APM 08279+5255 is a very distant, broad absorption line quasar located in the constellation Lynx. It is magnified and split into multiple images by the

gravitational lens A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This effect is known ...

ing effect of a foreground galaxy through which its light passes. It appears to be a giant

elliptical galaxy An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The Real ...

with a

supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions of times the mass of the Sun (). Black holes are a class of astronomical ob ...

and associated accretion disk. It possesses large regions of hot dust and molecular gas, as well as regions with starburst activity.

Gravitational lensing

APM 08279+5255 was initially identified as a quasar in 1998 during an Automatic Plate Measuring Facility (APM) survey to find carbon stars in the

galactic halo A galactic halo is an extended, roughly spherical component of a galaxy which extends beyond the main, visible component. Several distinct components of galaxies comprise the halo: * the stellar halo * the galactic corona (hot gas, i.e. a plas ...

. The combination of its high redshift (z=3.87) and brightness (particularly in the infrared) made it the most luminous object yet seen in the universe. It was suspected of being a gravitationally lensed object, with its luminosity magnified. Observations in the infrared with the NICMOS high-resolution camera on board the

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...

(HST) showed that the source was composed of three discrete images. Even accounting for the magnification, the quasar is an extremely powerful object, with a luminosity of 10¹⁴ to 10¹⁵ times the luminosity of the sun. Subsequent observations with the Hubble

Space Telescope Imaging Spectrograph The Space Telescope Imaging Spectrograph (STIS) is a spectrograph, also with a camera mode, installed on the Hubble Space Telescope. Aerospace engineer Bruce Woodgate of the Goddard Space Flight Center was the principal investigator and crea ...

confirmed the presence of a third faint image between the two brighter images. Each component has the same spectral energy distribution and is an image of the quasar. Gravitational lensed systems with odd numbers of images are extremely rare; most contain two or four. Initially the magnification due to gravitational lensing was thought to be large, in the range of 40 to 90 times. After detailed observations at many wavelengths, the best model of the lensing galaxy is a tilted spiral galaxy. This gives a magnification of about 4. The additional observations led to a revised redshift of 3.911.

Galactic structure

APM 08279+5255 is a bright source at almost all wavelengths and has become one of the most studied of distant sources. Using interferometry it has been mapped in

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

with the AXAF CCD Imaging Spectrometer on the

Chandra X-ray Observatory The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources 1 ...

, in

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

with the Hubble Space Telescope, and in

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmi ...

with the

Very Long Baseline Array The Very Long Baseline Array (VLBA) is a system of ten radio telescopes which are operated remotely from their Array Operations Center located in Socorro, New Mexico, as a part of the National Radio Astronomy Observatory (NRAO). These ten radi ...

. Measurements with the IRAM Plateau de Bure Interferometer and other instruments looked at the distribution of molecules such as CO, CN, HCN, and HCO+ as well as atomic

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...

. From these observations APM 08279+5255 is a giant elliptical galaxy with large amounts of gas and dust and an

active galactic nucleus An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not prod ...

(AGN) at its core. The AGN is radio-quiet with no evidence for a relativistic jet. It is powered by one of the largest known supermassive black holes: 23 billion solar masses (based on the molecular disk velocities); or alternatively 10 billion solar masses (based on

reverberation mapping Reverberation mapping (or Echo mapping) is an astrophysical technique for measuring the structure of the broad-line region (BLR) around a supermassive black hole at the center of an active galaxy, and thus estimating the hole's mass. It is consid ...

). The black hole is surrounded by an accretion disk of material spiraling into it, a few

parsec The parsec (symbol: pc) is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to or (au), i.e. . The parsec unit is obtained by the use of parallax and trigonometry, an ...

s in size. Further out is a dust torus, a doughnut shaped cloud of dust and gas with a radius of about 100 parsecs. Both the accretion disk and dust torus appear to be almost face-on to us. The radiation from the molecular gas is coming from a flattened disk at the center of the galaxy with a radius of 550 pc. This is also the

starburst region A starburst is an astrophysical process that involves star formation occurring at a rate that is large compared to the rate that is typically observed. This starburst activity will consume the available interstellar gas supply over a timespan that ...

of the galaxy. The gas is heated both by activity in the AGN and by the newly forming stars. APM is an ultra-luminous infrared galaxy (ULIRG). Its high redshift shifts the far-infrared spectrum into millimeter wavelengths where it can be observed from observatories on the ground. In 2008 and 2009 the intensities of its

water vapor (99.9839 °C) , - , Boiling point , , - , specific gas constant , 461.5 J/( kg·K) , - , Heat of vaporization , 2.27 MJ/kg , - , Heat capacity , 1.864 kJ/(kg·K) Water vapor, water vapour or aqueous vapor is the gaseous p ...

spectral line A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to iden ...

s were measured using the millimeter wave spectrometer Z-Spec at the

Caltech Submillimeter Observatory The Caltech Submillimeter Observatory (CSO) was a 10.4-meter (34 ft) diameter submillimeter wavelength telescope situated alongside the 15-meter (49 ft) James Clerk Maxwell Telescope (JCMT) at Mauna Kea Observatories. It was engaged in ...

. Comparing the spectrum to that of

Markarian 231 Markarian 231 (UGC 8058) is a Type-1 Seyfert galaxy that was discovered in 1969 as part of a search of galaxies with strong ultraviolet radiation. It contains the nearest known quasar. Markarian 231 is located about 581 million light years away f ...

, another ULIRG, showed that it had 50 times the water vapor of that galaxy. This made it the largest mass of water in the known universe—100 trillion times more water than that held in all of Earth's oceans combined. Its discovery shows that water has been prevalent in the known universe for nearly its entire existence; the radiation was emitted 1.6 billion years after the Big Bang.

Gallery

File:quasar Mark Johnston.jpg, Amateur astronomer photo of APM 08279+5255

References

External links

* {{cite web , title=APM 08279+5255: Matter Near Black Hole Gets Second Lease On Life , url=http://chandra.harvard.edu/photo/2003/apm08279/ , work=Chandra X-ray Observatory: Photo Album , publisher=Harvard-Smithsonian Center for Astrophysics , date=25 March 2003 , accessdate=27 April 2014 Lynx (constellation) Quasars Gravitational lensing Gravitationally lensed quasars IRAS catalogue objects Starburst galaxies Supermassive black holes