NASA's Swift Satellite Discovers A New Black Hole In Our Galaxy
"The pattern we're seeing is observed in X-ray novae where the central object is a black hole. Once the X-rays fade away, we hope to measure its mass and confirm its black hole status," said Boris Sbarufatti, an astrophysicist at Brera Observatory in Milan, Italy, who currently is working with other Swift team members at Penn State in University Park, Pa.
The black hole must be a member of a low-mass X-ray binary (LMXB) system, which includes a normal, sun-like star. A stream of gas flows from the normal star and enters into a storage disk around the black hole. In most LMXBs, the gas in the disk spirals inward, heats up as it heads toward the black hole, and produces a steady stream of X-rays.
But under certain conditions, stable flow within the disk depends on the rate of matter flowing into it from the companion star. At certain rates, the disk fails to maintain a steady internal flow and instead flips between two dramatically different conditions -- a cooler, less ionized state where gas simply collects in the outer portion of the disk like water behind a dam, and a hotter, more ionized state that sends a tidal wave of gas surging toward the center.
"Each outburst clears out the inner disk, and with little or no matter falling toward the black hole, the system ceases to be a bright source of X-rays," said John Cannizzo, a Goddard astrophysicist. "Decades later, after enough gas has accumulated in the outer disk, it switches again to its hot state and sends a deluge of gas toward the black hole, resulting in a new X-ray outburst."This phenomenon, called the thermal-viscous limit cycle, helps astronomers explain transient outbursts across a wide range of systems, from protoplanetary disks around young stars, to dwarf novae -- where the central object is a white dwarf star -- and even bright emission from supermassive black holes in the hearts of distant galaxies.
Select the service that is right for you!COMPARE ALL SERVICES
Jim Cramer and Stephanie Link actively manage a real portfolio and reveal their money management tactics while giving advanced notice before every trade.
- $2.5+ million portfolio
- Large-cap and dividend focus
- Intraday trade alerts from Cramer
- Weekly roundups
Access the tool that DOMINATES the Russell 2000 and the S&P 500.
- Buy, hold, or sell recommendations for over 4,300 stocks
- Unlimited research reports on your favorite stocks
- A custom stock screener
- Upgrade/downgrade alerts
Jim Cramer's protege, David Peltier, identifies the best of breed dividend stocks that will pay a reliable AND significant income stream.
- Diversified model portfolio of dividend stocks
- Alerts when market news affect the portfolio
- Bi-weekly updates with exact steps to take - BUY, HOLD, SELL
All of Real Money, plus 15 more of Wall Street's sharpest minds delivering actionable trading ideas, a comprehensive look at the market, and fundamental and technical analysis.
- Real Money + Doug Kass Plus 15 more Wall Street Pros
- Intraday commentary & news
- Ultra-actionable trading ideas
Our options trading pros provide daily market commentary and over 100 monthly option trading ideas and strategies to help you become a well-seasoned trader.
- 100+ monthly options trading ideas
- Actionable options commentary & news
- Real-time trading community
- Options TV