Astrophysical jet

{{anchor|Relativistic jet}}

File:M87 jet.jpg emitting a relativistic jet, as seen by the Hubble Space Telescope]]

Relativistic jets are beams of ionised matter accelerated close to the speed of light. Most have been observationally associated with central black holes of some active galaxies, radio galaxies or quasars, and also by galactic stellar black holes, neutron stars or pulsars. Beam lengths may extend between several thousand,

{{Cite web

|last=Biretta |first=J.

|date=6 Jan 1999

|title=Hubble Detects Faster-Than-Light Motion in Galaxy M87

|url=http://www.stsci.edu/ftp/science/m87/m87.html

}} hundreds of thousands

{{cite web

|title=Evidence for Ultra-Energetic Particles in Jet from Black Hole

|url=http://news.yale.edu/2006/06/20/evidence-ultra-energetic-particles-jet-black-hole

|date=20 June 2006

|publisher=Yale University – Office of Public Affairs

|archive-url=https://web.archive.org/web/20080513034113/http://www.yale.edu/opa/newsr/06-06-20-01.all.html

|archive-date=2008-05-13

}} or millions of parsecs. Jet velocities when approaching the speed of light show significant effects of the special theory of relativity; for example, relativistic beaming that changes the apparent beam brightness.

{{cite journal

|last1=Semenov |first1=V.

|last2=Dyadechkin |first2=S.

|last3=Punsly |first3=B.

|year=2004

|title=Simulations of Jets Driven by Black Hole Rotation

|journal=Science

|volume=305 |issue=5686 |pages=978–980

|arxiv=astro-ph/0408371

|bibcode=2004Sci...305..978S

|doi=10.1126/science.1100638

|pmid=15310894

|s2cid=1590734

|url=https://cds.cern.ch/record/789685

}}

Massive central black holes in galaxies have the most powerful jets, but their structure and behaviours are similar to those of smaller galactic neutron stars and black holes. These SMBH systems are often called microquasars and show a large range of velocities. SS 433 jet, for example, has a mean velocity of 0.26c.{{cite journal |last1=Blundell |first1=Katherine |title=Jet Velocity in SS 433: Its Anticorrelation with Precession-Cone Angle and Dependence on Orbital Phase |journal=The Astrophysical Journal |date=December 2008 |volume=622 |issue=2 |page=129 |doi=10.1086/429663 |arxiv=astro-ph/0410457 |url=https://www.researchgate.net/publication/230936232 |access-date=15 January 2021|doi-access=free }} Relativistic jet formation may also explain observed gamma-ray bursts, which have the most relativistic jets known, being ultrarelativistic.{{Cite journal |last1=Dereli-Bégué |first1=Hüsne |last2=Pe’er |first2=Asaf |last3=Ryde |first3=Felix |last4=Oates |first4=Samantha R. |last5=Zhang |first5=Bing |last6=Dainotti |first6=Maria G. |date=2022-09-24 |title=A wind environment and Lorentz factors of tens explain gamma-ray bursts X-ray plateau |journal=Nature Communications |language=en |volume=13 |issue=1 |pages=5611 |doi=10.1038/s41467-022-32881-1 |pmid=36153328 |pmc=9509382 |arxiv=2207.11066 |bibcode=2022NatCo..13.5611D |issn=2041-1723}}

Mechanisms behind the composition of jets remain uncertain,

{{Cite journal

|last1=Georganopoulos |first1=M.

|last2=Kazanas |first2=D.

|last3=Perlman |first3=E.

|last4=Stecker |first4=F. W.

|year=2005

|title=Bulk Comptonization of the Cosmic Microwave Background by Extragalactic Jets as a Probe of Their Matter Content

|journal=The Astrophysical Journal

|volume=625 |issue=2 |pages=656–666

|arxiv=astro-ph/0502201

|bibcode=2005ApJ...625..656G

|doi=10.1086/429558

|s2cid=39743397

}} though some studies favour models where jets are composed of an electrically neutral mixture of nuclei, electrons, and positrons, while others are consistent with jets composed of positron–electron plasma.

{{cite journal

|last1=Hirotani |first1=K.

|last2=Iguchi |first2=S.

|last3=Kimura |first3=M.

|last4=Wajima |first4=K.

|year=2000

|title=Pair Plasma Dominance in the Parsec-Scale Relativistic Jet of 3C 345

|journal=The Astrophysical Journal

|volume=545 |issue=1 |pages=100–106

|bibcode=2000ApJ...545..100H

|doi=10.1086/317769

|arxiv = astro-ph/0005394 |s2cid=17274015

}}[http://pc.astro.brandeis.edu/pdfs/elec-pos.pdf Electron–positron Jets Associated with Quasar 3C 279]{{cite web

|last1=Naeye |first1=R.

|last2=Gutro |first2=R.

|date=2008-01-09

|title=Vast Cloud of Antimatter Traced to Binary Stars

|url=http://www.nasa.gov/centers/goddard/news/topstory/2007/antimatter_binary.html

|publisher=NASA

}} Trace nuclei swept up in a relativistic positron–electron jet would be expected to have extremely high energy, as these heavier nuclei should attain velocity equal to the positron and electron velocity.

Because of the enormous amount of energy needed to launch a relativistic jet, some jets are possibly powered by spinning black holes. However, the frequency of high-energy astrophysical sources with jets suggests combinations of different mechanisms indirectly identified with the energy within the associated accretion disk and X-ray emissions from the generating source. Two early theories have been used to explain how energy can be transferred from a black hole into an astrophysical jet:

• Blandford–Znajek process.

{{Cite journal

|last1=Blandford |first1=R. D.

|last2=Znajek |first2=R. L.

|year=1977

|title=Electromagnetic extraction of energy from Kerr black holes

|journal=Monthly Notices of the Royal Astronomical Society

|volume=179 |issue=3 |pages=433

|bibcode=1977MNRAS.179..433B

|doi=10.1093/mnras/179.3.433

|doi-access=free

|arxiv=astro-ph/0506302}} This theory explains the extraction of energy from magnetic fields around an accretion disk, which are dragged and twisted by the spin of the black hole. Relativistic material is then feasibly launched by the tightening of the field lines.

• Penrose mechanism.

{{cite journal

|last1=Penrose |first1=R.

|year=1969

|title=Gravitational Collapse: The Role of General Relativity

|journal=Rivista del Nuovo Cimento

|volume=1 |pages=252–276

|bibcode=1969NCimR...1..252P

}} Reprinted in: {{cite journal

|last1=Penrose |first1=R.

|year=2002

|title="Golden Oldie": Gravitational Collapse: The Role of General Relativity

|journal=General Relativity and Gravitation

|volume=34 |issue=7 |pages=1141–1165

|bibcode=2002GReGr..34.1141P

|doi=10.1023/A:1016578408204

|s2cid=117459073

}} Here energy is extracted from a rotating black hole by frame dragging, which was later theoretically proven by Reva Kay Williams to be able to extract relativistic particle energy and momentum,

{{Cite journal

|last=Williams |first=R. K.|author-link=Reva Williams

|year=1995

|title=Extracting X-rays, Ύ-rays, and relativistic e⁻e⁺ pairs from supermassive Kerr black holes using the Penrose mechanism

|journal=Physical Review

|volume=51 |issue=10 |pages=5387–5427

|bibcode=1995PhRvD..51.5387W

|doi=10.1103/PhysRevD.51.5387

|pmid=10018300

}} and subsequently shown to be a possible mechanism for jet formation.

{{Cite journal

|last1=Williams |first1=R. K.

|year=2004

|title=Collimated Escaping Vortical Polar e−e+Jets Intrinsically Produced by Rotating Black Holes and Penrose Processes

|journal=The Astrophysical Journal

|volume=611 |issue=2 |pages=952–963

|arxiv=astro-ph/0404135

|bibcode=2004ApJ...611..952W

|doi=10.1086/422304

|s2cid=1350543

}} This effect includes using general relativistic gravitomagnetism.

File:Lighthouse nebula.jpg

Jets may also be observed from spinning neutron stars. An example is pulsar IGR J11014-6103, which has the largest jet so far observed in the Milky Way, and whose velocity is estimated at 80% the speed of light (0.8c). X-ray observations have been obtained, but there is no detected radio signature nor accretion disk.

{{cite web

|url=http://chandra.harvard.edu/photo/2012/igrj11014/

|title=Chandra :: Photo Album :: IGR J11014-6103 :: June 28, 2012

}}

{{Cite journal|last1=Pavan |first1=L.

|display-authors=etal

|year=2015

|title=A closer view of the IGR J11014-6103 outflows

|journal=Astronomy & Astrophysics

|volume=591

|pages=A91

|arxiv=1511.01944

|bibcode=2016A&A...591A..91P

|doi=10.1051/0004-6361/201527703

|s2cid=59522014

}} Initially, this pulsar was presumed to be rapidly spinning, but later measurements indicate the spin rate is only 15.9 Hz.

{{Cite journal

|last1=Pavan |first1=L.

|display-authors=etal

|year=2014

|title=The long helical jet of the Lighthouse nebula, IGR J11014-6103

|url=http://www.aanda.org/articles/aa/pdf/2014/02/aa22588-13.pdf

|journal=Astronomy & Astrophysics

|volume=562 |issue=562

|pages=A122

|arxiv=1309.6792

|bibcode=2014A&A...562A.122P

|doi=10.1051/0004-6361/201322588

|s2cid=118845324

}} Long helical jet of Lighthouse nebula page 7

{{Cite journal

|last1=Halpern |first1=J. P.

|display-authors=etal

|year=2014

|title=Discovery of X-ray Pulsations from the INTEGRAL Source IGR J11014-6103

|journal=The Astrophysical Journal

|volume=795 |issue=2 |pages=L27

|arxiv=1410.2332

|bibcode=2014ApJ...795L..27H

|doi=10.1088/2041-8205/795/2/L27

|s2cid=118637856

}} Such a slow spin rate and lack of accretion material suggest the jet is neither rotation nor accretion powered, though it appears aligned with the pulsar rotation axis and perpendicular to the pulsar's true motion.

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File:Opo0113i.jpg|Illustration of the dynamics of a proplyd, including a jet

File:NGC 5128.jpg|Centaurus A in x-rays showing the relativistic jet

File:Onde-radioM87.jpg|The M87 jet seen by the Very Large Array in radio frequency (the viewing field is larger and rotated with respect to the above image.)

File:HST-3C66B-jet-O5BQ06010.gif|Hubble Legacy Archive Near-UV image of the relativistic jet in 3C 66B

File:hs-2015-19-a-small web.jpg|Galaxy NGC 3862, an extragalactic jet of material moving at nearly the speed of light can be seen at the three o'clock position.

File:Hubble Sees the Force Awakening in a Newborn Star (23807356641).jpg|Some of the jets in HH 24-26, which contains the highest concentration of jets known anywhere in the sky

• disk wind slower wide-angle outflow, often occurring together with a jet
• Accretion disk
• Bipolar outflow
• Blandford–Znajek process
• Herbig–Haro object
• Penrose process
• CGCG 049-033, elliptical galaxy located 600 million light-years from Earth, known for having the longest galactic jet discovered
• Gamma-ray burst
• Solar jet

{{reflist}}

• [http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/990923a.html NASA – Ask an Astrophysicist: Black Hole Bipolar Jets]
• [http://www.space.com/scienceastronomy/blackhole_jets_040817.html SPACE.com – Twisted Physics: How Black Holes Spout Off]
• {{Cite arXiv |eprint=astro-ph/0107228v1 |last1=Blandford |first1=Roger |title=Compact Objects and Accretion Disks |last2=Agol |first2=Eric |last3=Broderick |first3=Avery |last4=Heyl |first4=Jeremy |last5=Koopmans |first5=Leon |last6=Lee |first6=Hee-Won |year=2001}}
• [https://www.youtube.com/watch?v=nf7W-WfKxLM Hubble Video Shows Shock Collision inside Black Hole Jet] ([http://www.nasa.gov/feature/goddard/hubble-video-shows-shock-collision-inside-black-hole-jet Article])

Category:Space plasmas

Category:Black holes

Jet, Astrophysical

Category:Concepts in stellar astronomy