Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Quiet quasar has apparently eaten its fill

11.01.2016

Astronomers with the Sloan Digital Sky Survey (SDSS) announced that a distant quasar ran out of gas.

Their conclusions, reported Jan. 8 at the American Astronomical Society meeting in Kissimmee, Florida, clarify why quasar SDSS J1011+5442 changed so dramatically in the handful of years between observations.

"We are used to thinking of the sky as unchanging," said University of Washington astronomy professor Scott Anderson, who is principal investigator of the SDSS's Time-Domain Spectroscopic Survey. "The SDSS gives us a great opportunity to see that change as it happens."


This is an artist's conception of the "changing-look quasar" as is appared in early 2015. The glowing blue region shows the last of the gas being swallowed by central black hole as it shuts off. The spectrum is the previous one obtained by the SDSS in 2003.

Credit: Dana Berry / SkyWorks Digital, Inc.

Quasars are the compact area at the center of large galaxies, usually surrounding a massive black hole. The black hole at the center of J1011+5442, for example, is some 50 million times more massive than our sun.

As the black hole gobbles up superheated gas, it emits vast amounts of light and radio waves. When SDSS astronomers made their first observations of J1011+5442 in 2003, they measured the spectrum of the quasar, which let them understand the properties of the gas being swallowed by the black hole. In particular, the prominent "hydrogen-alpha" line in the spectrum revealed how much gas was falling into the central black hole.

The SDSS measured another spectrum for this quasar in early 2015, and noticed a huge decrease between 2003 and 2015. The team made use of additional observations by other telescopes over those 12 years to narrow down the period of change.

"The difference was stunning and unprecedented," said UW astronomy graduate student John Ruan, a member of the research team. "The hydrogen-alpha emission dropped by a factor of 50 in less than 12 years, and the quasar now looks like a normal galaxy."

The change was so great that throughout the SDSS collaboration and astronomy community, the quasar became known as a "changing-look quasar." The black hole is still there, of course, but over the past 10 years, it appears to have swallowed all the gas in its vicinity. With the gas fallen into the black hole, the SDSS team were unable to detect the spectroscopic signature of the quasar.

"This is the first time we've seen a quasar shut off this dramatically, this quickly," said lead author Jessie Runnoe, a postdoctoral researcher at Pennsylvania State University.

Before Runnoe, Ruan and their colleagues could come to this conclusion, they had to rule out two other possibilities. A thick layer of dust could have passed through the host galaxy, obscuring their view of the black hole at its center.

But, they concluded that there is no way that any dust cloud could have moved fast enough to cause a 50-fold drop in brightness in just two years. Another possibility is that the bright quasar in 2003 was just a temporary flare caused by the black hole ripping apart a nearby star. While this possibility has been invoked in similar cases, it cannot to explain the fact that the changing-look quasar had been shining for many years before it turned off.

The team's conclusion is that the quasar has used up all the glowing-hot gas in its immediate vicinity, leading to a rapid drop in brightness.

"Essentially, it has run out of food, at least for the moment," says Runnoe. "We were fortunate to catch it before and after."

The changing-look quasar is the first major discovery reported for the Time-Domain Spectroscopic Survey, one component of SDSS's fourth phase, which will continue for the next several years.

"We found this quasar because we went back to study thousands of quasars seen before," said Anderson. "This discovery was only possible because the SDSS is so deep and has continued so long."

###

For more information, contact Runnoe at jcr26@psu.edu or 814-863-9343, Ruan at jruan@astro.washington.edu or 206-543-5185 and Anderson at anderson@astro.washington.edu or 206-685-2392.

Adapted from a release prepared by the American Astronomical Society.

Media Contact

James Urton
jurton@uw.edu
206-543-2580

 @UW

http://www.washington.edu/news/ 

James Urton | EurekAlert!

Further reports about: SDSS Spectroscopic Telescopes astronomy black hole massive black hole radio waves

More articles from Physics and Astronomy:

nachricht Applicability of dynamic facilitation theory to binary hard disk systems
08.12.2016 | Nagoya Institute of Technology

nachricht Will Earth still exist 5 billion years from now?
08.12.2016 | KU Leuven

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>