’Middleweight’ black hole discovered in space in world-first, Queensland scientist says

A Queensland scientist has played a vital role in the world-first discovery of a “middleweight” black hole in space, spending 40 years searching the universe to find it.

University of Queensland astronomer Associate Professor Holger Baumgardt said it was the missing link between small and super-sized black holes.

More…

The third one I’ve heard of. Eg., There was this one from 2012.

Scientists find evidence of first ‘middleweight’ black hole July 6, 2012

They’re not common.

Here’s one from 2002, which also refers to an earlier find in 2001.

https://www.newscientist.com/article/dn2816-middleweight-black-holes-are-missing-link/

Tau.Neutrino said:

’Middleweight’ black hole discovered in space in world-first, Queensland scientist says

A Queensland scientist has played a vital role in the world-first discovery of a “middleweight” black hole in space, spending 40 years searching the universe to find it.

University of Queensland astronomer Associate Professor Holger Baumgardt said it was the missing link between small and super-sized black holes.

More…

47 Tucanae. That’s the key amazing fact about this black hole. Very famous, and very near, only 16,700 light years away. Most if not all of the others were found in further galaxies.

From Wikipedia.

Intermediate-mass black holes and candidates

Cigar Galaxy (Messier 82, NGC 3034)
1E1740.7-2942 (Great Annihilator), 340 LY from Sgr A*
CO-0.40-0.22
GCIRS 13E
HLX-1
M82 ×-1
Messier 15 (NGC 7078)
Messier 110 (NGC 205)
NGC 1313 ×-1
NGC 1313 ×-2
Sculptor Galaxy (NGC 253)
Triangulum Galaxy (Messier 33, NGC 598)

Let’s see if i can find out what those black hole masses are?

> Intermediate-mass black holes and candidates

In the Milky Way

2,200 – 47 Tucanae – a star cluster 16,700 light years from Earth
198 – 1E1740.7-2942 (Great Annihilator), 340 LY from Sgr A* – a confirmed black hole near the centre of the Milky Way
100,000 – CO-0.40-0.22 – this is a possible black hole near the centre of the Milky Way
1,300 – GCIRS 13E – this is a possible black hole near the centre of the Milky Way
mass unknown – Messier 15 (NGC 7078) – a globular cluster 33,600 light-years from Earth – black hole not yet confirmed

In other galaxies

500 – HLX-1 – located in the galaxy ESO 243-49
400+-100 – M82 ×-1
200 to 5,000 – Cigar Galaxy (Messier 82, NGC 3034) – duplicate entry, this the same as M82 ×-1?
20,000 – “Michael Rich of the University of California at Los Angeles found a 20,000 solar mass black hole in a cluster in the Andromeda Galaxy, 2.2 million light years away”. “The globular cluster G1 (Mayall II) in M31 has been claimed to host a central ~20,000 M☉ black hole, but these claims have been controversial.”
mass unknown – Messier 110 (NGC 205) – companion of Andromeda galaxy, black hole not yet confirmed
mass unknown – NGC 1313 ×-1 – black hole not yet confirmed
mass unknown – NGC 1313 ×-2 – black hole not yet confirmed
mass unknown – Sculptor Galaxy (NGC 253) – unidentified X-ray source near but not at the galaxy centre
mass unknown <3,000 – Triangulum Galaxy (Messier 33, NGC 598) – unidentified X-ray source at the galaxy centre

mollwollfumble said:

Let’s see if i can find out what those black hole masses are?

> Intermediate-mass black holes and candidates

In the Milky Way

2,200 – 47 Tucanae – a star cluster 16,700 light years from Earth
198 – 1E1740.7-2942 (Great Annihilator), 340 LY from Sgr A* – a confirmed black hole near the centre of the Milky Way
100,000 – CO-0.40-0.22 – this is a possible black hole near the centre of the Milky Way
1,300 – GCIRS 13E – this is a possible black hole near the centre of the Milky Way
mass unknown – Messier 15 (NGC 7078) – a globular cluster 33,600 light-years from Earth – black hole not yet confirmed

In other galaxies

500 – HLX-1 – located in the galaxy ESO 243-49
400+-100 – M82 ×-1
200 to 5,000 – Cigar Galaxy (Messier 82, NGC 3034) – duplicate entry, this the same as M82 ×-1?
20,000 – “Michael Rich of the University of California at Los Angeles found a 20,000 solar mass black hole in a cluster in the Andromeda Galaxy, 2.2 million light years away”. “The globular cluster G1 (Mayall II) in M31 has been claimed to host a central ~20,000 M☉ black hole, but these claims have been controversial.”
mass unknown – Messier 110 (NGC 205) – companion of Andromeda galaxy, black hole not yet confirmed
mass unknown – NGC 1313 ×-1 – black hole not yet confirmed
mass unknown – NGC 1313 ×-2 – black hole not yet confirmed
mass unknown – Sculptor Galaxy (NGC 253) – unidentified X-ray source near but not at the galaxy centre
mass unknown <3,000 – Triangulum Galaxy (Messier 33, NGC 598) – unidentified X-ray source at the galaxy centre

How do they estimate the density of dark matter when there are so many black holes of unknown mass?

Is the total mass of black holes significant as a total contributor to Universe mass?

The Rev Dodgson said:

How do they estimate the density of dark matter when there are so many black holes of unknown mass?

Is the total mass of black holes significant as a total contributor to Universe mass?

You’ve answered your own question there. Black holes are rare. Galaxy rotation curves are the opposite of what would be expected of the mass of black holes was significant. If supermassive black holes had a significant fraction of galaxy mass then the central velocity would have to be very high. But the central velocity of galaxies is much slower than the speed further out.

Intermediate mass black holes are very rare, and together carry less than 1% of the supermassive black hole. Stellar mass black holes must be rare because if not then they would be detected in X rays. Mini-black holes must be rare because if not then they would show up either in searches for Machos or in affecting the orbits of Uranus and Neptune.

I have seen an upper limit on the possible total baryonic mass due to black holes, but can’t remember off hand whether it’s 2% or 0.2%, which makes it negligible relative to dark matter.