View source for 3C 273

{{Short description|Brightest quasar from Earth located in the constellation Virgo}}
{{Infobox quasar
 | name = [[Third Cambridge Catalogue of Radio Sources|3C]] 273
 | image = Best image of bright quasar 3C 273 (10953173335).jpg
 | caption= Quasar 3C 273 taken by [[Hubble Space Telescope|HST]]<ref>{{cite news|title=Best image of bright quasar 3C 273|url=http://www.spacetelescope.org/images/potw1346a/|access-date=20 November 2013|newspaper=ESA/Hubble Picture of the Week}}</ref>
 | epoch = [[J2000]]
 | ra = {{RA|12|29|06.7}}<ref name="ned">{{cite web | title=NASA/IPAC Extragalactic Database | work=Results for 3C 273 | url=http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=3C+273&extend=no | access-date=2006-10-26 }}</ref>
 | dec = {{DEC|+02|03|09}}<ref name="ned"/>
 | constellation name = [[Virgo (constellation)|Virgo]]
 | z = 0.158339 ± 0.000067<ref name="ned"/>
 | type = [[Blazar]]; Sy1<ref name="ned"/>
 | dist_ly = {{cvt|2.443|Gly|Mpc|0|lk=on}}<ref name=XJET>{{cite web
|date=2008-01-11 |title=3C 273 |publisher=XJET: X-Ray Emission from Extragalactic Radio Jets |url=http://hea-www.harvard.edu/XJET/source-d.cgi?3C_273 |access-date=2010-04-05}}</ref><ref name="Uchiyamaetal2006"/> (luminosity distance)<br>{{val|1.80|0.32|0.28|u=Gly|fmt=commas}}&nbsp;({{val|552|97|79|u=Mpc}})<ref name=Wang_et_al_2020>{{cite journal
| title=A parallax distance to 3C 273 through spectroastrometry and reverberation mapping | last1=Wang | first1=Jian-Min | last2=Songsheng | first2=Yu-Yang | last3=Li | first3=Yan-Rong | last4=Du | first4=Pu | last5=Zhang | first5=Zhi-Xiang | journal=Nature Astronomy | volume=4 | pages=517–525 | date=January 2020 | issue=5 | doi=10.1038/s41550-019-0979-5 | arxiv=1906.08417 | bibcode=2020NatAs...4..517W | s2cid=256707018 }}</ref> (parallax distance)
 | appmag_v = 12.9<ref name="ned"/>
 | size_v =
 | notes = optically brightest quasar, first spectrum of a quasar
 | names = [[Principal Galaxies Catalogue|PGC]] 41121<ref name="ned"/> and [[Hipparcos Catalogue|HIP]] 60936
| mass=886 ± 187 × 10<sup>6</sup>
| luminosity=10<sup>12</sup>
}}
'''3C 273''' is a [[quasar]] located at the center of a giant [[elliptical galaxy]] in the [[constellation]] of [[Virgo (constellation)|Virgo]]. It was the first quasar ever to be identified and is the visually brightest quasar in the sky as seen from Earth, with an [[apparent visual magnitude]] of 12.9.<ref name="ned"/> The derived distance to this object is {{convert|749|Mpc|e9ly|1|abbr=off|lk=on}}. The mass of its central [[supermassive black hole]] is approximately 886 million times the [[mass of the Sun]].

== Observation ==
3C 273 is visible from March to July in both the [[Northern Hemisphere|northern]] and [[Southern Hemisphere|southern]] hemispheres. Situated in the Virgo constellation, it is bright enough to be observed by eye with a {{convert|6|inch|adj=on}} [[amateur astronomy|amateur telescope]].<ref>{{citation|work=[[Astronomy (magazine)|Astronomy]]|title=Target acquired: Observe Quasar 3C 273|first=Richard |last=Talcott | date=November 17, 2023|url=https://www.astronomy.com/observing/hunting-quasar-3c-273/}}</ref> Due in part to its radio luminosity and its discovery as the first identified quasar, 3C 273's [[right ascension]] in the [[Fifth Fundamental Catalog]] (FK5) is used to standardize the positions of 23 extragalactic radio sources used to define the [[International Celestial Reference System]] (ICRS).<ref name="def_syst">{{cite web | url=http://hpiers.obspm.fr/icrs-pc/icrs/def_syst.html | title=Definition of ICRS Axes | author=International Earth Rotation & Reference Systems Service | access-date=11 January 2012}}</ref>

Given its distance from [[Earth]] and visual magnitude, 3C 273 is the most distant celestial object average amateur astronomers are likely to see through their telescopes.

==Properties==
[[Image:Quasar 3C 273.jpg|thumb|left|200px|3C 273 as imaged by the [[Hubble Space Telescope]]'s [[Advanced Camera for Surveys]]. Light from the bright quasar nucleus is blocked by a [[coronagraph]] so that the surrounding host galaxy can be more easily seen. Credit: [[NASA]]/[[ESA]]]]
This is the [[optic]]ally brightest quasar in the sky from Earth with an [[apparent visual magnitude]] of ~12.9, and one of the closest with a [[redshift]], ''z'', of 0.158.<ref name="Schmidt1963"/> A [[luminosity distance]] of D<sub>L</sub> = {{convert|749|Mpc|e9ly|1|abbr=off|lk=on}} may be calculated from ''z''.<ref name="Uchiyamaetal2006">{{cite journal | display-authors=6 | author=Uchiyama, Yasunobu | author2=Urry, C. Megan | author3=Cheung, C. C. | author4=Jester, Sebastian | author5=Van Duyne, Jeffrey | author6=Coppi, Paolo | author7=Sambruna, Rita M. | author8=Takahashi, Tadayuki | author9= Tavecchio, Fabrizio | author10=Maraschi, Laura | title=Shedding New Light on the 3C 273 Jet with the Spitzer Space Telescope | journal=The Astrophysical Journal | date=2006 | volume=648 | issue=2 | pages=910–921 | bibcode=2006ApJ...648..910U | doi=10.1086/505964|arxiv = astro-ph/0605530 | s2cid=119520309 }}</ref> Using [[stellar parallax|parallax]] methods with the [[Very Large Telescope]] [[Interferometry|interferometer]] yields a distance estimate of {{val|1.80|0.32|0.28|u=Gly|fmt=commas}}&nbsp;({{val|552|97|79|u=Mpc}}).<ref name=Wang_et_al_2020/>

It is one of the most luminous quasars known, with an [[absolute magnitude]] of −26.7,<ref name="3C 273 article">{{Cite journal|title=The Quasi-Stellar Radio Sources 3C 48 and 3C 273| bibcode=1964ApJ...140....1G| journal=The Astrophysical Journal|year=1964 |doi = 10.1086/147889 |last1=Greenstein |first1=Jesse L. |last2=Schmidt |first2=Maarten |volume=140 |page=1 |s2cid=123147304 |doi-access=free }}</ref> meaning that if it were only as distant as [[Pollux (star)|Pollux]] (~10 [[parsec]]s) it would [[Apparent magnitude|appear nearly as bright]] in the sky as the [[Sun]].<ref>{{cite web | title=Best image of bright quasar 3C 273 | website=esahubble.org | date=November 18, 2013 | url=https://esahubble.org/images/potw1346a/ | access-date=2023-02-25 }}</ref> Since the Sun's [[absolute magnitude]] is 4.83, it means that the quasar is over 4 trillion times more [[luminosity|luminous]] than [[Solar luminosity|the Sun]] at visible wavelengths.<ref>Per the formula for [[Magnitude_(astronomy)#Apparent_magnitude|comparing fluxes and magnitudes]]: <math>10^{(4.83+26.7)/2.5}=4.09*10^{12}</math>.</ref>

The [[luminosity]] of 3C 273 is variable at nearly every [[wavelength]] from [[radio wave]]s to [[gamma ray]]s on timescales of a few days to decades. [[Polarization (waves)|Polarization]] with coincident orientation has been observed with radio, [[infrared]], and optical light being emitted from a [[Astrophysical jet|large-scale jet]]; these emissions are therefore almost certainly [[synchrotron radiation|synchrotron]] in nature.<ref name="Uchiyamaetal2006"/> The radiation is created by a jet of charged particles moving at [[relativistic speed]]s. [[VLBI]] radio observations of 3C 273 have revealed [[proper motion]] of some of the radio emitting regions, further suggesting the presence of [[relativistic jets]] of material.<ref>{{Cite journal|doi=10.1038/290365a0|title=Superluminal expansion of quasar 3C273|date=1981|last1=Pearson|first1=T. J.|last2=Unwin|first2=S. C.|last3=Cohen|first3=M. H.|last4=Linfield|first4=R. P.|last5=Readhead|first5=A. C. S.|last6=Seielstad|first6=G. A.|last7=Simon|first7=R. S.|last8=Walker|first8=R. C.|journal=Nature|volume=290|issue=5805|pages=365|bibcode = 1981Natur.290..365P |s2cid=26508893 }}</ref><ref>{{Cite journal|doi=10.1038/354374a0|title=Large-scale superluminal motion in the quasar 3C273|date=1991|last1=Davis|first1=R. J.|last2=Unwin|first2=S. C.|last3=Muxlow|first3=T. W. B.|journal=Nature|volume=354|issue=6352|pages=374|bibcode = 1991Natur.354..374D |s2cid=4271003 }}</ref>

This is a prototype of an [[Active Galactic Nucleus]], demonstrating that the energy is being produced through [[Accretion (astrophysics)|accretion]] by a [[supermassive black hole]] (SMBH). No other astrophysical source can produce the observed energy.<ref name=Husemann_et_al_2019>{{cite journal | title=Jet-driven Galaxy-scale Gas Outflows in the Hyperluminous Quasar 3C 273 | last1=Husemann | first1=Bernd | last2=Bennert | first2=Vardha N. | last3=Jahnke | first3=Knud | last4=Davis | first4=Timothy A. | last5=Woo | first5=Jong-Hak | last6=Scharwächter | first6=Julia | last7=Schulze | first7=Andreas | last8=Gaspari | first8=Massimo  | last9=Zwaan | first9=Martin A. | journal=The Astrophysical Journal | volume=879 | issue=2 | id=75 | date=July 2019 | page=75 | doi=10.3847/1538-4357/ab24bc | arxiv=1905.10387 | bibcode=2019ApJ...879...75H | s2cid=166227892 | doi-access=free }}</ref> The mass of its central SMBH has been measured to be {{val|886|187}} million [[solar mass]]es through broad emission-line [[reverberation mapping]].<ref name="Petersonetal2004">{{cite journal | display-authors=6 | author=Peterson, B. M. | author2=Ferrarese, L. | author3=Gilbert, K. M. | author4=Kaspi, S. | author5=Malkan, M. A. | author6=Maoz, D. | author7=Merritt, D. | author7-link=David Merritt | author8=Netzer, H. | author9=Onken, C. A. | author10=Pogge, R. W. | author11=Vestergaard, M. | author12=Wandel, A. | title=Central Masses of AGNs. II. | journal=The Astrophysical Journal | date=2004 | volume=613 | issue=2 | pages=682–699 | doi=10.1086/423269| bibcode=2004ApJ...613..682P|arxiv = astro-ph/0407299 | s2cid=16308360 }}</ref>

===Large-scale jet===
The quasar has a large-scale visible [[astrophysical jet|jet]], which measures ~{{convert|200000|ly|kpc}} long, having an apparent size of 23″.<ref name="Uchiyamaetal2006"/> Such jets are believed to be created by the interaction of the central [[black hole]] and the [[accretion disk]]. In 1995, optical imaging of the jet using the [[Hubble Space Telescope]] revealed a structured [[Galaxy morphological classification|morphology]] evidenced by repeated bright knots interlaced by areas of weak emission.<ref name="Uchiyamaetal2006"/> The viewing angle of the jet is about 6° as seen from Earth. The jet was observed to abruptly change direction by an intrinsic angle of 2° in 2003, which is larger than the jet's intrinsic opening angle of 1.1°.<ref>{{cite journal | title=An Oversized Magnetic Sheath Wrapping around the Parsec-scale Jet in 3C 273 | last1=Lisakov | first1=M. M. | last2=Kravchenko | first2=E. V. | last3=Pushkarev | first3=A. B. | last4=Kovalev | first4=Y. Y. | last5=Savolainen | first5=T. K. | last6=Lister | first6=M. L. | journal=The Astrophysical Journal | volume=910 | issue=1 | id=35 | date=March 2021 | page=35 | doi=10.3847/1538-4357/abe1bd | arxiv=2102.04563 | bibcode=2021ApJ...910...35L | s2cid=231855529 | doi-access=free }}</ref> An expanding cocoon of heated gas is being generated by the jet, which may be impacting an inclined disk of gas within the central {{val|6|u=kpc|p=~&nbsp;}}.<ref name=Husemann_et_al_2019/>

===Host galaxy===
3C 273 lies at the center of a giant [[elliptical galaxy]] with an [[apparent magnitude]] of 16 and an apparent size of 29 [[arcseconds]]. The [[Galaxy morphological classification|morphological classification]] of the host galaxy is E4,<ref name="Bahcall97">{{cite journal | author=Bahcall, John N. | author2=Kirhakos, Sofia | author3=Saxe, David H. | author4=Schneider, Donald P. | title=Hubble Space Telescope Images of a Sample of 20 Nearby Luminous Quasars | journal=The Astrophysical Journal | date=1997 | volume=479 | issue=2 | pages=642–658 |arxiv=astro-ph/9611163 | bibcode=1997ApJ...479..642B | doi=10.1086/303926| s2cid=15318893 }}</ref> indicating a moderately flattened elliptical shape. The galaxy has an estimated mass of {{val|2|e=11|ul=solar mass|p=~&nbsp;}}.<ref>{{cite journal | title=Kinematics of the Broad-line Region of 3C 273 from a 10 yr Reverberation Mapping Campaign | last1=Zhang | first1=Zhi-Xiang | last2=Du | first2=Pu | last3=Smith | first3=Paul S. | last4=Zhao | first4=Yulin | last5=Hu | first5=Chen | last6=Xiao | first6=Ming | last7=Li | first7=Yan-Rong | last8=Huang | first8=Ying-Ke | last9=Wang | first9=Kai | last10=Bai | first10=Jin-Ming | last11=Ho | first11=Luis C. | last12=Wang | first12=Jian-Min | journal=The Astrophysical Journal | volume=876 | issue=1 | id=49 | date=May 2019 | page=49 | doi=10.3847/1538-4357/ab1099 | arxiv=1811.03812 | bibcode=2019ApJ...876...49Z | s2cid=119403004 | doi-access=free }}</ref>

==History==
The name signifies that it was the 273rd object (ordered by [[right ascension]]) of the Third [[University of Cambridge|Cambridge]] Catalog of Radio Sources ([[Third Cambridge Catalogue of Radio Sources|3C]]), published in 1959. After accurate positions were obtained using [[lunar occultation]] by [[Cyril Hazard]] at the [[Parkes Radio Telescope]],<ref name="HazardMackeyShimmins63">{{cite journal | author=Hazard, C. | author2=Mackey, M. B. | author3=Shimmins, A. J. | title=Investigation of the Radio Source 3C273 by the method of Lunar Occultations | journal=Nature | date=1963 | volume=197 | issue=4872 | pages=1037 | bibcode=1963Natur.197.1037H | doi=10.1038/1971037a0| s2cid=4270661 }}</ref> the radio source was quickly associated with an [[optical]] counterpart, an unresolved ''stellar object''. In 1963, [[Maarten Schmidt]]<ref name="Schmidt1963">{{cite journal | author=Schmidt, M.| title=3C 273 : A Star-Like Object with Large Red-Shift| journal=Nature| date=1963| volume=197| issue=4872| pages=1040| bibcode=1963Natur.197.1040S| doi=10.1038/1971040a0| doi-access=free}}</ref> and [[Bev Oke]]<ref name="Oke1963">{{cite journal| author=Oke, J. B.| title=Absolute Energy Distribution in the Optical Spectrum of 3C 273| journal=Nature| date=1963| volume=197| issue=4872| pages=1040–1041| bibcode=1963Natur.197.1040O| doi=10.1038/1971040b0| s2cid=4269940}}</ref> published a pair of papers in ''[[Nature (journal)|Nature]]'' reporting that 3C 273 has a substantial [[redshift]] of 0.158, placing it several billion [[light-year]]s away.

Prior to the discovery of 3C 273, several other radio sources had been associated with optical counterparts, the first being [[3C 48]]. Also, many [[Active Galactic Nucleus|active galaxies]] had been misidentified as [[variable star]]s, including the famous [[BL Lacertae|BL Lac]], [[W Comae Berenices|W Com]] and [[AU Canum Venaticorum|AU CVn]]. However, it was not understood what these objects were, since their spectra were unlike those of any known stars. Its spectrum did not resemble that of any normal stars with typical stellar elements. 3C 273 was the first object to be identified as a [[quasar]]—an extremely luminous object at an astronomical distance.

3C 273 is a radio-loud quasar, and was also one of the first extragalactic [[X-ray]] sources discovered in 1970.
However, even to this day, the process which gives rise to the X-ray emissions is controversial.<ref name="Uchiyamaetal2006"/>

==See also==
*[[List of quasars]]

==References==
{{reflist}}

== External links ==
* [http://isdc.unige.ch/3c273/ 3C 273's Database at the INTEGRAL Science Data Centre (ESA)]
* [http://www.perseus.gr/Astro-DSO-QSO-3C273.htm Detailed CCD image of 3C 273 based on 30 min total exposure]
* [http://astro.neutral.org/imagehtml/20050408_3c273.html Amateur 3C 273 Redshift Measurement]
* [http://www.nightskyinfo.com/archive/3c273_quasar NightSkyInfo.com – 3C 273]
* [http://www.sky-map.org/?object=3C%20273&zoom=12&img_source=SDSS  SKY-MAP.ORG SDSS image of 3C 273]
* [https://web.archive.org/web/20090123191313/http://www.aavso.org/vstar/vsots/spring05.shtml The Quasar 3C 273: Spring 2005 – Variable Star Of The Season AAVSO]
* {{WikiSky|z=12}}

{{Sky|12|29|06.7|+|02|03|09|2440000000}}
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{{DEFAULTSORT:3C 273}}
[[Category:Virgo (constellation)]]
[[Category:OVV quasars]]
[[Category:3C objects|273]]