Massive M87 Black Hole Discovered with Supercomputer

[Astronuc]

It was thought to have a mass of about 3 billion sun. Now it's estimated mass is 6.4 billion suns.

Background

The Supermassive Black Hole of M87 and the Kinematics of Its Associated Gaseous Disk
http://www.iop.org/EJ/article/0004-637X/489/2/579/36331.text.html

http://csep10.phys.utk.edu/astr162/lect/active/smblack.html

http://hubblesite.org/newscenter/archive/releases/1994/23

Spectacular Flaring In Extragalactic Jet From M87's Black Hole
http://www.sciencedaily.com/releases/2009/04/090414163735.htm

Imaging the Black Hole Silhouette of M87: Implications for Jet Formation and Black Hole Spin
http://adsabs.harvard.edu/abs/2009ApJ...697.1164B


But now (announced at 214th meeting of the American Astronomical Society by Karl Gebhardt and the UT team)
Texas-sized computer finds most massive black hole in galaxy M87
http://www.astronomy.com/asy/default.aspx?c=a&id=8337

Astronomers Karl Gebhardt from The University of Texas at Austin and Jens Thomas from the Max Planck Institute for Extraterrestrial Physics have used new computer modeling techniques to discover that the black hole at the heart of M87, one of the largest nearby giant galaxies, is two to three times more massive than previously thought. Weighing in at 6.4 billion times the Sun's mass, it is the most massive black hole measured with a robust technique, and it suggests that the accepted black hole masses in nearby large galaxies may be off by similar amounts. This has consequences for theories of how galaxies form and grow, and might even solve a long-standing astronomical paradox.
. . . .
To model M87, Gebhardt and Thomas used one of the world's most powerful supercomputers, the Lonestar system at The University of Texas at Austin's Texas Advanced Computing Center. Lonestar is a Dell Linux cluster with 5,840 processing cores and can perform 62 trillion floating-point operations per second. (Today's top-of-the-line laptop computer has two cores and can perform up to 10 billion floating-point operations per second.)

Gebhardt and Thomas' model of M87 was more complicated than previous models of the galaxy because, in addition to modeling its stars and black hole, it takes into account the galaxy's "dark halo" - a spherical region surrounding a galaxy that extends beyond its main visible structure, containing the galaxy's mysterious "dark matter."
. . . .

Hopefully the model is consistent with other observations.

For the public:
A Real Whopper: Black Hole Is Most Massive Known
http://news.yahoo.com/s/space/20090608/sc_space/arealwhopperblackholeismostmassiveknown

 

[marcus]

Good find!
M87 is estimated 3x the mass of Milkyway galaxy.
The mass of the black hole is awesome.

I looked up the article by Gebhardt and Thomas on arxiv:
http://arxiv.org/abs/0906.1492
The Black Hole Mass, Stellar M/L, and Dark Halo in M87
Karl Gebhardt, Jens Thomas
12 pages, accepted for publication in the Astrophysical Journal
(Submitted on 8 Jun 2009)
"We model the dynamical structure of M87 (NGC4486) using high spatial resolution long-slit observations of stellar light in the central regions, two-dimensional stellar light kinematics out to half of the effective radius, and globular cluster velocities out to 8 effective radii. We simultaneously fit for four parameters, black hole mass, dark halo core radius, dark halo circular velocity, and stellar mass-to-light ratio. We find a black hole mass of 6.4(+-0.5)x10^9 Msun(the uncertainty is 68% confidence marginalized over the other parameters). ..."

The article confirms the estimate of 6.4 billion solar masses which was in the astronomy.com article you quoted.

So (incidental information) it would have a radius of about 12 billion miles. (Two miles per each solar mass). Big suckerrr.EDIT:
The next post mentions OJ 287, about which we have a mass estimate of 18 billion solar which I am not sure has been confirmed. The estimate is made by an unusual method---assuming that the OJ 287 hole is really two holes, a small one of about 100 million solar (no way of telling exactly) orbiting a big one---and then mass is determined from apparent orbit precession. But one can't see any of this actually happen, only infer from the record of radiation.
Here is the article by Valtonen et al that reported the OJ 287 bh mass calculation. It was published in Nature magazine (a careful peer-reviewer)
http://arxiv.org/abs/0809.1280v1
==excerpt==
It was not until the early 2007 that there were enough data to calculate a definite orbit¹¹. The precession rate of the major axis of this orbit is 39.0 degrees per orbit, the eccentricity of the orbit is 0.663, and the mass of the primary black hole is 18.0×109 solar masses. These values are reasonable: merging binaries are expected to have eccentricities similar to this at intermediate stages of evolution20, and the mass of the black hole is at the upper end of the mass range in quasars21 (which is encouraging, as OJ287 is among the brightest quasars).
==endquote==

EDIT:
Estimates of mass of galaxies are remarkably uncertain. For our own Milkyway galaxy estimates vary by 20 percent. As for M87, I have seen estimates that it is 3x the mass of Milky, and also that it is 4x the mass of Milky. Given the uncertainty, these are consistent. I wouldn't quibble which one is "righter".

 

[Orion1]

OJ 287 - galaxy...

A supermassive black hole is a black hole with a mass of the order of between 10^5 and 10^10 solar masses.

Our galactic central black hole is calculated to have a mass of approximately 4.1 million solar masses

Astronomers believe that the black hole in the M87 galaxy has a mass of approximately 6.4 billion (6.4×10^9) solar masses.

As of November 2008, another binary pair, in OJ 287, contains the most massive black hole known, with a mass estimated at 18 billion solar masses.

Name, galaxy mass, center BH mass(es):
MW:
0.58 × 10^12 M☉
4.1 × 10^6 M☉ (± 0.6)

M87:
2.4 × 10^12 M☉ (± 0.6)
6.4 × 10^9 M☉ (± 0.5)

OJ 287:
unknown
1.8 × 10^10 M☉
1 × 10^8 M☉

I could not locate the total mass and uncertainty data for OJ 287, clarification requested?

MW mass estimate table:
0.58 × 10^12 M☉ (Wikipedia)
0.6 x 10^12 M☉ (Imamura, James)
0.8 (+1.2)(-0.2) x 10^12 M☉ (NFW)
1.0 x 10^12 M☉ (Klypin et al. 2002)
1.2 (+1.8)(-0.5) x 10^12 M☉ (TF)
1.5 (±0.1) x 10^12 M☉ (NFW)
1.9 (+3.6)(−1.7) x 10^12 M☉ (W&E99)

I pulled the mass tables for MW from two of the sources cited by Wikipedia, none of which states the value cited in actual article or uncertainty data, clarification requested?
[/Color]
Reference:
http://en.wikipedia.org/wiki/Milky_Way#Galactic_center"
http://en.wikipedia.org/wiki/Messier_87"
http://en.wikipedia.org/wiki/OJ_287"
http://arxiv.org/PS_cache/astro-ph/pdf/0506/0506102v2.pdf"

 

[Chronos]

Im not yet sold on binary black hole systems, IMO, stellar mass black holes are formed by binary neutron star collisions. It is possible something very weird could occur in four star systems. That would be interesting.