NGC 4365
| NGC 4365 | |
|---|---|
 Hubble Space Telescope image of NGC 4365 | |
| Observation data (J2000 epoch) | |
| Constellation | Virgo |
| Right ascension | 12h 24m 28.228s[1] |
| Declination | +07° 19′ 03.07″[1] |
| Redshift | −0.00022±0.00009[2] |
| Heliocentric radial velocity | 1,221 km/s[3] |
| Distance | 74.4 Mly (22.80 Mpc)[3] |
| Apparent magnitude (B) | 11.5[4] |
| Characteristics | |
| Type | E3[5] |
| Other designations | |
| UGC 7488, MCG +01-32-048, PGC 40375[4] | |
NGC 4365 is a giant[6] elliptical galaxy[7] located in the constellation Virgo. It was discovered by German-English astronomer William Herschel on April 13, 1784.[8][9][10] The galaxy is located at an estimated distance of 74.4 million light-years (22.80 Mpc) from the Milky Way galaxy.[3]
Observations
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NGC 4365 is the central galaxy of the Virgo W' cloud, a sub-group of galaxies about 6 megaparsecs behind (further from us than) the Virgo Supercluster.[6] There is a stream of globular clusters connecting NGC 4365 to the neighboring compact lenticular galaxy NGC 4342. It appears that NGC 4365 is stripping globular clusters and stars from its smaller neighbor via tidal interaction.[6]
The morphological classification of NGC 4365 is E3, indicating a slightly flattened elliptical galaxy with an ellipticity of 0.26. It has a smooth luminosity profile with no indication of dust arms. There is a shallow cusp at the center.[5] The galaxy has a kinematically distinct core region that is rotating at right angles to the rest of the galaxy, which provides strong evidence for the theory that elliptical galaxies grow through mergers.[11] Most of the galaxy is rotating around the major axis with the peak velocity reaching around 50 km/s, whereas within 2″–3″ of the center the peak velocity is 80 km/s around the minor axis. This core region is more flattened than the galaxy as a whole,[5] forming a bar-like structure.[11]
The stellar populations of the galaxy suggest it underwent star formation at an early age, with the residual gas being exhausted about 12 billion years ago.[5] In contrast, many of the globular clusters of this galaxy appeared to be of intermediate age of 2–8 billion years old.[12] However, they may instead be of higher than expected metallicity.[8][10] The galaxy retains a triaxial structure that has remained largely unchanged for 12 billion years. Because supermassive black holes (SMBH) in the centers of galaxies tend to scatter stars into chaotic new orbits, the longevity of NGC 4365's triaxial structure and kinematically distinct stellar populations indicates that it cannot have an SMBH with a mass greater than 3×109 M☉. The M–sigma relation predicts a SMBH mass of 4×108 M☉ for NGC 4365.[13]
References
[edit]- ^ a b Skrutskie, Michael F.; et al. (1 February 2006). "The Two Micron All Sky Survey (2MASS)". The Astronomical Journal. 131 (2): 1163–1183. Bibcode:2006AJ....131.1163S. doi:10.1086/498708. ISSN 0004-6256. S2CID 18913331.
- ^ Abazajian, Kevork N.; et al. (2009). "The Seventh Data Release of the Sloan Digital Sky Survey". The Astrophysical Journal Supplement Series. 182 (2): 543–558. arXiv:0812.0649. Bibcode:2009ApJS..182..543A. doi:10.1088/0067-0049/182/2/543. S2CID 14376651.
- ^ a b c Tully, R. Brent; et al. (2016). "Cosmicflows-3". The Astronomical Journal. 152 (2): 21. arXiv:1605.01765. Bibcode:2016AJ....152...50T. doi:10.3847/0004-6256/152/2/50. S2CID 250737862. 50.
- ^ a b "NGC 4365". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-12.
- ^ a b c d Davies, Roger L.; et al. (February 2001). "Galaxy Mapping with the SAURON Integral-Field Spectrograph: The Star Formation History of NGC 4365". The Astrophysical Journal. 548 (1): L33 – L36. arXiv:astro-ph/0011254. Bibcode:2001ApJ...548L..33D. doi:10.1086/318930.
- ^ a b c Blom, Christina; et al. (April 2014). "The SLUGGS Survey: new evidence for a tidal interaction between the early-type galaxies NGC 4365 and NGC 4342". Monthly Notices of the Royal Astronomical Society. 439 (3): 2420–2431. arXiv:1401.5128. Bibcode:2014MNRAS.439.2420B. doi:10.1093/mnras/stu095.
- ^ "The elliptical galaxy NGC 4365". www.eso.org. European Southern Observatory. Retrieved 2020-10-28.
- ^ a b Larsen, S. S.; et al. (November 1, 2005). "Globular clusters in NGC 4365: new K-band imaging and a reassessment of the case for intermediate-age clusters". Astronomy & Astrophysics. 443 (2): 413–433. arXiv:astro-ph/0508181. Bibcode:2005A&A...443..413L. doi:10.1051/0004-6361:20053379. S2CID 1358900.
- ^ "NGC4365CXO - NGC 4365 Chandra LMXB Catalog". heasarc.gsfc.nasa.gov. Goddard Space Flight Center. Retrieved 2020-10-28.
- ^ a b Brodie, Jean P.; et al. (June 1, 2005). "Old Globular Clusters Masquerading as Young in NGC 4365?". The Astronomical Journal. 129 (6): 2643–2653. arXiv:astro-ph/0502467. Bibcode:2005AJ....129.2643B. doi:10.1086/429889. S2CID 13987584.
- ^ a b Surma, P.; Bender, R. (June 1995). "Relics of dissipational merging and past violent starbursts in elliptical galaxies - the gE galaxy NGC 4365". Astronomy and Astrophysics. 298: 405. Bibcode:1995A&A...298..405S.
- ^ Kundu, Arunav; et al. (November 2005). "The Ages of Globular Clusters in NGC 4365 Revisited with Deep HST Observations". The Astrophysical Journal. 634 (1): L41 – L44. arXiv:astro-ph/0510311. Bibcode:2005ApJ...634L..41K. doi:10.1086/498746.
- ^ Statler, Thomas S.; et al. (2004). "Long-lived triaxiality in the dynamically old elliptical galaxy NGC 4365: a limit on chaos and black hole mass". Monthly Notices of the Royal Astronomical Society. 353 (1): 1–14. arXiv:astro-ph/0406103. Bibcode:2004MNRAS.353....1S. doi:10.1111/j.1365-2966.2004.08062.x.
External links
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Media related to NGC 4365 at Wikimedia Commons- "Results for object NGC 4365 (NGC 4365)". NASA/IPAC Extragalactic Database. California Institute of Technology. Retrieved 2020-12-12.
