Dartmouth astrophysicists and their colleagues have not only proven that a supermassive black hole exists in a place where it isn't supposed to be, but in doing so have opened a new door to what things were like in the early universe.
Henize 2-10 is a small irregular galaxy that is not too far away in astronomical terms -- 30 million light-years. "This is a dwarf starburst galaxy -- a small galaxy with regions of very rapid star formation -- about 10 percent of the size of our own Milky Way," says co-author Ryan Hickox, an assistant professor in Dartmouth's Department of Physics and Astronomy. "If you look at it, it's a blob, but it surprisingly harbors a central black hole."
Hickox says there may be similar small galaxies in the known universe, but this is one of the only ones close enough to allow detailed study. Lead author Thomas Whalen, Hickox and a team of other researchers have now analyzed a series of four X-ray observations of Henize 2-10 using three space telescopes over 13 years, providing conclusive evidence for the existence of a black hole.
Their findings appear as an online preprint to be published in The Astrophysical Journal Letters. A PDF also is available on request.
Suspicions about Henize 2-10 first arose in 2011 when another team, that included some of the co-authors, first looked at galaxy Henize 2-10 and tried to explain its behavior. The observed dual emissions of X-ray and radio waves, often associated with a black hole, gave credence to the presence of one. The instruments utilized were Japan's Advanced Satellite for Cosmology and Astrophysics (1997), the European Space Agency's XMM-Newton (2004, 2011) and NASA's Chandra X-ray Observatory (2001).
"The galaxy was bright in 2001, but it has gotten less bright over time," says Hickox. "This is not consistent with being powered only by star formation processes, so it almost certainly had to have a small supermassive black hole -- small compared to the largest supermassive black holes in massive elliptical galaxies, but is still a million times the mass of the sun."
A characteristic of supermassive black holes is that they do change with time -- not a huge amount, explains Hickox, "and that is exactly what Tom Whalen found," he says. "This variability definitely tells us that the emission is coming from a compact source at the center of this system, consistent with it being a supermassive black hole."
While supermassive black holes are typically found in the central bulges of galaxies, Henize 2-10 has no bulge. "All the associations that people have made between galaxies and black holes tell us there ought to be no black hole in this system," says Whalen, but the team has proven otherwise. Whalen, a recent Dartmouth graduate, is now a member of the Chandra X-ray Center team at the Harvard-Smithsonian Center for Astrophysics.
A big question is where black holes come from. "When people try to simulate where the galaxies come from, you have to put in these black holes at the beginning, but we don't really know what the conditions were. These dwarf starburst galaxies are the closest analogs we have in the universe around us now, to the first galaxies early in the universe," says Whalen.
The authors conclude: "Our results confirm that nearby star-forming galaxies can indeed form massive black holes and that by implication so can their primordial counterparts."
"Studying those to get some sense of what might have happened very early in the universe is very powerful," says Hickox.
Broadcast studios: Dartmouth has TV and radio studios available for interviews. For more information, visit: http://www.
John Cramer | EurekAlert!
Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles
Engineering team images tiny quasicrystals as they form
18.08.2017 | Cornell University
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences