Astronomers reveal true colors of evolving galactic beasts

August 07, 2019

Astronomers have identified a rare moment in the life of some of the universe's most energetic objects.

Quasars were first observed 60 years ago, but their origins still remain a mystery.

Now researchers at Durham University, UK, have spotted what they suggest is a "brief transition phase" in the development of these galactic giants that could shed light on how quasars and their host galaxies evolve.

The research is published in Monthly Notices of the Royal Astronomical Society.

Quasars are powered by the energy from supermassive black holes at their centres as they feed on surrounding gases.

They are thousands of times brighter than galaxies like our Milky Way and the majority are blue in colour.

However, a significant number are red as they are viewed through huge clouds of dust and gas that obscure them from view.

The conventional view of red quasars is that they are actually blue quasars that are angled away from our line-of-sight.

Instead, the Durham team has ruled this model out and have shown that red quasars are like-ly to be the result of a brief, but violent, phase in the evolution of galaxies when the black hole ejects a large amount of energy into the surrounding clouds of dust and gas.

This injection of energy blows away the dust and gas to reveal a blue quasar.

Observations using radio telescopes support this theory by showing that black holes at the centre of red quasars produce a greater amount of radio emission than those at the centre of blue quasars.

Lead author Lizelke Klindt, a PhD researcher in Durham University's Centre for Extragalactic Astronomy, said: "How quasars develop has been the cause of significant uncertainty.

"What our results suggest is that quasars undergo a brief transition phase, changing colour from red to blue, when they emerge from the deep shroud of dust and gas surrounding them.

"What we believe we are seeing is a rare but important step in the life of these galactic beasts during galaxy evolution when their black holes are starting to shape their environments."

The researchers studied 10,000 red and blue quasars as they would have been seen seven to 11 billion years ago when the universe was relatively young using archival data from the Sloan Digital Sky Survey and the Very Large Array radio astronomy observatory.

They say their research could also tell us more about galaxy evolution.

Co-author Professor David Alexander, Head of Astronomy, at Durham University, said: "We expect that during this transition phase the energy from the supermassive black hole will burn off the gas needed to form stars.

"Without the gas the galaxy cannot continue to grow, so what we are possibly seeing is the start of a quasar effectively ending the life of the galaxy by destroying the very thing it needs to survive."

The researchers say the next step in their research is to use more in-depth data to understand the finer details of this transition phase.
-end-
The research was funded by a Faculty of Science Durham Doctoral Scholarship, the Science and Technology Facilities Council, a European Union COFUND/Durham Junior Research Fel-lowship and the Swiss National Science Foundation.

Durham University

Related Science Articles from Brightsurf:

75 science societies urge the education department to base Title IX sexual harassment regulations on evidence and science
The American Educational Research Association (AERA) and the American Association for the Advancement of Science (AAAS) today led 75 scientific societies in submitting comments on the US Department of Education's proposed changes to Title IX regulations.

Science/Science Careers' survey ranks top biotech, biopharma, and pharma employers
The Science and Science Careers' 2018 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Science in the palm of your hand: How citizen science transforms passive learners
Citizen science projects can engage even children who previously were not interested in science.

Applied science may yield more translational research publications than basic science
While translational research can happen at any stage of the research process, a recent investigation of behavioral and social science research awards granted by the NIH between 2008 and 2014 revealed that applied science yielded a higher volume of translational research publications than basic science, according to a study published May 9, 2018 in the open-access journal PLOS ONE by Xueying Han from the Science and Technology Policy Institute, USA, and colleagues.

Prominent academics, including Salk's Thomas Albright, call for more science in forensic science
Six scientists who recently served on the National Commission on Forensic Science are calling on the scientific community at large to advocate for increased research and financial support of forensic science as well as the introduction of empirical testing requirements to ensure the validity of outcomes.

World Science Forum 2017 Jordan issues Science for Peace Declaration
On behalf of the coordinating organizations responsible for delivering the World Science Forum Jordan, the concluding Science for Peace Declaration issued at the Dead Sea represents a global call for action to science and society to build a future that promises greater equality, security and opportunity for all, and in which science plays an increasingly prominent role as an enabler of fair and sustainable development.

PETA science group promotes animal-free science at society of toxicology conference
The PETA International Science Consortium Ltd. is presenting two posters on animal-free methods for testing inhalation toxicity at the 56th annual Society of Toxicology (SOT) meeting March 12 to 16, 2017, in Baltimore, Maryland.

Citizen Science in the Digital Age: Rhetoric, Science and Public Engagement
James Wynn's timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ.

Science/Science Careers' survey ranks top biotech, pharma, and biopharma employers
The Science and Science Careers' 2016 annual Top Employers Survey polled employees in the biotechnology, biopharmaceutical, pharmaceutical, and related industries to determine the 20 best employers in these industries as well as their driving characteristics.

Three natural science professors win TJ Park Science Fellowship
Professor Jung-Min Kee (Department of Chemistry, UNIST), Professor Kyudong Choi (Department of Mathematical Sciences, UNIST), and Professor Kwanpyo Kim (Department of Physics, UNIST) are the recipients of the Cheong-Am (TJ Park) Science Fellowship of the year 2016.

Read More: Science News and Science Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.