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))
Two supernovae have been observed in M106: SN 1981K (type II, mag. 17),[9] and SN 2014bc (type II, mag. 14.8).[10][11]
Characteristics
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 4×107M☉.[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)×107M☉.[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.
^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. S2CID89905.
External links
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