# 3C 343

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Quasar located in the constellation Draco

3C 343 SDSS image of 3C 343. Observation data (J2000.0 epoch) Constellation Draco Right ascension 16h 34m 33.80s[1] Declination +62° 45′ 35.89″[1] Redshift 0.988000[1] Heliocentric radial velocity 296,195 km/s[1] Distance 7.880 Gly Apparent magnitude (B) 21.06 Characteristics Type HEG, CSS[1] Other designations 4C +62.26, LEDA 2817689, NVSS J163433+624535, 6C B163400.8+625137, DA 416, NRAO 0509, CoNFIG 255[1]

**3C 343** is a [quasar](/source/Quasar)[2] located in the constellation of [Draco](/source/Draco_(constellation)). The [redshift](/source/Redshift) of the object is (z) 0.988[1] and it was first recorded in the [Third Cambridge Catalogue of Radio Sources](/source/Third_Cambridge_Catalogue_of_Radio_Sources) survey in 1962.[3] It is a [Seyfert type 2 galaxy](/source/Seyfert_galaxy)[4] and such contains a compact steep [spectrum](/source/Spectrum) source that is classified as double.[5][6][7]

## Description

3C 343 is classified as a young radio-loud [active galaxy](/source/Active_galactic_nucleus) with a radio power of 27.7 [GHz](/source/Hertz).[8] It contains a compact source described as a single component that is around 200 [milliseconds](/source/Millisecond) in [diameter](/source/Diameter).[5] [Polarimetric](/source/Polarimetry) observations made with the [Very Long Baseline Array](/source/Very_Long_Baseline_Array) (VLBA) reveal two components that are surrounded by weak [radio emission](/source/Radio_wave). Both of these components are shown to have a steep [radio spectrum](/source/Radio_spectrum) between the frequencies of 4.8 and 8.4 GHz.[9]

Observations with European [Very Long Baseline Interferometry](/source/Very-long-baseline_interferometry) (VLBI) at 18 [centimeters](/source/Centimetre) showed the source has several emission ridges distributed across multiple [position angles](/source/Position_angle), while newer VLBI observations described the source as elongated from north to west.[10][11] A complex structure is found inside a core component by VLBI.[12] There is a [radio jet](/source/Astrophysical_jet) present in 3C 343, having a knotty appearance and deflated through collisions with [interstellar medium](/source/Interstellar_medium).[6] This jet is estimated to have a linear size of 1.45 [kiloparsecs](/source/Parsec).[8]

A new component was discovered in 3C 343 via an 8.4 GHz radio image. This component is found in an eastern direction from the first component and has an estimated [flux](/source/Flux) [density](/source/Density) of 7.7 [mJy](/source/Jansky). It is noted to have a radio spectrum that is inverted, making it possible this is the radio core. Further evidence also revealed the component is situated on the jet's curved [trajectory](/source/Trajectory) path. Polarization is found in 3C 343, with the [percentage](/source/Percentage) of it being around 0.96%.[9] It is noted to be variable, increasing rapidly though [wavelength](/source/Wavelength) observations.[13] A [supermassive black hole](/source/Supermassive_black_hole) mass of 7.5 M☉ has been found for the quasar.[14]

## References

1. ^ [***a***](#cite_ref-ned_1-0) [***b***](#cite_ref-ned_1-1) [***c***](#cite_ref-ned_1-2) [***d***](#cite_ref-ned_1-3) [***e***](#cite_ref-ned_1-4) [***f***](#cite_ref-ned_1-5) [***g***](#cite_ref-ned_1-6) ["NED Search results for 3C 343"](https://ned.ipac.caltech.edu/byname?objname=3C+343&hconst=67.8&omegam=0.308&omegav=0.692&wmap=4&corr_z=1). *NASA/IPAC Extragalactic Database*. Retrieved 2025-09-28.

1. **[^](#cite_ref-2)** Spencer, R.E.; McDowell, J.C.; Charlesworth, M.; Fanti, C.; Parma, P.; Peacock, J.A. (October 1989). ["MERLIN and VLA observations of compact steep-spectrum radio sources"](https://web.archive.org/web/20240626141627/https://ui.adsabs.harvard.edu/abs/1989MNRAS.240..657S/abstract). *Monthly Notices of the Royal Astronomical Society*. **240** (3): 657–687. [doi](/source/Doi_(identifier)):[10.1093/mnras/240.3.657](https://doi.org/10.1093%2Fmnras%2F240.3.657). [ISSN](/source/ISSN_(identifier)) [0035-8711](https://search.worldcat.org/issn/0035-8711). Archived from [the original](https://articles.adsabs.harvard.edu/pdf/1989MNRAS.240..657S) on 2024-06-26.

1. **[^](#cite_ref-3)** S., Bennett, A. (1962). ["The revised 3C catalogue of radio sources"](https://web.archive.org/web/20240413093523/https://ui.adsabs.harvard.edu/abs/1962MmRAS..68..163B/abstract). *Memoirs of the Royal Astronomical Society*. **68**: 163. [Bibcode](/source/Bibcode_(identifier)):[1962MmRAS..68..163B](https://ui.adsabs.harvard.edu/abs/1962MmRAS..68..163B). Archived from [the original](https://ui.adsabs.harvard.edu/abs/1962MmRAS..68..163B/abstract) on 2024-04-13.{{[cite journal](https://en.wikipedia.org/wiki/Template:Cite_journal)}}: CS1 maint: multiple names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_multiple_names:_authors_list))

1. **[^](#cite_ref-4)** Aldcroft, Thomas L.; Bechtold, Jill; Elvis, Martin (July 1994). ["MG II absorption in a sample of 56 steep-spectrum quasars"](https://web.archive.org/web/20240706052001/https://ui.adsabs.harvard.edu/abs/1994ApJS...93....1A/abstract). *The Astrophysical Journal Supplement Series*. **93**: 1. [Bibcode](/source/Bibcode_(identifier)):[1994ApJS...93....1A](https://ui.adsabs.harvard.edu/abs/1994ApJS...93....1A). [doi](/source/Doi_(identifier)):[10.1086/192044](https://doi.org/10.1086%2F192044). [ISSN](/source/ISSN_(identifier)) [0067-0049](https://search.worldcat.org/issn/0067-0049). Archived from [the original](https://ui.adsabs.harvard.edu/abs/1994ApJS...93....1A/abstract) on 2024-07-06.

1. ^ [***a***](#cite_ref-:0_5-0) [***b***](#cite_ref-:0_5-1) Pearson, T. J.; Readhead, A. C. S. (May 1988). ["The milliarcsecond structure of a complete sample of radio sources. II - First-epoch maps at 5 GHz"](https://web.archive.org/web/20221107063549/https://ui.adsabs.harvard.edu/abs/1988ApJ...328..114P/abstract). *The Astrophysical Journal*. **328**: 114. [Bibcode](/source/Bibcode_(identifier)):[1988ApJ...328..114P](https://ui.adsabs.harvard.edu/abs/1988ApJ...328..114P). [doi](/source/Doi_(identifier)):[10.1086/166274](https://doi.org/10.1086%2F166274). [ISSN](/source/ISSN_(identifier)) [0004-637X](https://search.worldcat.org/issn/0004-637X). Archived from [the original](https://ui.adsabs.harvard.edu/abs/1988ApJ...328..114P/abstract) on 2022-11-07.

1. ^ [***a***](#cite_ref-:1_6-0) [***b***](#cite_ref-:1_6-1) N., Ren-Dong; T., Schilizzi, R.; C., Fanti; R., Fanti; van Breugel, W. J. M.; W., Muxlow, T. (1988). ["The radio structure of the compact steep spectrum sources 3C 119, 3C 287 and 3C 343"](https://web.archive.org/web/20241110211100/https://ui.adsabs.harvard.edu/abs/1988IAUS..129..119R/abstract). *The Impact of VLBI on Astrophysics and Geophysics*. **129**. [ISSN](/source/ISSN_(identifier)) [1743-9221](https://search.worldcat.org/issn/1743-9221). Archived from [the original](https://ui.adsabs.harvard.edu/scan/manifest/1988IAUS..129..119R) on 2024-11-10.{{[cite journal](https://en.wikipedia.org/wiki/Template:Cite_journal)}}: CS1 maint: multiple names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_multiple_names:_authors_list))

1. **[^](#cite_ref-7)** Moffet, AT (1965). ["3C 343, a Double Radio Source with Very Wide Component Separation"](https://ui.adsabs.harvard.edu/scan/manifest/1965ApJ...141.1580M). *American Astronomical Society*.

1. ^ [***a***](#cite_ref-:2_8-0) [***b***](#cite_ref-:2_8-1) Kawakatu, Nozomu; Nagao, Tohru; Woo, Jong-Hak (2009-03-10). "Exploring the Disk-Jet Connection From the Properties of Narrow-Line Regions in Powerful Young Radio-Loud Active Galactic Nuceli". *The Astrophysical Journal*. **693** (2): 1686–1695. [arXiv](/source/ArXiv_(identifier)):[0812.1329](https://arxiv.org/abs/0812.1329). [Bibcode](/source/Bibcode_(identifier)):[2009ApJ...693.1686K](https://ui.adsabs.harvard.edu/abs/2009ApJ...693.1686K). [doi](/source/Doi_(identifier)):[10.1088/0004-637X/693/2/1686](https://doi.org/10.1088%2F0004-637X%2F693%2F2%2F1686). [ISSN](/source/ISSN_(identifier)) [0004-637X](https://search.worldcat.org/issn/0004-637X).

1. ^ [***a***](#cite_ref-:3_9-0) [***b***](#cite_ref-:3_9-1) Mantovani, F.; Rossetti, A.; Junor, W.; Saikia, D. J.; Salter, C. J. (2010-07-01). ["Radio polarimetry of 3C 119, 3C 318, and 3C 343 at milliarcsecond resolution"](https://www.aanda.org/articles/aa/abs/2010/10/aa14400-10/aa14400-10.html). *Astronomy & Astrophysics*. **518**: A33. [arXiv](/source/ArXiv_(identifier)):[1005.2950](https://arxiv.org/abs/1005.2950). [Bibcode](/source/Bibcode_(identifier)):[2010A&A...518A..33M](https://ui.adsabs.harvard.edu/abs/2010A&A...518A..33M). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201014400](https://doi.org/10.1051%2F0004-6361%2F201014400). [ISSN](/source/ISSN_(identifier)) [0004-6361](https://search.worldcat.org/issn/0004-6361).

1. **[^](#cite_ref-10)** C., Fanti; R., Fanti; P., Parma; T., Schilizzi, R.; van Breugel, W. J. M. (February 1985). ["Compact steep spectrum 3 CR radio sources. VLBI observations at 18 cm"](https://web.archive.org/web/20240327105002/https://ui.adsabs.harvard.edu/abs/1985A&A...143..292F/abstract). *Astronomy and Astrophysics*. **143**: 292. [Bibcode](/source/Bibcode_(identifier)):[1985A&A...143..292F](https://ui.adsabs.harvard.edu/abs/1985A&A...143..292F). [ISSN](/source/ISSN_(identifier)) [0004-6361](https://search.worldcat.org/issn/0004-6361). Archived from [the original](https://articles.adsabs.harvard.edu/pdf/1985A%26A...143..292F) on 2024-03-27.{{[cite journal](https://en.wikipedia.org/wiki/Template:Cite_journal)}}: CS1 maint: multiple names: authors list ([link](https://en.wikipedia.org/wiki/Category:CS1_maint:_multiple_names:_authors_list))

1. **[^](#cite_ref-11)** Dallacasa, D; Orienti, M; Fanti, C; Fanti, R (2021-04-13). ["VLBI images at 327 MHz of compact steep spectrum and GHz-peaked spectrum sources from the 3C and PW samples"](https://doi.org/10.1093%2Fmnras%2Fstab1014). *Monthly Notices of the Royal Astronomical Society*. **504** (2): 2312–2324. [arXiv](/source/ArXiv_(identifier)):[2104.12804](https://arxiv.org/abs/2104.12804). [doi](/source/Doi_(identifier)):[10.1093/mnras/stab1014](https://doi.org/10.1093%2Fmnras%2Fstab1014). [ISSN](/source/ISSN_(identifier)) [0035-8711](https://search.worldcat.org/issn/0035-8711).

1. **[^](#cite_ref-12)** Pearson, T. J.; Readhead, A. C. S.; Perley, R. A. (May 1985). ["Compact radio sources in the 3C catalog"](https://web.archive.org/web/20240609160637/https://ui.adsabs.harvard.edu/abs/1985AJ.....90..738P/abstract). *The Astronomical Journal*. **90**: 738. [Bibcode](/source/Bibcode_(identifier)):[1985AJ.....90..738P](https://ui.adsabs.harvard.edu/abs/1985AJ.....90..738P). [doi](/source/Doi_(identifier)):[10.1086/113782](https://doi.org/10.1086%2F113782). [ISSN](/source/ISSN_(identifier)) [0004-6256](https://search.worldcat.org/issn/0004-6256). Archived from [the original](https://articles.adsabs.harvard.edu/pdf/1985AJ.....90..738P) on 2024-06-09.

1. **[^](#cite_ref-13)** van Breugel, W.; Miley, G.; Heckman, T. (January 1984). ["Studies of kiloparsec-scale, steep-spectrum radio cores. I VLA maps"](https://web.archive.org/web/20240609175842/https://ui.adsabs.harvard.edu/abs/1984AJ.....89....5V/abstract). *The Astronomical Journal*. **89**: 5. [Bibcode](/source/Bibcode_(identifier)):[1984AJ.....89....5V](https://ui.adsabs.harvard.edu/abs/1984AJ.....89....5V). [doi](/source/Doi_(identifier)):[10.1086/113480](https://doi.org/10.1086%2F113480). [ISSN](/source/ISSN_(identifier)) [0004-6256](https://search.worldcat.org/issn/0004-6256). Archived from [the original](https://articles.adsabs.harvard.edu/pdf/1984AJ.....89....5V) on 2024-06-09.

1. **[^](#cite_ref-14)** Wu, Qingwen (2009-05-22), "The black hole mass, Eddington ratio and *M* BH-σ[O III]relation in young radio galaxies", *Monthly Notices of the Royal Astronomical Society*, **398** (4): 1905–1914, [arXiv](/source/ArXiv_(identifier)):[0905.3663](https://arxiv.org/abs/0905.3663), [Bibcode](/source/Bibcode_(identifier)):[2009MNRAS.398.1905W](https://ui.adsabs.harvard.edu/abs/2009MNRAS.398.1905W), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2009.15127.x](https://doi.org/10.1111%2Fj.1365-2966.2009.15127.x)

## External links

- 3C 343 on [WikiSky](/source/WikiSky): [DSS2](http://www.wikisky.org/?object=3C+343&img_source=DSS2), [SDSS](http://www.wikisky.org/?object=3C+343&img_source=SDSS), [GALEX](http://www.wikisky.org/?object=3C+343&img_source=GALEX), [IRAS](http://www.wikisky.org/?object=3C+343&img_source=IRAS), [Hydrogen α](http://www.wikisky.org/?object=3C+343&img_source=HALPHA), [X-Ray](http://www.wikisky.org/?object=3C+343&img_source=RASS), [Astrophoto](http://www.wikisky.org/?object=3C+343&img_source=IMG_all), [Sky Map](http://www.wikisky.org/?object=3C+343), [Articles and images](http://www.wikisky.org/starview?object=3C+343)

- [3C 343 on SIMBAD](http://simbad.u-strasbg.fr/simbad/sim-id?bibyear1=1850&bibyear2=%24currentYear&submit=Display&Ident=%40375002&Name=ICRF+J163433.8%2B624535&bibdisplay=refsum&bibyear1=1850&bibyear2=%24currentYear#lab_bib)

v t e Constellation of Draco List of stars in Draco Draco in Chinese astronomy Stars Bayer α (Thuban) β (Rastaban) γ (Eltanin) δ (Altais) ε (Tyl) ζ (Aldhibah) η (Athebyne) θ ι (Edasich) κ λ (Giausar) μ (Alrakis) ν (Kuma) ξ (Grumium) ο π ρ σ (Alsafi) τ υ φ χ ψ1 (Dziban) ψ2 ω Flamsteed 4 6 7 (Tianyi) 8 (Taiyi) 10 (i) 15 (A) 18 (g) 19 (h) 26 36 39 (b) 42 (Fafnir) 45 (d) 50 59 64 (e) 68 Variable TW YY AG BY CL CM CX DO EK HP V581 HR 3751 4126 4934 5811 6237 6518 6618 (Alruba) 6817 7137 7783 HD 109246 (Funi) 101364 128717 147379 156279 158259 176693 191939 Other 2MASS 1237+6526 2MASS J17554042+6551277 G 240-72 GD 356 Gliese 420 Gliese 625 Gliese 687 GRW +70 8247 Kepler-4 Kepler-10 Kepler-12 Kepler-90 Kepler-296 KOI-256 LP 71-82 Qatar-1 SDSS J1240+6710 Struve 2398 TOI-1136 WD 1856+534 WISE 1647+5632 WISE 1841+7000 Exoplanets HD 139357 b HD 167042 b ι Dra b (Hypatia) Kepler-4b Kepler-10b c Kepler-12b Kepler-90e f g h i Kepler-296b c d e f TOI-1452 b TrES-2b Star clusters LAMOST 1 Nebulae Cat's Eye Nebula NGC 6742 Galaxies NGC 3147 3197 3735 4121 4125 4221 4236 4319 4331 4332 4363 4441 4513 4545 4589 5678 5777 5866 5866B 5879 5905 5907 5949 5963 5965 5982 5985 6090 6248 6285 6286 6338 6340 6365 6373 6394 6412 6503 6505 6566 6621 6622 6670 6676 6786 6789 Other 1ES 1927+654 1ES 1959+650 3C 249.1 3C 305 3C 319 3C 343 3C 343.1 3C 351 3C 356 3C 371 3C 380 3C 390.3 3C 401 4C +72.26 4C 73.08 8C 1241+735 Abell 2218 BCG Bean galaxy Beaver galaxy BZQ J1727+5510 Draco Dwarf Draco II GB 1508+5714 Goldfish galaxy H1821+643 HFLS3 IERS B1946+708 IRAS F17179+5444 IRAS 18580+6527 J120011.1+680924.8 KKR 25 Markarian 817 Markarian 876 Original TRG PGC 39058 Porphyrion QSO B1823+568 RGZ J172749.5+534647 S5 1803+784 S5 2007+777 SDSS J1715+6008 Tadpole Galaxy UGC 9391 UGC 9405 UGC 11241 UGC 11411 WISEA J145223.62+611707.5 WN B1851+5707 Galaxy clusters Abell 2218 CL1358+62 Draco Supercluster NGC 5866 Group Astronomical events SN 2003jb SN 2005B SN 2016aps Swift J1644+57 Category

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Adapted from the Wikipedia article [3C 343](https://en.wikipedia.org/wiki/3C_343) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/3C_343?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.