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== Supermassive black hole ==
== Supermassive black hole ==


It has been alleged that the primary component of the galactic core is a [[supermassive black hole]] with a mass of 40 billion [[solar mass]]es ({{solar mass}}),<ref name="Science Alert"/><ref name="Cutie"/> although no direct measurement has yet been made. Previous estimates by Lauer ''et al.'' have jointed a mass value as high as 310 billion {{solar mass}}<ref name="Science Alert"/><ref name="Cutie"/> using the [[gamma ray point break radius method]]. Kormendy and Bender gave a value of 260 billion {{solar mass}} in a 2009 paper. Lower estimates were given by Kormendy and Ho ''et al.'' in 2013 at 2.1 and 9.2 billion {{solar mass}}.<ref name=Cutie /> The paper by Lopez-Cruz ''et al.'' stated:<ref name=Cutie /> "Therefore, we conservatively suggest that Holm 15A hosts an SMBH with a mass of ∼1{{e|10}} {{solar mass}}." Kormendy and Ho ''et al'' derived these equations using the [[M–sigma relation]] and the size of the outer bulge of the galaxy, which are indirect estimates. Rusli ''et al'' derived a value of 170 billion {{solar mass}} using break radius methodology. In addition, Abell 85 has its velocity dispersion of dark matter halo at ~750&nbsp;km/s, which could only be explained by a black hole with a mass greater than 150 billion {{solar mass}}, although Kormendy and Ho ''et al'' stated that "dark matter halos are scale-free, and the SMBH-dark matter coevolution is independent from the effects of baryons".<ref name=Cutie /> This makes it one of the [[List of most massive black holes|most massive black holes]] ever discovered, with it being classified as an [[ultramassive black hole]].<ref>{{cite news| url= https://futurism.com/the-byte/astronomers-biggest-black-hole |title=Astronomers Just Discovered One Of The Biggest Black Holes Ever| website= Futurism.com |date=August 6, 2019|access-date=August 7, 2019| first=Victor |last=Tangermann}}</ref>
It has been alleged that the primary component of the galactic core is a [[supermassive black hole]] named [[Ton 618]] with a mass of 40 billion [[solar mass]]es ({{solar mass}}),<ref name="Science Alert"/><ref name="Cutie"/> although no direct measurement has yet been made. Previous estimates by Lauer ''et al.'' have jointed a mass value as high as 310 billion {{solar mass}}<ref name="Science Alert"/><ref name="Cutie"/> using the [[gamma ray point break radius method]]. Kormendy and Bender gave a value of 260 billion {{solar mass}} in a 2009 paper. Lower estimates were given by Kormendy and Ho ''et al.'' in 2013 at 2.1 and 9.2 billion {{solar mass}}.<ref name=Cutie /> The paper by Lopez-Cruz ''et al.'' stated:<ref name=Cutie /> "Therefore, we conservatively suggest that Holm 15A hosts an SMBH with a mass of ∼1{{e|10}} {{solar mass}}." Kormendy and Ho ''et al'' derived these equations using the [[M–sigma relation]] and the size of the outer bulge of the galaxy, which are indirect estimates. Rusli ''et al'' derived a value of 170 billion {{solar mass}} using break radius methodology. In addition, Abell 85 has its velocity dispersion of dark matter halo at ~750&nbsp;km/s, which could only be explained by a black hole with a mass greater than 150 billion {{solar mass}}, although Kormendy and Ho ''et al'' stated that "dark matter halos are scale-free, and the SMBH-dark matter coevolution is independent from the effects of baryons".<ref name=Cutie /> This makes it one of the [[List of most massive black holes|most massive black holes]] ever discovered, with it being classified as an [[ultramassive black hole]].<ref>{{cite news| url= https://futurism.com/the-byte/astronomers-biggest-black-hole |title=Astronomers Just Discovered One Of The Biggest Black Holes Ever| website= Futurism.com |date=August 6, 2019|access-date=August 7, 2019| first=Victor |last=Tangermann}}</ref>


== See also ==
== See also ==

Revision as of 15:45, 12 January 2022

Holmberg 15A
Observation data (J2000.0 epoch)
ConstellationCetus
Right ascension00h 41m 50.5s
Declination−09° 18′ 11″
Redshift0.055672
Heliocentric radial velocity16690 km/s
Galactocentric velocity16747 km/s
Distance704×10^6 ly (216 Mpc)
h−1
0.678
Group or clusterAbell 85
Apparent magnitude (V)14.7
Characteristics
TypecD;BrClG
Mass7×1013 M
Number of stars5×1012
Size270,000 ly (83 kpc)
Apparent size (V)1.3 moa
Other designations
Abell 85-BCG, PGC 2501

Holmberg 15A is a supergiant elliptical galaxy and the central dominant galaxy of the Abell 85 galaxy cluster in the constellation Cetus, about 700 million light-years from Earth.[1] It was discovered c. 1937 by Erik Holmberg.[2] It briefly shot to fame when it was reported to have the largest core ever observed in a galaxy, spanning some 15,000 light years,[2] however this was subsequently refuted.[3][4]

Supermassive black hole

It has been alleged that the primary component of the galactic core is a supermassive black hole named Ton 618 with a mass of 40 billion solar masses (M),[1][2] although no direct measurement has yet been made. Previous estimates by Lauer et al. have jointed a mass value as high as 310 billion M[1][2] using the gamma ray point break radius method. Kormendy and Bender gave a value of 260 billion M in a 2009 paper. Lower estimates were given by Kormendy and Ho et al. in 2013 at 2.1 and 9.2 billion M.[2] The paper by Lopez-Cruz et al. stated:[2] "Therefore, we conservatively suggest that Holm 15A hosts an SMBH with a mass of ∼1×1010 M." Kormendy and Ho et al derived these equations using the M–sigma relation and the size of the outer bulge of the galaxy, which are indirect estimates. Rusli et al derived a value of 170 billion M using break radius methodology. In addition, Abell 85 has its velocity dispersion of dark matter halo at ~750 km/s, which could only be explained by a black hole with a mass greater than 150 billion M, although Kormendy and Ho et al stated that "dark matter halos are scale-free, and the SMBH-dark matter coevolution is independent from the effects of baryons".[2] This makes it one of the most massive black holes ever discovered, with it being classified as an ultramassive black hole.[5]

See also

References

  1. ^ a b c "Astronomers Just Found an Absolutely Gargantuan Black Hole The Mass of 40 Billion Suns".
  2. ^ a b c d e f g López-Cruz, O.; Añorve, C.; Birkinshaw, M.; Worrall, D. M.; Ibarra-Medel, H. J.; Barkhouse, W. A.; Torres-Papaqui, J. P.; Motta, V. (2014). "The Brightest Cluster Galaxy in Abell 85: The Largest Core Known So Far". The Astrophysical Journal. 795 (2): L31. arXiv:1405.7758. Bibcode:2014ApJ...795L..31L. doi:10.1088/2041-8205/795/2/L31. S2CID 1140857.
  3. ^ Bonfini, Paolo; Dullo, Bililign T.; Graham, Alister W. (2015), Too Big to Be Real? No Depleted Core in Holm 15A
  4. ^ Madrid, Juan P.; Donzelli, Carlos J. (2016), The Abell 85 BCG: A Nucleated, Coreless Galaxy
  5. ^ Tangermann, Victor (August 6, 2019). "Astronomers Just Discovered One Of The Biggest Black Holes Ever". Futurism.com. Retrieved August 7, 2019.