NGC 4395
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An ultraviolet image of NGC 4395 taken with GALEX. |
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| Observation data: J2000 epoch | |
|---|---|
| Constellation: | |
| Right ascension: | 12h 25m 48.9s[1] |
| Declination: | +33° 32′ 48″[1] |
| Redshift: | 319 ± 1 km/s[1] |
| Distance: | |
| Type: | SA(s)m[1] |
| Apparent dimensions (V): | 13′.2 × 11′.0[1] |
| Apparent magnitude (V): | 10.6[1] |
| Notable features: | |
| Other designations | |
| NGC 4399 through 4401,[2] UGC 7542,[1] PGC 40596[1] | |
| See also: Galaxy, List of galaxies | |
NGC 4395 is a low surface brightness spiral galaxy with a halo that is about 8′ in diameter. It has several wide areas of greater brightness running northwest to southeast. The one furthest southeast is the brightest. Three of the patches have their own NGC numbers: 4401, 4400, and 4399 running east to west.[2]
NGC 4395 is notable in that it contains one of the smallest supermassive black hole ever discovered. The central black hole has a mass of "only" 300,000 sun masses. The black hole was discovered in 1989, and had been judged to be between 55,000 and 65,000 sun masses. Recent estimates have thus quintupled the estimated size, but it is still far smaller than other black holes in its class. It is likely that is it so small because it has little material around it to add to its bulk. Indeed, stars are conspicuously absent in its immediate vicinity, and so it was "starved" down to that size or has never been able to fully grow, unlike most similar black holes.
[edit] External links
[edit] References
- ^ a b c d e f g h NASA/IPAC Extragalactic Database. Results for. Retrieved on November 4, 2006.
- ^ a b Kepple, George Robert; Glen W. Sanner (1998). The Night Sky Observer's Guide, Volume 2. Willmann-Bell, Inc., 48. ISBN 0-943396-60-3.
- http://space.com/scienceastronomy/050221_little_blackhole.html
- http://www.space.com/php/multimedia/imagedisplay/img_display.php?pic=ngc_4395_030527_02.jpg&cap=An+optical+photograph+of+NGC+4395%2C+which+has+no+central+bulge+but+does+contain+a+supermassive+black+hole+at+its+center.
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