A bright infrared galaxy ( Luminous infrared galaxy , LIRG ) is a galaxy with a luminosity above 10 11 luminosities of the Sun. Such galaxies are more common than galaxies with starbursts , Seyfert galaxies and quasars of comparable luminosities. Infrared galaxies produce more radiation in the infrared of the spectrum than other wavelength ranges.
Galaxies with luminosities higher than 10 12 luminosities of the Sun are called ultraluminous infrared galaxies ( ULIRGs ). Many bright infrared galaxies show signs of interactions and destruction. The rate of star formation can reach 100 stars per year, while in our galaxy an average of one star appears per year.
Even brighter galaxies are called hyper- bright galaxies ( English hyper-luminous infrared galaxies , HLIRGs ).
The galaxies of this type with the highest luminosity are called extremely bright infrared galaxies ( English extremely luminous infrared galaxies , ELIRGs ).
Content
Origin and Evolution
Infrared galaxies look like single gas-rich spiral galaxies, the infrared radiation of which is created mainly during star formation. [1] However, the luminosity of some galaxies is created mainly by the active core of the galaxy (AGN). Such AGNs are located in compact areas in the centers of the galaxy with increased luminosity. AGN radiation is observed in the radio, infrared, visible, ultraviolet, x-ray and gamma ranges of the spectrum. Similar galaxies were discovered in 1983 by observing the IRAS telescope. In some cases, the luminosity of bright infrared galaxies can occur as a result of the presence of both active star formation and AGN. [2]
Bright infrared galaxies emit most of the energy in the infrared part of the spectrum, inaccessible to observation with the naked eye. The total radiated energy is comparable to the energy of quasars, previously considered the most high-energy objects of the Universe. [3]
The reason why it is very difficult to register radiation in the visible part of the spectrum for such galaxies is because they are rich in gas, which absorbs radiation in the visible part of the spectrum and re-emits it in the infrared range. A large proportion of bright infrared galaxies has an active black hole in the central region. Similar galaxies are found in more densely populated areas in the Universe in comparison with ordinary galaxies.
Ultra-Bright Infrared Galaxies
Bright infrared galaxies can probably become ultra-bright over time. Modeling this transition remains difficult. Studies show that ultra-bright infrared galaxies are more likely to contain active nuclei than bright infrared galaxies. [five]
According to one study, the ultra-bright infrared galaxy is just one of the evolutionary stages of galaxy fusion . Two or more spiral galaxies merge with the possible formation of a bright infrared galaxy. At a later stage of the merger, there is a transition to an ultra-bright infrared galaxy. Then it becomes a quasar, eventually becoming an elliptical galaxy . [3] The confirmation of this scenario is the fact that in elliptical galaxies the stars are older than at earlier stages of the scenario.
Extremely bright infrared galaxies
The extremely bright infrared galaxy WISE J224607.57-052635.0 , which has a luminosity of 349 × 10 12 luminosities of the Sun, as of May 2015, was the galaxy with the highest luminosity among all known galaxies. This object belongs to a new class of open WISE galaxies - extremely bright infrared galaxies.
Radiation from WISE J224607.57-052635.0 went to us 12.5 billion years.
There are three reasons why black holes in extremely bright infrared galaxies can be extremely massive. First, the initial black holes may be larger than previously thought possible. Secondly, the Eddington luminosity limit may be violated. When gas falls on a black hole and warms up, radiation is emitted. The radiation pressure ejects the gas outside, which creates restrictions on the rate of absorption of gas by a black hole. If the Eddington limit is overcome, then a black hole can theoretically increase in size relatively quickly. Black holes have already been observed that violate this limit. Thirdly, if a black hole does not rotate very fast, it can absorb matter at a faster pace.
More than 20 extremely bright infrared galaxies have been discovered to date. [6] [7]
Observations
IRAS
The IRAS telescope created the first far-infrared sky survey in 1983. As part of the survey, tens of thousands of galaxies were discovered, many of which were not found in previous surveys. According to IRAS, scientists were able to determine the luminosity of the observed objects. During the mission, which lasted 10 months, about 250 thousand infrared sources were discovered.
GOALS
Great Observatories All-sky LIRG Survey (GOALS) is a multi-wavelength survey of bright infrared galaxies, [8] including observations of the Large Observatories and other space and ground-based telescopes. For the 200 brightest infrared galaxies of the near part of the Universe, observations were obtained with the Spitzer , Hubble , Chandra and Galex telescopes. [9] About 180 bright and 20 ultra-bright infrared galaxies were identified. The studied galaxies include examples of all types of galactic nuclei (two types of active galactic nuclei, LINER , regions with starburst flares) and various stages of interaction (large and small fusions, isolated galaxies).
Examples
Some examples of bright infrared galaxies.
| Galaxy | Type of | Luminosity | Constellation | RA | Dec | Notes | |
|---|---|---|---|---|---|---|---|
| WISE J224607.57-052635.0 | ELIRG | 22 h 46 m 07.57 s | -05 ° 26 ′ 35.0 ″ | Opened in 2015, as of May 2015, it was the brightest of the known galaxies. | [ten] | ||
| II Zw 96 | Lirg | pair of galaxies in the process of merger | |||||
| NGC 6240 | ULIRG | Ophiuchus | Nearly Infrared Galaxy Explored in Detail | ||||
| Arp 220 | ULIRG | nearest ultra-bright infrared galaxy, fusion of two galaxies continues |
Gallery
WISE J224607.57-052635.0 as presented by the artist. [11] [12]
Galaxy South America [13]
2MASX J05210136-2521450 . [14]
NGC 5010 . [15]
Ultra-bright infrared galaxy IRAS 19297-0406
Bright Infrared Galaxy MCG-03-04-014 [16]
Notes
- ↑ Luminous Infrared Galaxies . Date of treatment October 23, 2013.
- ↑ The AGN-Starburst Connection in Warm Infrared Galaxies . Archived on September 24, 2015.
- ↑ 1 2 The Curious History of Luminous Infrared Galaxies .
- ↑ When galaxies collide . www.spacetelescope.org . Date of treatment January 10, 2017.
- ↑ Star-formation, AGN and Ultra-luminous infrared galaxies . Date of treatment November 12, 2013.
- ↑ NASA's WISE Spacecraft Discovers Most Luminous Galaxy in Universe . Date of appeal May 25, 2015.
- ↑ Tsai, Chao-Wei; Eisenhardt, Peter; Wu, Jingwen; Stern, Daniel; Assef, Roberto; Blain, Andrew; Bridge, Carrie; Benford, Dominic; Cutri, Roc. The Most Luminous Galaxies Discovered by WISE // The Astrophysical Journal : journal. - IOP Publishing , 2014 .-- October 7 ( vol. 805 , no. 2 ). - P. 90 . - DOI : 10.1088 / 0004-637X / 805/2/90 . - . - arXiv : 1410.1751 .
- ↑ Stierwalt, S .; Armus, L .; Surace, JA; Inami, H .; Petric, AO; Diaz-Santos, T .; Haan, S .; Charmandaris, V .; Howell, J .; Kim, DC; Marshall, J .; Mazzarella, JM; Spoon, HWW; Veilleux, S .; Evans, A .; Sanders, DB; Appleton, P .; Bothun, G .; Bridge, CR; Chan, B .; Frayer, D .; Iwasawa, K .; Kewley, LJ; Lord, S .; Madore, BF; Melbourne, JE; Murphy, EJ; Rich, JA; Schulz, B .; Sturm, E. Mid-Infrared Properties of Nearby Luminous Infrared Galaxies I: Spitzer IRS Spectra for the GOALS sample (Eng.) // The Astrophysical Journal : journal. - IOP Publishing 2013. - Vol. 206 . - P. 1 . - DOI : 10.1088 / 0067-0049 / 206/1/1 . - . - arXiv : 1302.4477 .
- ↑ GOALS . Date of treatment October 24, 2013.
- ↑ Most Luminous Galaxy in Universe Discovered , Science Daily (May 21, 2015).
- ↑ Staff. WISE spacecraft discovers most luminous galaxy in universe . PhysOrg (May 21, 2015). Date of treatment May 22, 2015.
- ↑ Staff. PIA19339: Dusty 'Sunrise' at Core of Galaxy (Artist's Concept) . NASA (May 21, 2015). Date of treatment May 21, 2015.
- ↑ A very bright contortionist . Date of treatment June 14, 2013.
- ↑ A tale of galactic collisions . Date of treatment May 6, 2013.
- ↑ A galaxy colorfully on the wane ain't dead yet . Date of treatment November 12, 2012.
- ↑ Starbursts versus Monsters . Date of treatment March 12, 2014.
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