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Post Info TOPIC: Messier 85


Posts: 131433
NGC 4382

Messier 85 (also known as M85, NGC 4382, MCG 3-32-29, UGC 7508 and PGC 40515) is a magnitude +9.1 lenticular galaxy with a surface area of 7.1' x 5.5' located 60 million light years away in the constellation Coma Berenices.
It is the brightest member of the Virgo Cluster. The galaxy was discovered by French astronomer Pierre Méchain at the Hotel de Cluny on the 4th March 1781. Charles Messier added it to his catalogue together with six other galaxies and the globular cluster M92 on the 18th March.
M85 is approximately 124 x 96,000 lightyears in size; slightly larger than the Milky Way.
In the immediate vicinity of Messier 85 is spiral galaxy NGC 4394, and a small elliptical galaxy called MCG 3-32-38. These systems are roughly the same distance as Messier 85 and is in all probability satellite galaxies of M85.
Messier 85 hosted Type Ia supernova 1960R on the 19th December 1960, which reached a maximum brightness of 11.6.

Right Ascension 12h 25m 24.23s Declination +18° 11' 26.9"




Posts: 131433
Messier 85

Title: Is there a black hole in NGC 4382?
Authors: Kayhan Gultekin, Douglas O. Richstone, Karl Gebhardt, S. M. Faber, Tod R. Lauer, Ralf Bender, John Kormendy, Jason Pinkney

We present HST STIS observations of the galaxy NGC 4382 (M85) and axisymmetric models of the galaxy to determine mass-to-light ration (M/L, V-band) and central black hole mass (M_BH). We find M/L = 3.74 ±0.1 (solar units) and M_BH = 1.3 (+5.2, -1.2) x 10^7 M_sun at an assumed distance of 17.9 Mpc, consistent with no black hole. The upper limit, M_BH < 9.6 x 10^7 M_sun (2{\sigma}) or M_BH < 1.4 x 10^8 M_sun (3{\sigma}) is consistent with the current M-{\sigma} relation, which predicts M_BH = 8.8 x 10^7 M_sun at {\sigma}_e = 182 km/s, but low for the current M-L relation, which predicts M_BH = 7.8 x 10^8 M_sun at L_V = 8.9 x 10^10 L_sun,V. HST images show the nucleus to be double, suggesting the presence of a nuclear eccentric stellar disk, in analogy to the Tremaine disk in M31. This conclusion is supported by the HST velocity dispersion profile. Despite the presence of this non-axisymmetric feature and evidence of a recent merger, we conclude that the reliability of our black hole mass determination is not hindered. The inferred low black hole mass may explain the lack of nuclear activity.

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