Astronomers Find Wandering Massive Black Holes in Dwarf Galaxies

Roughly half of the newly-discovered black holes are not at the centers of their galaxies

Credit: Sophia Dagnello, NRAO/AUI/NSF

Astronomers seeking to learn about the mechanisms that formed massive black holes in the early history of the Universe have gained important new clues with the discovery of 13 such black holes in dwarf galaxies less than a billion light-years from Earth.

These dwarf galaxies, more than 100 times less massive than our own Milky Way, are among the smallest galaxies known to host massive black holes. The scientists expect that the black holes in these smaller galaxies average about 400,000 times the mass of our Sun.

“We hope that studying them and their galaxies will give us insights into how similar black holes in the early Universe formed and then grew, through galactic mergers over billions of years, producing the supermassive black holes we see in larger galaxies today, with masses of many millions or billions of times that of the Sun,” said Amy Reines of Montana State University.

Reines and her colleagues used the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) to make the discovery, which they are reporting at the American Astronomical Society’s meeting in Honolulu, Hawaii.

Reines and her collaborators used the VLA to discover the first massive black hole in a dwarf starburst galaxy in 2011. That discovery was a surprise to astronomers and spurred a radio search for more.

The scientists started by selecting a sample of galaxies from the NASA-Sloan Atlas, a catalog of galaxies made with visible-light telescopes. They chose galaxies with stars totalling less than 3 billion times the mass of the Sun, about equal to the Large Magellanic Cloud, a small companion of the Milky Way. From this sample, they picked candidates that also appeared in the National Radio Astronomy Observatory’s Faint Images of the Radio Sky at Twenty centimeters (FIRST) survey, made between 1993 and 2011.

They then used the VLA to make new and more sensitive, high-resolution images of 111 of the selected galaxies.

“The new VLA observations revealed that 13 of these galaxies have strong evidence for a massive black hole that is actively consuming surrounding material. We were very surprised to find that, in roughly half of those 13 galaxies, the black hole is not at the center of the galaxy, unlike the case in larger galaxies,” Reines said

The scientists said this indicates that the galaxies likely have merged with others earlier in their history. This is consistent with computer simulations predicting that roughly half of the massive black holes in dwarf galaxies will be found wandering in the outskirts of their galaxies.

“This work has taught us that we must broaden our searches for massive black holes in dwarf galaxies beyond their centers to get a more complete understanding of the population and learn what mechanisms helped form the first massive black holes in the early Universe,” Reines said.

Reines worked with James Condon, of the National Radio Astronomy Observatory; Jeremy Darling, of the University of Colorado, Boulder; and Jenny Greene, of Princeton University. The astronomers are publishing their results in the Astrophysical Journal. (Preprint )

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.


Media Contact:

Dave Finley, Public Information Officer
(575) 835-7302

In Other News…

Big Astronomy Planetarium Show Premiers September 26

Big Astronomy planetarium show premiers September 26 Turn your phone into a planetarium with innovative and immersive 360° streaming San Francisco – The Big Astronomy worldwide premiere is coming soon to a smart phone or connected device near you! On September 26 at...

ALMA Discovers Misaligned Rings in Planet-Forming Disk Around Triple Stars

Using the Atacama Large Millimeter/submillimeter Array (ALMA), two teams of astronomers have for the first time discovered a planet-forming disk with misaligned rings around a triple star system, called GW Orionis. The astronomers give two possible scenarios for the...

Why North Carolina Outsourced Election Cybersecurity to a ‘CISO-as-a-Service’

The following is press coverage on Woodstar Labs' involvement with North Carolina's election security, courtesy of Faced with mounting cybersecurity needs headed toward the presidential election, but lacking the financial resources to build out a more...

A Cyber-Risk We’re Not Prepared For: What if the Power Grid Collapsed and America Went Dark?

The following is press coverage on the NCGR's new report, courtesy of EVERY CATASTROPHE comes as a shock, but many shouldn’t come as a surprise. Just as we knew a pandemic was a possibility yet failed to plan for it, power-grid collapse is a threat...

Grid Security And Cyber Defense Cannot Fall On Deaf Ears, Experts Warn

The following is press coverage on the NCGR's new report, courtesy of If the electrical grid is knocked out for long periods, the damage to the American economy would be insurmountable. And the country’s enemies know that. That is why its brain trust is...

Coverage on National Commision on Grid Resilience’s (NCGR) Latest Report

The following is press coverage on the NCGR's new report, courtesy of   Dive Brief: A new report from the National Commission on Grid Resilience (NCGR) calls for declassifying and giving utilities greater access to information about threats...

Woodstar Labs Welcomes New Wave of Cyber Analysts

Woodstar Labs, a subsidiary of AUI focused on cutting-edge-cybersecurity solutions, microelectronics, eLearning, and STEM education welcomes a new cohort of Cyber Analysts. Woodstar labs is excited to work with this talented group of young professionals as we continue...

AUI Statement on Racial Equity

As the nation continues to mourn and respond to the unjust death of George Floyd, there is no doubt that violent race-related incidents and the subsequent protests and clashes are the most urgent need for us as a society to address. Further, to address them, we must...

2020 AUI Scholarship Winners

Below are the winners of the 2020 AUI Scholarship conducted by International Scholarship and Tuition Services, Inc. These students will each receive an award of $3,500 per year to aid in defraying expenses at the college or university of their choice. Lexington Miller...

Big Astronomy Wins Big

Big Astronomy wins “Best Astronomy Education” Award in the Dome Under Fulldome Film Festival. Melbourne: The Dome Under Fulldome Film Festival hosted its first planetarium film fest in Melbourne, Australia, on February 8 – 9. Big Astronomy: People Places Discoveries,...

You are now leaving AUI

You will be redirected to the related partnering organization's website.

You will be redirected to
in 4 seconds...

Click the link above to continue or CANCEL