luminous infrared galaxy

Infrared galaxies appear to be single, gas-rich spirals whose infrared luminosity is created largely by the formation of stars within them.{{cite journal|title=Luminous Infrared Galaxies|doi=10.1146/annurev.astro.34.1.749|journal=Annual Review of Astronomy and Astrophysics|volume=34|date=September 1996|pages=749–792|bibcode=1996ARA&A..34..749S |author=D. B. Sanders |author2=I. F. Mirabel}} These types of galaxies were discovered in 1983 with IRAS.{{Cite journal|last1=Soifer|first1=B. T.|last2=Rowan-Robinson|first2=M.|last3=Houck|first3=J. R.|last4=de Jong|first4=T.|last5=Neugebauer|first5=G.|last6=Aumann|first6=H. H.|last7=Beichman|first7=C. A.|last8=Boggess|first8=N.|author-link8=Nancy Boggess|last9=Clegg|first9=P. E.|date=March 1984|title=Infrared galaxies in the IRAS minisurvey|bibcode=1984ApJ...278L..71S|journal=The Astrophysical Journal|language=en|volume=278|pages=L71|doi=10.1086/184226|issn=0004-637X|url=https://authors.library.caltech.edu/74853/1/1984ApJ___278L__71S.pdf}} A LIRG's excess infrared luminosity may also come from the presence of an active galactic nucleus (AGN) residing at the center.{{Cite journal|last1=B.|first1=Sanders, D.|last2=S.|first2=Kartaltepe, J.|last3=J.|first3=Kewley, L.|last4=Vivian|first4=U|last5=T.|first5=Yuan|last6=S.|first6=Evans, A.|last7=L.|first7=Armus|last8=M.|first8=Mazzarella, J.|date=October 2009|title=Luminous Infrared Galaxies and the Starburst-AGN Connection|journal=The Starburst-Agn Connection|bibcode=2009ASPC..408....3S|language=en|volume=408|pages=3}}{{Cite journal|last1=de Grijp|first1=M. H. K.|last2=Miley|first2=G. K.|last3=Lub|first3=J.|last4=de Jong|first4=T.|date=March 1985|title=Infrared Seyferts: a new population of active galaxies?|bibcode=1985Natur.314..240D|journal=Nature|language=en|volume=314|issue=6008|pages=240–242|doi=10.1038/314240a0|s2cid=121448953|issn=0028-0836}}

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.{{cite news|title=The Curious History of Luminous Infrared Galaxies|url=http://candels-collaboration.blogspot.com/2012/07/luminous-infrared-galaxies.html|access-date=24 October 2013}}

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.

File:When galaxies collide IRAS 14348-1447.jpg is an ultraluminous infrared galaxy, located over a billion light-years away.{{cite web|title=When galaxies collide|url=https://www.spacetelescope.org/images/potw1701a/|website=spacetelescope.org|publisher=ESA |access-date=10 January 2017 |id=potw1701a |date=2 January 2017}}]]

LIRGs are also capable of becoming Ultra Luminous Infrared Galaxys (ULIRGs) but there is no perfect timetable because not all LIRGs turn into ULIRGs. Studies have shown that ULIRGs are more likely to contain an AGN than LIRGs{{cite news|title=Star-formation, AGN and Ultra-luminous infrared galaxies|url=http://blog.galaxyzoo.org/2012/02/17/star-formation-agn-and-ultra-luminous-infrared-galaxies/|access-date=12 November 2013}}

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.

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_⊙,{{Cite journal|last1=Serjeant|first1=Stephen|last2=Farrah|first2=Duncan|last3=Geach|first3=James|last4=Takagi|first4=Toshinobu|last5=Verma|first5=Aprajita|last6=Kaviani|first6=Ali|last7=Fox|first7=Matt|date=2003-12-21|title=The K-band Hubble diagram of submillimetre galaxies and hyperluminous galaxies|journal=Monthly Notices of the Royal Astronomical Society|language=en|volume=346|issue=4|pages=L51–L56|doi=10.1111/j.1365-2966.2003.07305.x|doi-access=free |issn=0035-8711|arxiv=astro-ph/0310661|bibcode=2003MNRAS.346L..51S|s2cid=16044339}} 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.{{Cite journal|last1=Rowan-Robinson|first1=M.|last2=Broadhurst|first2=T.|last3=Lawrence|first3=A.|last4=McMahon|first4=R. G.|last5=Lonsdale|first5=C. J.|last6=Oliver|first6=S. J.|last7=Taylor|first7=A. N.|last8=Hacking|first8=P. B.|last9=Conrow|first9=T.|title=A high-redshift IRAS galaxy with huge luminosity—hidden quasar or protogalaxy?|journal=Nature|volume=351|issue=6329|pages=719–721|doi=10.1038/351719a0|bibcode=1991Natur.351..719R|year=1991|s2cid=4333900}}{{Cite journal|last1=Kleinmann|first1=S. G.|last2=Hamilton|first2=Donald|last3=Keel|first3=W. C.|last4=Wynn-Williams|first4=C. G.|last5=Eales|first5=S. A.|last6=Becklin|first6=E. E.|last7=Kuntz|first7=K. D.|title=The properties and environment of the giant, infrared-luminous galaxy IRAS 09104 + 4109|journal=The Astrophysical Journal|volume=328|pages=161|doi=10.1086/166276|bibcode=1988ApJ...328..161K|year=1988|hdl=1887/6544|hdl-access=free}}

IRAS F10214+4724, a HyLIRG being gravitationally lensed by a foreground elliptical galaxy,{{Cite journal|last1=Broadhurst|first1=Tom|last2=Lehár|first2=Joseph|title=A Gravitational Lens Solution for the IRAS Galaxy FSC 10214+4724|journal=The Astrophysical Journal|volume=450|issue=2|pages=L41–L44|doi=10.1086/316774|arxiv=astro-ph/9505013|bibcode=1995ApJ...450L..41B|year=1995|s2cid=50462976}} was considered to be one of the most luminous objects in the Universe having an intrinsic luminosity of ~ 2 × 10¹³ L_⊙.{{Cite journal|last1=Eisenhardt|first1=Peter R.|last2=Armus|first2=Lee|last3=Hogg|first3=David W.|last4=Soifer|first4=B. T.|last5=Neugebauer|first5=G.|last6=Werner|first6=Michael W.|date=1996-04-01|title=Hubble Space Telescope Observations of the Luminous IRAS Source FSC 10214+4724: A Gravitationally Lensed Infrared Quasar|journal=The Astrophysical Journal|volume=461|pages=72|doi=10.1086/177038|issn=0004-637X|arxiv=astro-ph/9510093|bibcode=1996ApJ...461...72E|s2cid=15781541}} It is believed that the bolometric luminosity of this HLIRG is likely amplified by a factor of ~30 as a result of the gravitational lensing.

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%.{{Cite journal|last1=Ruiz|first1=A.|last2=Risaliti|first2=G.|last3=Nardini|first3=E.|last4=Panessa|first4=F.|last5=Carrera|first5=F. J.|date=January 2013|title=Analysis of Spitzer-IRS spectra of hyperluminous infrared galaxies|journal=Astronomy & Astrophysics|volume=549|pages=A125|doi=10.1051/0004-6361/201015257|issn=0004-6361|arxiv=1210.3915|bibcode=2013A&A...549A.125R|s2cid=54212380}} Star formation rates in HLIRGs have been shown to reach ~ 3×10² – 3×10³ M_⊙ yr⁻¹.{{Cite journal|last=Rowan-Robinson|first=M.|title=Hyperluminous infrared galaxies|journal=Monthly Notices of the Royal Astronomical Society|volume=316|issue=4|pages=885–900|doi=10.1046/j.1365-8711.2000.03588.x|arxiv=astro-ph/9912286|bibcode=2000MNRAS.316..885R|year=2000|doi-access=free }}

The Extremely Luminous Infrared Galaxy WISE J224607.57-052635.0, with a luminosity of 300 trillion suns was discovered by NASA's Wide-field Infrared Survey Explorer (WISE), and as of May 2015 is the most luminous galaxy found. The galaxy belongs to a new class of objects discovered by WISE, extremely luminous infrared galaxies, or ELIRGs.

Light from the WISE J224607.57-052635.0 galaxy has traveled 12.5 billion years. The black hole at its center was billions of times the mass of the Sun when the universe was a tenth (1.3 billion years) of its present age of 13.8 billion years.

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 Eddington limit was exceeded. When a black hole feeds, gas falls in and heats, emitting light. The pressure of the emitted light forces the gas outward, creating a limit to how fast the black hole can continuously absorb matter. If a black hole broke this limit, it could theoretically increase in size at a fast rate. Black holes have previously been observed breaking this limit; the black hole in the study would have had to repeatedly break the limit to grow this large. Third, the black holes might just be bending this limit, absorbing gas faster than thought possible, if the black hole is not spinning fast. If a black hole spins slowly, it will not repel its gas absorption as much. A slow-spinning black hole can absorb more matter than a fast-spinning black hole. The massive black holes in ELIRGs could be absorbing matter for a longer time.

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.{{Cite web |title= NASA's WISE Spacecraft Discovers Most Luminous Galaxy in Universe |url= http://www.nasa.gov/press-release/nasas-wise-spacecraft-discovers-most-luminous-galaxy-in-universe |access-date= 2015-05-25 |website= nasa.gov |id= 15-095 |author= Karen Northon |publisher= NASA Jet Propulsion Laboratory |date= 21 May 2015 }}{{Cite journal|title = The Most Luminous Galaxies Discovered by WISE|journal= The Astrophysical Journal|volume= 805|issue= 2|pages= 90|arxiv= 1410.1751|date = 2014-10-07|first1 = Chao-Wei|last1 = Tsai|first2 = Peter|last2 = Eisenhardt|first3 = Jingwen|last3 = Wu|first4 = Daniel|last4 = Stern|first5 = Roberto|last5 = Assef|first6 = Andrew|last6 = Blain|first7 = Carrie|last7 = Bridge|first8 = Dominic|last8 = Benford|first9 = Roc|last9 = Cutri|doi= 10.1088/0004-637X/805/2/90|bibcode = 2015ApJ...805...90T |s2cid= 39280020}} One has been observed to have three star-forming areas.{{Cite web|url=http://earthsky.org/space/starburst-galaxy-cosmos-aztec-1-unstoppable-monster|title=Astronomers map a starburst galaxy|website=earthsky.org|publisher=EarthSky Communications|author=Deborah Byrd|date=29 August 2018|language=en-US|access-date=2018-08-30}}

The Infrared Astronomical Satellite (IRAS) was the first all-sky survey which used far-infrared wavelengths, in 1983. In that survey, tens of thousands of galaxies were detected, many of which would not have been recorded in previous surveys. It is now clear that the reason the number of detections has risen is that the majority of LIRGs in the universe emitted the bulk of their energy in the far infrared. Using the IRAS, scientists were able to determine the luminosity of the galactic objects discovered. The telescope was a joint project of the United States (NASA), Netherlands (NIVR), and the United Kingdom (SERC). Over 250,000 infrared sources were observed during this 10-month mission.

The Great Observatories All-sky LIRG Survey (GOALS) is a multi-wavelength study of luminous infrared galaxies,{{Cite journal|title=Mid-Infrared Properties of Nearby Luminous Infrared Galaxies I: Spitzer IRS Spectra for the GOALS sample|journal=The Astrophysical Journal Supplement Series|volume=206|issue=1|pages=1|arxiv=1302.4477|last1= Stierwalt|first1=S.|last2= Armus|first2=L.|last3= Surace|first3=J. A.|last4= Inami|first4=H.|last5= Petric|first5=A. O.|last6= Diaz-Santos|first6=T.|last7= Haan|first7=S.|last8= Charmandaris|first8=V.|last9= Howell|first9=J.|last10= Kim|first10=D. C.|last11= Marshall|first11=J.|last12= Mazzarella|first12=J. M.|last13= Spoon|first13=H. W. W.|last14= Veilleux|first14=S.|last15= Evans|first15=A.|last16= Sanders|first16=D. B.|last17= Appleton|first17=P.|last18= Bothun|first18=G.|last19= Bridge|first19=C. R.|last20= Chan|first20=B.|last21= Frayer|first21=D.|last22= Iwasawa|first22=K.|last23= Kewley|first23=L. J.|last24= Lord|first24=S.|last25= Madore|first25=B. F.|last26= Melbourne|first26=J. E.|last27= Murphy|first27=E. J.|last28= Rich|first28=J. A.|last29= Schulz|first29=B.|last30= Sturm|first30=E.|display-authors=29|year=2013|doi=10.1088/0067-0049/206/1/1|bibcode = 2013ApJS..206....1S |s2cid=6162900}} incorporating observations with NASA's Great Observatories and other ground and space-based telescopes. Using information from NASA's Spitzer, Hubble, Chandra and Galex observations in a study over 200 of the most luminous infrared selected galaxies in the local universe.{{cite news|title=GOALS|url=http://goals.ipac.caltech.edu/index.html|work=Great Observatories All-sky LIRG Survey|publisher=Caltech|access-date=24 October 2013}} Approximately 180 LIRGs were identified along with over 20 ULIRGs. The LIRGs and ULIRGs targeted in GOALS span the full range of nuclear spectral types (type-1 and type 2 Active Galactic Nuclei, LINERS's, and starbursts) and interaction stages (major mergers, minor mergers, and isolated galaxies).

Some examples of extremely notable LIRGs, ULIRGs, HyLIRGs, ELIRGs

File:PIA19339-MostLuminousGalaxy-WISE-J224607.57-052635.0-20150521.jpg|WISE J224607.57-052635.0 is the most luminous galaxy in the universe. (artist's impression).{{cite web |author=Staff |title=WISE spacecraft discovers most luminous galaxy in universe |url=http://phys.org/news/2015-05-wise-spacecraft-luminous-galaxy-universe.html |date=21 May 2015 |website=PhysOrg |access-date=22 May 2015 }}{{cite web |author=Staff |title=PIA19339: Dusty 'Sunrise' at Core of Galaxy (Artist's Concept) |url=http://photojournal.jpl.nasa.gov/catalog/PIA19339 |date=21 May 2015 |work=NASA |access-date=21 May 2015 }}

File:A very bright contortionist.jpg|South America Galaxy taken by the Hubble Space Telescope{{cite news|title=A very bright contortionist|url=http://www.spacetelescope.org/images/potw1323a/|access-date=14 June 2013|newspaper=ESA/Hubble Picture of the Week|id=potw1323a|date=10 June 2013 |publisher=ESA}}

File:A tale of galactic collisions.jpg|2MASX J05210136-2521450.{{cite news|title=A tale of galactic collisions|url=http://www.spacetelescope.org/images/potw1318a/|access-date=6 May 2013|newspaper=ESA/Hubble Picture of the Week|id=potw1318a|date=6 May 2013 |publisher=ESA}}

File:Potw1245a.tif|Luminous infrared galaxy NGC 5010.{{cite news|title=A galaxy colourfully on the wane ain't dead yet|url=http://www.spacetelescope.org/images/potw1245a/|access-date=12 November 2012|newspaper=ESA/Hubble Picture of the Week|id=potw1245a|date=5 November 2012 |publisher=ESA}}

File:IRAS 19297-0406.jpg|Ultraluminous Infrared Galaxy IRAS 19297-0406

File:Starbursts versus Monsters.jpg|Luminous infrared galaxy MCG-03-04-014{{cite news|title=Starbursts versus Monsters|url=http://www.spacetelescope.org/images/potw1407a/|access-date=12 March 2014|newspaper=ESA / HUBBLE|id=potw1407a|date=17 February 2014 |publisher=ESA}}

{{Reflist}}

• [http://www.spacedaily.com/reports/Nearby_Extreme_Galaxies_Linked_To_Humble_Roots.html Nearby Extreme Galaxies Linked To Humble Roots] (SpaceDaily) Jun 07, 2006
• [http://www.spacedaily.com/reports/How_To_Bake_A_Galaxy.html How To Bake A Galaxy] (SpaceDaily) Jun 19, 2006
• [http://goals.ipac.caltech.edu The Great Observatory All-sky LIRG Survey]

{{Galaxy}}

{{DEFAULTSORT:Luminous Infrared Galaxy}}

Category:Active galaxy types

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