Messier Index/M90

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Messier 90a
Messier 90.jpg
Messier 90
Observation data (w:J2000 epoch)
Constellation Virgo[1]
Right ascension 12h 36m 49.8s[2]
Declination +13° 09′ 46″[2]
Type SAB(rs)ab[2], w:LINER[2], Sy[2]
Apparent magnitude (V) 10.26[2]
Other designations
NGC 4569,[2] UGC 7786,[2] PGC 42089,[2] Arp 76[2]

Messier 90 (also known as M90 and NGC 4569) is a w:spiral galaxy about 60 million w:light-years away in the w:constellation Virgo. It was discovered by w:Charles Messier in w:1781.[3]

Membership of the Virgo Cluster

Messier 90 is a member of the w:Virgo Cluster.[4] The galaxy is located approximately 1°.5 away from the subgroup centered on w:Messier 87.[5] As a consequence of the galaxy's interaction with the w:intracluster medium in the Virgo Cluster, the galaxy has lost much of its w:interstellar medium. As a result of this process, which is referred to as ram pressure stripping, the galaxy's interstellar medium and star formation regions appear truncated compared to similar galaxies outside the Virgo Cluster.[6]

Star formation activity

As stated above, the w:star formation in Messier 90 appears truncated. Consequently, the galaxy's spiral arms appear to be smooth and featureless, rather than knotted like galaxies with extended star formation.[6] However, the center of Messier 90 appears to be a site of significant star formation activity. Multiple w:supernovae in the nucleus have produced 'superwinds' that are blowing the galaxy's interstellar medium outward into the intracluster medium.[7]

Blueshift

The w:spectrum of Messier 90 is w:blueshifted, which indicates that it is moving towards the Earth.[2] In contrast, the spectra of most other galaxies are w:redshifted. The blueshift was originally used to argue that Messier 90 was actually an object in the foreground of the Virgo Cluster. However, since the phenomenon was limited mostly to galaxies in the same part of the sky as the Virgo Cluster, it appeared that this inference based on the blueshift was incorrect. Instead, the blueshift is thought to be evidence for the large range in velocities of objects within the Virgo Cluster itself.[5]

Distance measurements

Low levels of w:H I gas prevents using the w:Tully-Fisher relation to estimate the distance to Messier 90.[7]

Companion galaxies

Messier 90 has a w:satellite galaxy (w:IC 3583) which is an w:irregular galaxy[citation needed].

External links

Notes

^a Tschöke et al. 2001 uses a w:Hubble constant of 75 (km/s)/Mpc to estimate a distance of 16.8 Mpc to NGC 4569. Adjusting for the 2006 value of 70+2.4−3.2 (km/s)/Mpc we get a distance of 18.0+0.9−0.6 Mpc.

References

  1. R. W. Sinnott, editor (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation and Cambridge University Press. ISBN 0-933-34651-4. 
  2. a b c d e f g h i j k "NASA/IPAC Extragalactic Database". Results for NGC 205. http://nedwww.ipac.caltech.edu/. Retrieved 2006-02-01. 
  3. K. G. Jones (1991). Messier's Nebulae and Star Clusters (2nd ed.). Cambridge: Cambridge University Press. ISBN 0-521-37079-5. 
  4. B. Binggeli, A. Sandage, G. A. Tammann (1985). "Studies of the Virgo Cluster. II - A catalog of 2096 galaxies in the Virgo Cluster area". Astronomical Journal 90: 1681–1759. doi:10.1086/113874. http://adsabs.harvard.edu/abs/1985AJ.....90.1681B. 
  5. a b A. Sandage, J. Bedke (1994). Carnegie Atlas of Galaxies. Washington, D.C.: Carnegie Institution of Washington. ISBN 0-87279-667-1. 
  6. a b R. A. Koopmann, J. D. P. Kenney (2004). "Hα Morphologies and Environmental Effects in Virgo Cluster Spiral Galaxies". Astrophysical Journal 613: 866–885. doi:10.1086/423191. http://adsabs.harvard.edu/abs/2004ApJ...613..866K. 
  7. a b D. Tschöke, D. J. Bomans, G. Hensler, N. Junkes (2001). "Hot halo gas in the Virgo cluster galaxy NGC 4569". Astronomy and Astrophysics 380: 40–54. doi:10.1051/0004-6361:20011354. http://adsabs.harvard.edu/abs/2001A&A...380...40T.