Quest for source of black hole dark matter

August 14, 2018 by Anne M Stark, Lawrence Livermore National Laboratory
LLNL scientists Michael Schneider, Will Dawson, Nathan Golovich and George Chapline look for black holes in the Lab’s telescope remote observing room. Credit: Julie Russell/LLNL.

Like a game of "hide and seek," Lawrence Livermore astrophysicists know that there are black holes hiding in the Milky Way, just not where.

If they find them toward the galactic bulge (a tightly packed group of ) and the Magellanic Clouds, then as massive as 10,000 times the mass of the sun might make up . If they are only toward the then they are probably just from a few dead stars.

Typically, to observe the Magellanic Clouds, scientists must travel to observatories in the Southern Hemisphere.

But recently, the LLNL team got a new tool that's a little closer to home to help them in the search. As part of the Space Science and Security Program and an LDRD project, LLNL has a new telescope remote observing room.

The team is using the observing room to conduct a gravitational survey of the Milky Way and Magellanic Clouds in search of intermediate mass black holes (approximately 10 to 10,000 times the mass of the sun) that may make up the majority of dark .

"The remote observing room enables us to control the National Optical Astronomers Observatory Blanco 4-meter telescope located in Chile at the Cerro Tololo Inter-American Observatory," said LLNL principal investigator Will Dawson. The team already has conducted its first observing run with the remote observing room.

The visible universe is composed of approximately 70 percent dark energy, 25 percent dark matter and 5 percent normal matter. However, dark matter has remained a mystery since it was first postulated in 1933. The MACHO Survey, led by Lawrence Livermore in the 1990s, sought to test whether dark matter was composed of baryonic massive compact halo objects (MACHOs). The survey concluded that baryonic MACHOs smaller than 10 solar masses could not account for more than 40 percent of the total dark matter mass.

Recently, the discovery of two merging black holes has renewed interest in MACHO dark matter composed of primordial black holes (formed in the early universe, before the first stars) with approximately 10 to 10,000 solar masses. This is an idea first proposed in 1975 by LLNL physicist and project co-investigator George Chapline. The most direct means of exploring this mass range is by searching for the gravitational microlensing signal in existing archival astronomical imaging and carrying out a next-generation microlensing survey with state-of-the-art wide-field optical imagers on telescopes 10 to 25 times more powerful than those used in the original MACHO surveys.

Microlensing is an astronomical effect predicted by Einstein's general theory of relativity. According to Einstein, when the light emanating from a star passes very close to another massive object (e.g., black hole) on its way to an observer on Earth, the gravity of the intermediary massive object will slightly bend and focus the light rays from the source star, causing the lensed background star to appear brighter than it normally would.

"We are developing a novel means of microlensing detection that will enable us to detect the parallactic microlensing signature associated with black holes in this mass range," Dawson said. "We will detect and constrain the fraction of dark matter composed of intermediate mass black holes and measure their spectrum in the Milky Way."

Explore further: Is dark matter made of primordial black holes?

Related Stories

Is dark matter made of primordial black holes?

April 20, 2018

Astronomers studying the motions of galaxies and the character of the cosmic microwave background radiation came to realize in the last century that most of the matter in the universe was not visible. About 84 percent of ...

How a star cluster ruled out MACHOs

August 10, 2016

Are massive black holes hiding in the halos of galaxies, making up the majority of the universe's mysterious dark matter? This possibility may have been ruled out by a star cluster in a small galaxy recently discovered orbiting ...

A new look at the nature of dark matter

March 6, 2017

The nature of the dark matter which apparently makes up 80% of the mass of the particles in the universe is still one of the great unsolved mysteries of present day sciences. The lack of experimental evidence, which could ...

How much of the universe is black holes?

June 17, 2014

We all fear black holes, but how many of them are there out there, really? Between the stellar mass black holes and the supermassive ones, just how much of our Universe is black holes?

Astronomers' model sheds light on microlensing event

October 30, 2012

One of the closest galaxies to the Milky Way almost got away with theft. However, new simulations convicted the Large Magellanic Cloud (LMC) of stealing stars from its neighbor, the Small Magellanic Cloud (SMC). And the crucial ...

Recommended for you

Japan space robots start asteroid survey

September 22, 2018

A pair of robot rovers have landed on an asteroid and begun a survey, Japan's space agency said Saturday, as it conducts a mission aiming to shed light on the origins of the solar system.

First to red planet will become Martians: Canada astronaut

September 22, 2018

Astronauts traveling through space on the long trip to Mars will not have the usual backup from mission control on Earth and will need to think of themselves as Martians to survive, Canada's most famous spaceman half-jokingly ...

Three NASA missions return first-light data

September 21, 2018

NASA's continued quest to explore our solar system and beyond received a boost of new information this week with three key missions proving not only that they are up and running, but that their science potential is exceptional. ...

Dwarf companion to EPIC 206011496 detected by astronomers

September 20, 2018

Using ESO's Very Large Telescope (VLT), European astronomers have uncovered the presence of an M-dwarf around the star EPIC 206011496. The newly found object is more than 60 percent less massive than our sun and is bounded ...

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

fthompson495
1 / 5 (2) Aug 14, 2018
Dark matter is a supersolid that fills 'empty' space, strongly interacts with ordinary matter and is displaced by ordinary matter. What is referred to geometrically as curved spacetime physically exists in nature as the state of displacement of the supersolid dark matter. The state of displacement of the supersolid dark matter is gravity.

The supersolid dark matter displaced by a galaxy pushes back, causing the stars in the outer arms of the galaxy to orbit the galactic center at the rate in which they do.
malapropism
5 / 5 (1) Aug 14, 2018
@fthompson495
Your comment doesn't seem to make much sense.

For dark matter to be a supersolid, it by definition must be in an ordered (solid) state yet behaving as a superfluid. This would seem to imply that it must therefore be composed of baryonic matter, since a supersolid (or superfluid) exists as a Bose-Einstein condensate and, as far as I'm aware, only baryons can be in this phase of matter. (Someone else might be able to clarify this if I'm wrong, however.)

If it is otherwise ordinary baryonic matter then it should be readily found by current science.

If you are suggesting that it is not ordinary baryonic matter in this special quantum state then you both need to state this (you don't) and also propose how non-baryonic matter can be shown to behave in this manner. Either way, at present you have simply put the argument at one further remove and don't seem to be advancing discussion of dark matter.

Perhaps you can explain? Or stop spamming this comment.
Bob West
1 / 5 (3) Aug 14, 2018
There is evidence of the supersolid dark matter every time a double-slit experiment is performed, as it is the supersolid dark matter that waves.
Bob West
1 / 5 (2) Aug 14, 2018
Wave-particle duality is a moving particle and its associated wave in the supersolid dark matter.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.