Messier 106

Coordinates: Sky map 12h 18m 57.5s, +47° 18′ 14″
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Messier 106
Messier 106 visible and infrared composite.jpg
M106 and its anomalous arms. Composite of IR (red) and optical light (Credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), and R. Gendler (for the Hubble Heritage Team))
Observation data (J2000 epoch)
ConstellationCanes Venatici
Right ascension12h 18m 57.5s[1]
Declination+47° 18′ 14″[1]
Redshift448 ± 3 km/s[1]
Distance23.7 ± 1.5 Mly (7 ± 0.5 Mpc)[2][3]
Apparent magnitude (V)8.4[1]
Size135,000 ly (in diameter)[4]
Apparent size (V)18′.6 × 7′.2[1]
Notable featuresMegamaser galaxy,[5] Seyfert II galaxy.[6]
Other designations
M 106, NGC 4258, UGC 7353, PGC 39600.[1][7]

Messier 106 (also known as NGC 4258) is an intermediate spiral galaxy in the constellation Canes Venatici. It was discovered by Pierre Méchain in 1781. M106 is at a distance of about 22 to 25 million light-years away from Earth. M106 contains an active nucleus classified as a Type 2 Seyfert, and the presence of a central supermassive black hole has been demonstrated from radio-wavelength observations of the rotation of a disk of molecular gas orbiting within the inner light-year around the black hole.[8] NGC 4217 is a possible companion galaxy of Messier 106.[7]

Two supernovae have been observed in M106: SN 1981K (type II, mag. 17),[9] and SN 2014bc (type II, mag. 14.8).[10][11]


M106 has a water vapor megamaser (the equivalent of a laser operating in microwave instead of visible light and on a galactic scale) that is seen by the 22-GHz line of ortho-H2O that evidences dense and warm molecular gas. Water masers are useful for observing nuclear accretion disks in active galaxies. The water masers in M106 enabled the first case of a direct measurement of the distance to a galaxy, thereby providing an independent anchor for the cosmic distance ladder.[12][13] M106 has a slightly warped, thin, almost edge-on Keplerian disc which is on a subparsec scale. It surrounds a central area with mass 4×107 M.[14]

It is one of the largest and brightest nearby galaxies, similar in size and luminosity to the Andromeda Galaxy.[15] The supermassive black hole at the core has a mass of (3.9±0.1)×107 M.[16]

M106 has also played an important role in calibrating the cosmic distance ladder. Before, Cepheid variables from other galaxies could not be used to measure distances since they cover ranges of metallicities different from the Milky Way's. M106 contains Cepheid variables similar to both the metallicities of the Milky Way and other galaxies' Cepheids. By measuring the distance of the Cepheids with metallicities similar to our galaxy, astronomers are able to recalibrate the other Cepheids with different metallicities, a key fundamental step in improving quantification of distances to other galaxies in the universe.[3]

Composite image features X-rays from Chandra (blue), radio waves from the VLA (purple), optical data from Hubble (yellow and blue), and infrared with Spitzer (red). Two anomalous arms, which aren't visible at optical wavelengths, appear as purple and blue emissions.

See also[edit]


  1. ^ a b c d e f g "NASA/IPAC Extragalactic Database". Results for Messier 106. Retrieved 7 December 2006.
  2. ^ Tonry, J. L.; et al. (2001). "The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances". Astrophysical Journal. 546 (2): 681–693. arXiv:astro-ph/0011223. Bibcode:2001ApJ...546..681T. doi:10.1086/318301. S2CID 17628238.
  3. ^ a b Macri, L. M.; et al. (2006). "A New Cepheid Distance to the Maser-Host Galaxy NGC 4258 and Its Implications for the Hubble Constant". Astrophysical Journal. 652 (2): 1133–1149. arXiv:astro-ph/0608211. Bibcode:2006ApJ...652.1133M. doi:10.1086/508530. S2CID 15728812.
  4. ^ freestarcharts
  5. ^ Bonanos, Alceste Z. (2006). "Eclipsing Binaries: Tools for Calibrating the Extragalactic Distance Scale". Proceedings of the International Astronomical Union. 2 (S240): 79–87. arXiv:astro-ph/0610923. Bibcode:2007IAUS..240...79B. doi:10.1017/S1743921307003845. S2CID 18827791.
  6. ^ Humphreys, E. M. L.; et al. (2004). "Improved Maser Distance to NGC 4258". Bulletin of the American Astronomical Society. 36: 1468. Bibcode:2004AAS...205.7301H.
  7. ^ a b "M 106". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 7 December 2006.
  8. ^ Miyoshi, Makoto; et al. (12 January 1995). "Evidence for a black hole from high rotation velocities in a sub-parsec region of NGC4258". Nature. 373 (6510): 127–129. Bibcode:1995Natur.373..127M. doi:10.1038/373127a0. S2CID 4336316.
  9. ^ Transient Name Server entry for SN 1981K. Retrieved 29 March 2023.
  10. ^ Transient Name Server entry for SN 2014bc. Retrieved 22 March 2023.
  11. ^ "KAIT Prediscovery Detection of PS1-14xz in NGC 4258 (Messier 106)". The Astronomer's Telegram. Retrieved 17 August 2015.
  12. ^ Herrnstein, J. R.; et al. (1999). "A geometric distance to the galaxy NGC 4258 from orbital motions in a nuclear gas disk". Nature. 400 (6744): 539–541. arXiv:astro-ph/9907013. Bibcode:1999Natur.400..539H. doi:10.1038/22972. S2CID 204995005.
  13. ^ de Grijs, Richard (2011). An Introduction to Distance Measurement in Astronomy. Chichester: John Wiley & Sons. p. 109. ISBN 978-0-470-51180-0.
  14. ^ Henkel, C.; et al. (2005). "New H2O masers in Seyfert and FIR bright galaxies". Astronomy and Astrophysics. 436 (1): 75–90. arXiv:astro-ph/0503070. Bibcode:2005A&A...436...75H. doi:10.1051/0004-6361:20042175. S2CID 117098659.
  15. ^ Karachentsev, Igor D.; Karachentseva, Valentina E.; Huchtmeier, Walter K.; Makarov, Dmitry I. (2003). "A Catalog of Neighboring Galaxies". The Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905.
  16. ^ Graham, Alister W. (November 2008). "Populating the Galaxy Velocity Dispersion – Supermassive Black Hole Mass Diagram: A Catalogue of (Mbh, σ) Values". Publications of the Astronomical Society of Australia. 25 (4): 167–175. arXiv:0807.2549. Bibcode:2008PASA...25..167G. doi:10.1071/AS08013. S2CID 89905.

External links[edit]