Luminous infrared galaxy
Luminous infrared galaxies or LIRGs are
Galaxies with luminosities above 1012 L☉ are 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.
Discovery and characteristics
Infrared galaxies appear to be single, gas-rich spirals whose infrared luminosity is created largely by the formation of stars within them.[1] These types of galaxies were discovered in 1983 with IRAS.[2] A LIRG's excess infrared luminosity may also come from the presence of an active galactic nucleus (AGN) residing at the center.[3][4]
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.[5]
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.
ULIRG
LIRGs are also capable of becoming Ultra Luminous Infrared Galaxys (ULIRGs) but there is no perfect timetable because not all LIRGs turn into ULIRGs,
According to one study a ULIRG is just part of an evolutionary
HyLIRG
Hyper luminous Infrared Galaxies (HyLIRG), also referred to as HiLIRGs and HLIRGs, are considered to be some of the most luminous persistent objects in the Universe, exhibiting extremely high star formation rates, and most of which are known to harbour Active Galactic Nuclei (AGN). They are defined as galaxies with luminosities above 1013 L⊙,[8] as distinct from the less luminous population of ULIRGs (L = 1012 – 1013 L⊙). HLIRGs were first identified through follow-up observations of the IRAS mission.[9][10]
IRAS F10214+4724, a HyLIRG being
The majority (~80%) of the mid-infrared spectrum of these objects is found to be dominated by AGN emission. However, the starburst (SB) activity is known to be significant in all known sources with a mean SB contribution of ~30%.[13] Star formation rates in HLIRGs have been shown to reach ~ 3×102 – 3×103 M⊙ yr−1.[14]
ELIRG
The Extremely Luminous Infrared Galaxy
Light from the
There are three reasons the black holes in the ELIRGs could be massive. First, the embryonic black holes might be bigger than thought possible. Second, the
Twenty new ELIRGs, including the most luminous galaxy found to date, have been discovered. These galaxies were not found earlier because of their distance, and because dust converts their visible light into infrared light.[15][16] One has been observed to have three star-forming areas.[17]
Observations
IRAS
The
GOALS
The Great Observatories All-sky LIRG Survey (GOALS) is a multi-wavelength study of luminous infrared galaxies,
List
Some examples of extremely notable LIRGs, ULIRGs, HLIRGs, ELIRGs
Galaxy | Type | Luminosity | Constellation | RA | DEC | Notes | |
---|---|---|---|---|---|---|---|
WISE J224607.57-052635.0
|
ELIRG | Aquarius | 22h 46m 07.57s | −05° 26′ 35.0″ | Discovered in 2015, the most luminous galaxy known, as of 2015 | [20] | |
Arp 220 | ULIRG | Serpens | the closest ULIRG, it is in the process of merging two galaxies. | ||||
Markarian 231 | ULIRG | Ursa Major | galaxy that underwent a merger and contains a quasar | ||||
Markarian 273 | ULIRG | Ursa Major | a well studied nearby ultraluminous infrared galaxy merger. | ||||
FSC15307+3253
|
ULIRG | Corona Borealis | |||||
Arp 299 | LIRG | Ursa Major | an object where a pair of galaxies are merging | ||||
II Zw 96 | LIRG | Delphinus | an object where a pair of galaxies are merging | ||||
Messier 77 | LIRG | Cetus | Seyfert galaxy | ||||
NGC 1275 | LIRG | Perseus | radio galaxy, central galaxy of Perseus Cluster | ||||
NGC 1365 | LIRG | Fornax | barred spiral galaxy | ||||
NGC 1614 | LIRG | Eridanus | galaxy undergoing minor merger | ||||
NGC 2146 | LIRG | Camelopardalis | galaxy undergoing minor merger | ||||
NGC 2623 | LIRG | Cancer | galaxy merger | ||||
NGC 3256 | LIRG | Vela | most luminous galaxy in infrared within z<0,01 | ||||
NGC 6090 | LIRG | Draco | galaxy merger | ||||
NGC 6240 | LIRG | Ophiuchus | a well studied nearby infrared galaxy | ||||
NGC 7469 | LIRG | Pegasus | active galaxy with starburst nuclear ring | ||||
NGC 7674 | LIRG | Pegasus | |||||
UGC 5101 | LIRG | Ursa Major | galaxy merger |
Image gallery
References
- .
- ISSN 0004-637X.
- Bibcode:2009ASPC..408....3S.)
{{cite journal}}
: CS1 maint: multiple names: authors list (link - S2CID 121448953.
- ^ a b "The Curious History of Luminous Infrared Galaxies". Retrieved 24 October 2013.
- ^ "When galaxies collide". spacetelescope.org. ESA. 2 January 2017. potw1701a. Retrieved 10 January 2017.
- ^ "Star-formation, AGN and Ultra-luminous infrared galaxies". Retrieved 12 November 2013.
- S2CID 16044339.
- S2CID 4333900.
- hdl:1887/6544.
- S2CID 50462976.
- S2CID 15781541.
- S2CID 54212380.
- .
- ^ Karen Northon (21 May 2015). "NASA's WISE Spacecraft Discovers Most Luminous Galaxy in Universe". nasa.gov. NASA Jet Propulsion Laboratory. 15-095. Retrieved 2015-05-25.
- S2CID 39280020.
- ^ Deborah Byrd (29 August 2018). "Astronomers map a starburst galaxy". earthsky.org. EarthSky Communications. Retrieved 2018-08-30.
- S2CID 6162900.
- ^ "GOALS". Great Observatories All-sky LIRG Survey. Caltech. Retrieved 24 October 2013.
- Science Daily. 21 May 2015.
- ^ Staff (21 May 2015). "WISE spacecraft discovers most luminous galaxy in universe". PhysOrg. Retrieved 22 May 2015.
- ^ Staff (21 May 2015). "PIA19339: Dusty 'Sunrise' at Core of Galaxy (Artist's Concept)". NASA. Retrieved 21 May 2015.
- ^ "A very bright contortionist". ESA/Hubble Picture of the Week. ESA. 10 June 2013. potw1323a. Retrieved 14 June 2013.
- ^ "A tale of galactic collisions". ESA/Hubble Picture of the Week. ESA. 6 May 2013. potw1318a. Retrieved 6 May 2013.
- ^ "A galaxy colourfully on the wane ain't dead yet". ESA/Hubble Picture of the Week. ESA. 5 November 2012. potw1245a. Retrieved 12 November 2012.
- ^ "Starbursts versus Monsters". ESA / HUBBLE. ESA. 17 February 2014. potw1407a. Retrieved 12 March 2014.
External links
- Nearby Extreme Galaxies Linked To Humble Roots (SpaceDaily) Jun 07, 2006
- How To Bake A Galaxy (SpaceDaily) Jun 19, 2006
- The Great Observatory All-sky LIRG Survey