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NGC 6185

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NGC 6185
PanSTARRS DR1 image of NGC 6185
Observation data (J2000 epoch)
ConstellationHercules
Right ascension16h 33m 17.83s
Declination+35° 20′ 32.43"
Redshift0.034304
Heliocentric radial velocity10108
Distance492.9 mly (152.04 mpc)
Group or clusterAbell 2199
Apparent magnitude (B)14.5
Characteristics
TypeSa
Mass295.1 billion M
Size239,400 ly (73,410 pc)
Apparent size (V)1.2' x 0.9'
Other designations
UGC 10444, KUG 1631+354, CGCG 196-077

NGC 6185, also called UGC 10444, is a LINER and spiral galaxy of morphological type Sa.[1] It is at redshift z = 0.034304, equivalent to 152 million parsecs (496 million light-years) away, in the constellation of Hercules, and has an apparent B magnitude of 14.5.[1][2] The galaxy was discovered in April 1827 by British astronomer John Herschel.[3]

Physical properties

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NGC 6185 is a massive spiral Sa galaxy in the galaxy cluster Abell 2199. It is 239,000 light-years (73,000 parsecs) across based on an angular diameter of 1.2 arcmin and a distance of 152 million parsecs (496 million light-years) away.[2] It has a stellar mass of 295.1×109 M and is believed to be a starburst galaxy.[4]

It has an active galactic nucleus (AGN) that is also classified as a quasar[1] and is estimated to be extremely bright with a luminosity of 131.5×109 L.[4] The active galactic nucleus of NGC 6185 is powered by a 600-million-M black hole accreting matter that is ejected far beyond the physical galaxy, forming its immense radio lobes.[4] The central black hole mass is high; however, it is expected for giant radio galaxies (GRGs) and is comparable to similar spiral-hosted radio galaxies such as J2345-0449.[4] It is possible that the active galactic nucleus is inactive and the radio structure is a remnant.[4]

In 2016, an ultraluminous X-ray source was discovered in NGC 6185. It was designated CXOU J163317.7+352018 and has an estimated luminosity of 57.9 million L.[5]

LoTSS image of the radio lobes of NGC 6185

In 2022, it was found in the LOFAR Two-metre Sky Survey for giants (LoTSS) that NGC 6185 generated radio lobes spanning ~2.54 megaparsecs, making it the largest known spiral galaxy-hosted radio galaxy. It greatly surpasses the previous largest spiral radio galaxy, J2345-0449, which has an extent of ~1.63 megaparsecs.[4][6] The radio structure is a Fanaroff-Riley class II radio galaxy which are edge-brightened and far more luminous than their counterpart, and it is also a double lobed radio galaxy, so it is technically classified as a spiral DRAGN.[4] The total exact length of the radio structure is 2.544 million parsecs (8.30×10^6 ly), comparable to the Local Group and other small galaxy clusters.[6] This estimate is based on an angular diameter of 60 arcmin, which is the second-largest of any GRG.[6]

See also

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References

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  1. ^ a b c "NGC 6185". SIMBAD. Retrieved 2025-11-29.
  2. ^ a b "NED results for NGC 6185". NASA/IPAC Extragalactic Database. Retrieved 2025-11-29.
  3. ^ "NGC 6150-6199". New General Catalog Objects. Retrieved 2025-11-29.
  4. ^ a b c d e f g Oei, Martijn (2022). "An intergalactic medium temperature from a giant radio galaxy". Monthly Notices of the Royal Astronomical Society. 518: 240–256. arXiv:2210.10156. doi:10.1093/mnras/stac2948.
  5. ^ Gong, Hang (2016). "An Extreme Luminous X-ray Source Catalog Based on Chandra ACIS Observations". The Astrophysical Journal Supplement Series. 222 (1): 12. Bibcode:2016ApJS..222...12G. doi:10.3847/0067-0049/222/1/12.
  6. ^ a b c Oei, Martijn (2022). "Measuring the giant radio galaxy length distribution with the LoTSS". Astronomy & Astrophysics. 672: A163. arXiv:2210.10234. doi:10.1051/0004-6361/202243572.