TON 618
| TON 618 | |
|---|---|
| Observation data (Epoch ) | |
| Constellation | Canes Venatici |
| Right ascension | 12h 28m 24.9s[1] |
| Declination | +31° 28′ 38″[1] |
| Redshift | 2.219[1] |
| Distance | 3.18 Gpc (10.4 Gly)[1] |
| Type | Quasar[1] |
| Apparent magnitude (V) | 15.9[1] |
| Notable features | Hyperluminous quasar |
| Other designations | |
| FBQS J122824.9+312837, B2 1225+31, B2 1225+317, 7C 1225+3145[1] | |
| See also: Quasar, List of quasars | |
TON 618 is a very distant and extremely luminous quasar—technically, a hyperluminous, broad-absorption line, radio-loud quasar—located near the North Galactic Pole in the constellation Canes Venatici. It contains one of the most massive known black holes, with a mass of 66 billion M☉.[2]
Observational history
Because quasars were not recognized until 1963,[3] the nature of this object was unknown when it was first noted in a 1957 survey of faint blue stars (mainly white dwarfs) that lie away from the plane of the Milky Way. On photographic plates taken with the 0.7 m Schmidt telescope at the Tonantzintla Observatory in Mexico, it appeared "decidedly violet" and was listed as number 618 in the Tonantzintla catalogue.[4]
In 1970, a radio survey at Bologna discovered radio emission from TON 618, indicating that it was a quasar.[5] Marie-Helene Ulrich then obtained optical spectra of TON 618 at the McDonald Observatory which showed emission lines typical of a quasar. From the redshift of the lines Ulrich deduced that TON 618 was very distant, and hence was one of the most luminous quasars known.[6]
Supermassive black hole
As a quasar, TON 618 is believed to be an accretion disc of intensely hot gas swirling around a giant black hole in the center of a galaxy. The light originating from the quasar is estimated to be 10.4 billion years old. The surrounding galaxy is not visible from Earth, because the quasar itself outshines it. With an absolute magnitude of −30.7, it shines with a luminosity of 4×1040 watts, or as brilliantly as 140 trillion Suns, making it one of the brightest objects in the known Universe.[1]
Like other quasars, TON 618 has a spectrum containing emission lines from cooler gas much further out than the accretion disc, in the broad-line region. The emission lines in the spectrum of TON 618 are unusually wide,[6] indicating that the gas is travelling very fast; the hydrogen beta line shows it is moving around at 7000 km/s.[2] Hence the central black hole must be exerting a particularly strong gravitational force.
The size of the broad-line region can be calculated from the brightness of the quasar radiation that is lighting it up.[7] From the size of this region and the speed it is orbiting, the law of gravity reveals that the mass of the black hole in TON 618 is 66 billion solar masses.[2] With a mass this high, TON 618 falls into the new classification of ultramassive black holes.[8][9] A black hole of this mass has a Schwarzschild radius of 1,300 AU (about 390 billion km in diameter, more than 40 times the size of Neptune's orbit).
See also
References
- ^ a b c d e f g h "NED results for object TON 618". NASA/IPAC EXTRAGALACTIC DATABASE.
- ^ a b c Shemmer, O.; Netzer, H.; Maiolino, R.; Oliva, E.; Croom, S.; Corbett, E.; di Fabrizio, L. (2004). "Near-infrared spectroscopy of high-redshift active galactic nuclei: I. A metallicity-accretion rate relationship". The Astrophysical Journal. 614 (2): 547–557. arXiv:astro-ph/0406559. Bibcode:2004ApJ...614..547S. doi:10.1086/423607.
- ^ "1963: Maarten Schmidt Discovers Quasars". Observatories of the Carnegie Institution for Science. Retrieved 21 October 2017.
- ^ Iriarte, Braulio; Chavira, Enrique (1957). "Blue stars in the North Galactic Cap" (PDF). Boletín de los Observatorios de Tonantzintla y Tacubaya. 2 (16): 3–36. Retrieved 21 October 2017.
{{cite journal}}: External link in|issue= - ^ Colla, G.; Fanti, C.; Ficarra, A.; Formiggini, L.; Gandolfi, E.; Grueff, G.; Lari, C.; Padrielli, L.; Roffi, G.; Tomasi, P; Vigotti, M. (1970). "A catalogue of 3235 radio sources at 408 MHz". Astronomy & Astrophysics Supplement Series. 1 (3): 281. Bibcode:1970A&AS....1..281C.
- ^ a b Ulrich, Marie-Helene (1976). "Optical spectrum and redshifts of a quasar of extremely high intrinsice luminosity: B2 1225+31". The Astrophysical Journal. 207: L73–L74. Bibcode:1976ApJ...207L..73U. doi:10.1086/182182.
- ^ Kaspi, Shai; Smith, Paul S.; Netzer, Hagai; Maos, Dan; Jannuzi, Buell T.; Giveon, Uriel (2000). "Reverberation measurements for 17 quasars and the size-mass-luminosity relations in active galactic nuclei". The Astrophysical Journal. 533 (2): 631–649. arXiv:astro-ph/9911476. Bibcode:2000ApJ...533..631K. doi:10.1086/308704.
- ^ Irving, Michael (21 February 2018). ""Ultramassive" black holes may be the biggest ever found – and they're growing fast". New Atlas.
- ^ "From Super to Ultra: Just How Big Can Black Holes Get?". NASA – Chandra X-Ray Observatory. 18 December 2012.
