NGC 3862 is an

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 three main galaxy morphological classification, classes of galaxy described by Edwin Hubble in his Hub ...

located 300 million

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

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 first constellati ...

Leo Leo is the Latin word for lion. It most often refers to: * Leo (constellation), a constellation of stars in the night sky * Leo (astrology), an astrological sign of the zodiac * Leo (given name), a given name in several languages, usually mas ...

. Discovered by astronomer

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

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 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 ...

that is blasting a jet of plasma that is moving at 98 percent of the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant exactly equal to ). It is exact because, by international agreement, a metre is defined as the length of the path travelled by light in vacuum during a time i ...

and is one of the few jets that can be seen in

visible light Light, visible light, or visible radiation is electromagnetic radiation that can be perceived by the human eye. Visible light spans the visible spectrum and is usually defined as having wavelengths in the range of 400–700 nanometres (nm ...

. One

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

has been observed in NGC 3862: SN 2023bqk ( type Ia-pec, mag. 18.3).

Jet

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

VLA ''Vla'' () is a Dutch dairy product made from fresh milk. The word ''vla'' was first documented in the 13th century and originally referred to any custard-like substance covering cakes or other baked goods. The word '' vlaai'' is related and ...

revealed a jet-like structure emerging from the nucleus of NGC 3862. In late January 1992, the

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

observed NGC 3862 with the

Faint Object Spectrograph The Faint Object Spectrograph (FOS) was a spectrograph installed on the Hubble Space Telescope. It was replaced by the Space Telescope Imaging Spectrograph in 1997, and is now on display in the National Air and Space Museum The National Air a ...

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 The erg is a unit of energy equal to 10−7joules (100 nJ). It is not an SI unit, instead originating from the centimetre–gram–second system of units (CGS). Its name is derived from (), a Greek word meaning 'work' or 'task'. An erg is the ...

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 In astronomy, the intracluster medium (ICM) is the superheated plasma (physics), plasma that permeates a galaxy cluster. The gas consists mainly of ionized hydrogen and helium and accounts for most of the baryonic material in galaxy clusters. The ...

(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 Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

'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 a company, business organization, or one of their operating units is transferred to or consolidated with another entity. They may happen through direct absorpt ...

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

with an estimated mass of

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

. The black hole is responsible for producing the jet of plasma 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 Lens (optics), 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 de ...

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 (Roman numerals, CCLXIV) was a leap year starting on Friday 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 ''Ab urbe condita''). The ...

+19.40

Jet