBF) in 2003 and planetary nebula luminosity function
Planetary nebula luminosity function
Planetary nebula luminosity function is a secondary distance indicator used in astronomy. It makes use of the [O III] λ5007 forbidden line found in all planetary nebula which are members of the old stellar populations ....
(PNLF) in 2006. Being a lenticular galaxy, it is not suitable to apply the cepheid variable
Cepheid variable
A Cepheid is a member of a class of very luminous variable stars. The strong direct relationship between a Cepheid variable's luminosity and pulsation period, secures for Cepheids their status as important standard candles for establishing the Galactic and extragalactic distance scales.Cepheid...
method. Using SBF, a distance estimate of 20.0 ± 1.6 Mpc
Parsec
The parsec is a unit of length used in astronomy. It is about 3.26 light-years, or just under 31 trillion kilometres ....
was computed. Using PNLF, 45 planetary nebula
Planetary nebula
A planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life...
candidates were located and a distance estimate of 17.9 Mpc was computed. Averaged together, these two distance measurements give a combined distance estimate of 62.0 ± 2.9 Mly (19.0 ± 0.9 Mpc).
See also
- Centaurus ACentaurus ACentaurus A is a prominent galaxy in the constellation of Centaurus. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type and distance...
- an elliptical/peculiar galaxy that is a strong source of radioRadioRadio 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...
emission - Messier 87Messier 87Messier 87 is a supergiant elliptical galaxy. It was discovered in 1781 by the French astronomer Charles Messier, who cataloged it as a nebulous feature. The second brightest galaxy within the northern Virgo Cluster, it is located about 16.4 million parsecs from Earth...
- an elliptical galaxy at the center of the Virgo ClusterVirgo ClusterThe Virgo Cluster is a cluster of galaxies whose center is 53.8 ± 0.3 Mly away in the constellation Virgo. Comprising approximately 1300 member galaxies, the cluster forms the heart of the larger Local Supercluster, of which the Local Group is an outlying member...
that contains relativistic jetRelativistic jetRelativistic jets are extremely powerful jets of plasma which emerge from presumed massive objects at the centers of some active galaxies, notably radio galaxies and quasars. Their lengths can reach several thousand or even hundreds of thousands of light years...
s originating from a supermassive central black holeBlack holeA black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that... - NGC 1097NGC 1097NGC 1097 is a barred spiral galaxy about 45 million light-years away in the constellation Fornax. As of 2006, three supernovae have been observed in NGC 1097....
- a spiral galaxy with relativistic jetRelativistic jetRelativistic jets are extremely powerful jets of plasma which emerge from presumed massive objects at the centers of some active galaxies, notably radio galaxies and quasars. Their lengths can reach several thousand or even hundreds of thousands of light years...
s visible in optical light