Magnetic fields may be the key to black hole activity

(THIS ARTICLE IS COURTESY OF PHYS.ORG AND NASA)

 

Magnetic fields may be the key to black hole activity

October 17, 2018, NASA
Magnetic fields may be the key to black hole activity
Artist’s conception of the core of Cygnus A, including the dusty donut-shaped surroundings, called a torus, and jets launching from its center. Magnetic fields are illustrated trapping the dust in the torus. These magnetic fields could be …more

Collimated jets provide astronomers with some of the most powerful evidence that a supermassive black hole lurks in the heart of most galaxies. Some of these black holes appear to be active, gobbling up material from their surroundings and launching jets at ultra-high speeds, while others are quiescent, even dormant. Why are some black holes feasting and others starving? Recent observations from the Stratospheric Observatory for Infrared Astronomy, or SOFIA, are shedding light on this question.

SOFIA data indicate that magnetic fields are trapping and confining dust near the center of the active galaxy, Cygnus A, and feeding material onto the supermassive black hole at its center.

The , which attempts to explain the different properties of active galaxies, states that the core is surrounded by a donut-shaped dust cloud, called a torus. How this obscuring structure is created and sustained has never been clear, but these new results from SOFIA indicate that magnetic fields may be responsible for keeping the dust close enough to be devoured by the hungry black hole. In fact, one of the fundamental differences between active galaxies like Cygnus A and their less active cousins, like our own Milky Way, may be the presence or absence of a  around the black hole.

Although celestial magnetic fields are notoriously difficult to observe, astronomers have used polarized light—optical light from scattering and radio light from accelerating electrons—to study magnetic fields in galaxies. But optical wavelengths are too short and the radio wavelengths are too long to observe the torus directly. The infrared wavelengths observed by SOFIA are just right, allowing scientists, for the first time, to target and isolate the dusty torus.

Magnetic fields may be the key to black hole activity
Two images of Cygnus A layered over each other to show the galaxy’s jets glowing with radio radiation (shown in red). Quiescent galaxies, like our own Milky Way, do not have jets like this, which may be related to magnetic fields. The …more

SOFIA’s new instrument, the High-resolution Airborne Wideband Camera-plus (HAWC+), is especially sensitive to the infrared emission from aligned dust grains. This has proven to be a powerful technique to study magnetic fields and test a fundamental prediction of the unified model: the role of the dusty torus in the active-galaxy phenomena.

“It’s always exciting to discover something completely new,” noted Enrique Lopez-Rodriguez, a scientist at the SOFIA Science Center, and the lead author on the report of this new discovery. “These observations from HAWC+ are unique. They show us how infrared polarization can contribute to the study of galaxies.”

Recent observations of the heart of Cygnus A made with HAWC+ show infrared radiation dominated by a well-aligned dusty structure. Combining these results with archival data from the Herschel Space Observatory, the Hubble Space Telescope and the Gran Telescopio Canarias, the research team found that this powerful active galaxy, with its iconic large-scale jets, is able to confine the obscuring torus that feeds the supermassive black hole using a strong .

The results of this study were published in the July 10th issue of The Astrophysical Journal Letters.

Cygnus A is in the perfect location to learn about the role magnetic fields play in confining the dusty torus and channeling material onto the supermassive black hole because it is the closest and most powerful active galaxy. More observations of different types of galaxies are necessary to get the full picture of how magnetic fields affect the evolution of the environment surrounding . If, for example, HAWC+ reveals highly polarized  from the centers of active galaxies but not from quiescent , it would support the idea that magnetic fields regulate black hole feeding and reinforce astronomers’ confidence in the unified model of .

 Explore further: Black holes play hide-and-seek in low-luminosity radio galaxies

More information: Enrique Lopez-Rodriguez et al. The Highly Polarized Dusty Emission Core of Cygnus A, The Astrophysical Journal (2018). DOI: 10.3847/2041-8213/aacff5

Read more at: https://phys.org/news/2018-10-magnetic-fields-key-black-hole.html#jCp

China: New Tighter Controls On Streaming

(THIS ARTICLE IS COURTESY OF THE SHANGHAI DAILY NEWS)

CHINA’S press and publications regulator has ordered social media platforms featuring video and audio programs to obtain licenses.

The State Administration of Press, Publications, Radio, Film and Television recently issued a document strengthening the regulation of video and audio programs on social media platforms, such as Weibo and WeChat, it said in a statement yesterday.

If organizations and individuals operating online streaming services on Weibo or WeChat without licenses, the social platforms would be held responsible.

Platforms must monitor content to ensure it meets the “various requirements for managing video and audio programs,” the regulator said, adding that the content cannot exceed the license conditions.

Online platforms are also prohibited from offering access to Weibo or WeChat accounts that defy regulations.

53 Years Ago Today I Woke Up: 11-22-1963: The Day The NSA Murdered Our President

 

53 Years ago today I was a 7-year-old second grader at a very small country school in South-West Virginia. My world up until that time just revolved around my family, neighbors, and school. At this time I knew basically nothing about the outside world, we had an old black and white TV Set but we seldom got to watch it as kids and there was never ever a radio in our home. Mom and Dad never spoke of events outside of our community, State events or World events were simply not a part of our daily lives. To my parents defence we were very dirt poor, we lived on a little 8 acre farm way out in the country and both my parents were minimum wage factory workers who were simply trying to find a way to support our family of 5 from week to week. The most I knew about the outside world was that my brother who was 7 years older than me was a fan of someone/thing called the Chicago White Sox who had won the  world series (whatever that was) in 1959. All I knew about Chicago was that it was ‘a place’ somewhere and nothing more.

 

On November 22nd 1963 all of this changed. This is the day that the NSA murdered the President (this is the conclusion that I have come to after about 45 years of studying the event). Up until that evening I had never heard of the word President but I watched my Mom and my Dad grieve over his murder, up until that time I had never even heard of the word murder before. But, I understood that word as of that evening and I understood who and what a President was from the news that we were all now watching on TV and from the conversations my parents and grandparents were having about the event. This is how I remember being ‘woke up’ to the world outside my own little country bumpkin existence. 53 years ago today I also believe that most of the American people woke up to the reality that our own government had murdered our own President. The next big reality shaker was our government’s involvement in pretty much all of South-East Asia. The 1960’s were a wakeup call to most of America, it was when we learned that there was no way to believe anything that our so-called Leaders were telling us. 53 years ago today I lost my innocence, as did most of the American people.