Community hub
Recent from talks
Knowledge base stats:
Talk channels stats:
Members stats:
Luminous infrared galaxy
Luminous infrared galaxies or LIRGs are galaxies with luminosities above 1011 L☉. They are also referred to as submillimeter galaxies (SMGs) through their normal method of detection. LIRGs are more abundant than starburst galaxies, Seyfert galaxies and quasi-stellar objects at comparable luminosity.[citation needed] Infrared galaxies emit more energy in the infrared than at all other wavelengths combined. A LIRG's luminosity is 100 billion times that of the Sun.
Galaxies with luminosities above 1012 L☉ are known as ultraluminous infrared galaxies (ULIRGs). Galaxies exceeding 1013 L☉ are characterised as hyper-luminous infrared galaxies (HyLIRGs). Those exceeding 1014 L☉ are extremely luminous infrared galaxies (ELIRGs). Many of the LIRGs and ULIRGs are showing interactions and disruptions. Many of these types of galaxies spawn about 100 new stars a year as compared to the Milky Way which spawns one a year; this helps create the high level of luminosity.
Infrared galaxies originally appeared to be single, gas-rich spirals whose infrared luminosity is created largely by the formation of stars within them. These types of galaxies were discovered in 1983 with IRAS. A LIRG's excess infrared luminosity may also come from the presence of an active galactic nucleus (AGN) residing at the center. It was ultimately found that many LIRGs are actually mergers of two or more gas-rich spiral galaxies, with the fraction of mergers to non-mergers increasing with increasing infrared luminosity.
These galaxies emit more energy in the infrared portion of the spectrum, not visible to the naked eye. The energy given off by LIRGs is comparable to that of a quasar (a type of AGN), which formerly was known as the most energetic object in the universe.
LIRGs are brighter in the infrared than in the optical spectrum because the visible light is absorbed by the high amounts of gas and dust, and the dust re-emits thermal energy in the infrared spectrum.
LIRGs are known to exist in denser parts of the universe than non-LIRGs.
LIRGs are also capable of becoming Ultra Luminous Infrared Galaxies (ULIRGs) but not all LIRGs become ULIRGs, thus there is no clear time scale at which this happens.Studies have shown that ULIRGs are more likely to contain an AGN than LIRGs
According to one study a ULIRG is just part of an evolutionary galaxy merger scenario. In essence, two or more spiral galaxies, galaxies that consist of a flat, rotating disk containing stars, gas and dust and a central concentration of stars known as the bulge, merge to form an early stage merger. An early stage merger in this case can also be identified as a LIRG. After that, it becomes a late stage merger, which is a ULIRG. It then becomes a quasar and in the final stage of the evolution it becomes an elliptical galaxy. This can be evidenced by the fact that stars are much older in elliptical galaxies than those found in the earlier stages of the evolution.
Hub AI
Luminous infrared galaxy AI simulator
(@Luminous infrared galaxy_simulator)
Luminous infrared galaxy
Luminous infrared galaxies or LIRGs are galaxies with luminosities above 1011 L☉. They are also referred to as submillimeter galaxies (SMGs) through their normal method of detection. LIRGs are more abundant than starburst galaxies, Seyfert galaxies and quasi-stellar objects at comparable luminosity.[citation needed] Infrared galaxies emit more energy in the infrared than at all other wavelengths combined. A LIRG's luminosity is 100 billion times that of the Sun.
Galaxies with luminosities above 1012 L☉ are known as ultraluminous infrared galaxies (ULIRGs). Galaxies exceeding 1013 L☉ are characterised as hyper-luminous infrared galaxies (HyLIRGs). Those exceeding 1014 L☉ are extremely luminous infrared galaxies (ELIRGs). Many of the LIRGs and ULIRGs are showing interactions and disruptions. Many of these types of galaxies spawn about 100 new stars a year as compared to the Milky Way which spawns one a year; this helps create the high level of luminosity.
Infrared galaxies originally appeared to be single, gas-rich spirals whose infrared luminosity is created largely by the formation of stars within them. These types of galaxies were discovered in 1983 with IRAS. A LIRG's excess infrared luminosity may also come from the presence of an active galactic nucleus (AGN) residing at the center. It was ultimately found that many LIRGs are actually mergers of two or more gas-rich spiral galaxies, with the fraction of mergers to non-mergers increasing with increasing infrared luminosity.
These galaxies emit more energy in the infrared portion of the spectrum, not visible to the naked eye. The energy given off by LIRGs is comparable to that of a quasar (a type of AGN), which formerly was known as the most energetic object in the universe.
LIRGs are brighter in the infrared than in the optical spectrum because the visible light is absorbed by the high amounts of gas and dust, and the dust re-emits thermal energy in the infrared spectrum.
LIRGs are known to exist in denser parts of the universe than non-LIRGs.
LIRGs are also capable of becoming Ultra Luminous Infrared Galaxies (ULIRGs) but not all LIRGs become ULIRGs, thus there is no clear time scale at which this happens.Studies have shown that ULIRGs are more likely to contain an AGN than LIRGs
According to one study a ULIRG is just part of an evolutionary galaxy merger scenario. In essence, two or more spiral galaxies, galaxies that consist of a flat, rotating disk containing stars, gas and dust and a central concentration of stars known as the bulge, merge to form an early stage merger. An early stage merger in this case can also be identified as a LIRG. After that, it becomes a late stage merger, which is a ULIRG. It then becomes a quasar and in the final stage of the evolution it becomes an elliptical galaxy. This can be evidenced by the fact that stars are much older in elliptical galaxies than those found in the earlier stages of the evolution.