NGC 3862 is an elliptical galaxy located 300 million

light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Leo Leo or Léo may refer to: Acronyms * Law enforcement officer * Law enforcement organisation * ''Louisville Eccentric Observer'', a free weekly newspaper in Louisville, Kentucky * Michigan Department of Labor and Economic Opportunity Arts an ...

. Discovered by astronomer William Herschel on April 27, 1785, NGC 3862 is an outlying member of the

Leo Cluster The Leo Cluster ( Abell 1367) is a galaxy cluster about 330 million light-years distant ( z = 0.022) in the constellation Leo, with at least 70 major galaxies. The galaxy known as NGC 3842 is the brightest member of this cluster. Along with the ...

. The galaxy is classified as a FR I radio galaxy and as a Head-tail radio galaxy. It hosts a supermassive black hole that is blasting a jet of

plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...

that is moving at 98 percent of the speed of light and is one of the few jets that can be seen in visible light.

Jet

Observations made by Bridle et al. in 1981 using maps made with the

VLA VLA or vla may refer to: Organizations * Vermont Library Association, professional organization for librarians from Vermont * Veterinary Laboratories Agency, a UK government agency for researching animal and public health * Victoria Legal Aid, an ...

revealed a jet-like structure emerging from the nucleus of NGC 3862. In late January 1992, the Hubble Space Telescope observed NGC 3862 with the Faint Object Spectrograph and confirmed the presence of an optical jet in the nucleus of NGC 3862. Hs-2015-19-a-small_web

The optical jet, which has a measured length of , appears to expand slowly and dims in peak and integrated brightness within the interior of the apparent ring of dust. Within distances of about , the jet appears narrow and well-collimated. At a distance of the jet starts to abruptly expand and becomes turbulent. At this distance, filaments and pronounced kinks can be observed which suggests that the jet is oscillating or evolving a helical structure. After crossing the ring at a distance of around , the jet widens dramatically, changes direction, and dims more rapidly both in peak and integrated brightness and becomes more diffuse in appearance. This suggests that the jet is interacting with the dust ring and becomes less collimated. However, Perlman et al. suggests that the disk and the jet occupy physically distinct regions of the galaxy and therefore are not interacting. The total amount of energy produced by the jet is estimated to be around 3.71 × 10⁴² ergs.

Knots

The jet of NGC 3862 contains four faint knots of material designated in increasing order from the nucleus: Knot A, B, C and D. The knots exhibit a structure similar to that of a string of pearls.

Radio morphology

NGC 3862 contains a Head-tail radio morphology with two tails that extend . This morphology appears to be the result of the galaxy interacting with the intracluster medium (ICM).

Nucleus

The central region of NGC 3862 appears host a nearly face-on disk of dust with a diameter of . However, as the jet of galaxy has been suggested to lie at angle of 50° to Earth's line of sight, the dust disk must be ''puffed up'' in order for the jet to have been disturbed by the disk. The emission of CO in the nucleus exhibits a double-horned line profile which suggests that the dust disk is rotating. The inferred distribution of the CO is consistent with the observed dust disk and the presence of the molecular gas suggests that the gas originated from either a

merger Mergers and acquisitions (M&A) are business transactions in which the ownership of companies, other business organizations, or their operating units are transferred to or consolidated with another company or business organization. As an aspect ...

with two gas-rich galaxies a few billion years ago or from cannibalism of smaller gas-rich galaxies. Hutchings et al. proposed instead that the apparent disk represents an evacuated region cleared of dust by some nuclear related process or by the jet itself as indicated by the color of the region inside the ring being similar to the color of the galaxy spectrum. Lara et al. also suggested this as the jet appears to widen within the apparent ring which would be consistent with an explanation of a favored expansion of the jet due to the lower density medium within the evacuated region or bubble.

Supermassive black hole

NGC 3862 contains a supermassive black hole with an estimated mass of

M☉ The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass of ...

. The black hole is responsible for producing the jet of

that is moving at nearly the speed of light.

Companion galaxies

NGC 3862 has an elliptical or a

lenticular Lenticular is an adjective often relating to lenses. It may refer to: * A term used with two meanings in botany: see * Lenticular cloud, a lens-shaped cloud * Lenticular galaxy, a lens-shaped galaxy * Lenticular (geology), adjective describing a ...

companion galaxy known as IC 2955. It lies about from NGC 3862.

References

External links

{{Ngc40 036606 3862 Elliptical galaxies Leo (constellation) Radio galaxies 06723 Leo Cluster Astronomical objects discovered in 1785

264 __NOTOC__ Year 264 ( CCLXIV) was a leap year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Gallienus and Saturninus (or, less frequently, year 1017 '' ...

+19.40

Jet