(Press-News.org) Observations with CSIRO's Australia Telescope Compact Array have confirmed that astronomers have found the first known "middleweight" black hole.
Outbursts of super-hot gas observed with a CSIRO radio telescope have clinched the identity of the first known "middleweight" black hole, Science Express reports online today.
Called HLX-1 ("hyper-luminous X-ray source 1"), the black hole lies in a galaxy called ESO 243-49, about 300 million light-years away.
Before it was found, astronomers had good evidence for only supermassive black holes — ones a million to a billion times the mass of the Sun — and "stellar mass" ones, three to thirty times the mass of the Sun.
"This is the first object that we're really sure is an intermediate-mass black hole," said Dr Sean Farrell, an ARC Postdoctoral Fellow at the University of Sydney and a member of the research team, which included astronomers from France, Australia, the UK and the USA.
CSIRO's Dr Ron Ekers, who studies supermassive black holes in the centres of galaxies, said "We don't know for sure how supermassive black holes form, but they might come from medium-size ones merging. So finding evidence of these intermediate-mass black holes is exciting."
HLX-1 was discovered by chance in 2009, because it stood out as a very bright X-ray source.
As gas from a star or gas cloud is being sucked into a black hole, it is heated to extreme temperatures and shines in X-rays.
"A number of other bright X-ray sources have been put forward as possibly being middleweight black holes. But all of those sources could be explained as resulting from lower mass black holes," Dr Farrell said. "Only this one can't. It is ten times brighter than any of those other candidates. We are sure this is an intermediate-mass black hole — the very first."
Since 2010 the researchers have been studying the black hole with CSIRO's Compact Array radio telescope near Narrabri, NSW.
"From studying other black holes we know that sucking in the gas creates X-rays, but there's then a sort of reflux, with the region around the black hole shooting out jets of high-energy particles that hit gas around the black hole and generate radio waves," said Dr Farrell.
"So what we tend to see is the X-ray emission and then, a day or two or even a few days later, the source flaring up in radio waves."
By looking at the source's X-ray output, the researchers predicted two occasions when it should also be brightening in radio waves — and they were right both times.
Dr Farrell speculates that a companion star traverses a very eccentric orbit around the black hole. When the companion comes close, the black hole strips gas from its partner, and it is this that gives rise to the X-ray flaring.
The brightness of the X-ray and radio flares have allowed the team to put an upper limit on the mass of the black hole of 90,000 times the mass of the Sun. However, Dr Farrell says that this is a conservative estimate, and for a variety of reasons a lower figure of around 20,000 solar masses is more likely.
Why have we found only this one confirmed intermediate-mass black hole? "There maybe lots of others out there that are not currently feeding, and so are not detectable, or are feeding at a very low rate, so they don't stand out as intermediate-mass black holes," Dr Ekers said.
HLX-1 may have been the central black hole of a low-mass "dwarf" galaxy, Dr Farrell speculates; a dwarf galaxy that was swallowed by the larger galaxy ESO 243-49, just as our own Milky Way Galaxy has swallowed dwarf galaxies. There is evidence of star-formation about HLX-1, which would be consistent with a "plunging dwarf". The research team is now looking for other signs of disturbance around the site of the black hole, such as gas streams, which would also support this idea.
### END
Belching black hole proves a biggie
2012-07-10
ELSE PRESS RELEASES FROM THIS DATE:
Study reveals good news about the GI of rice
2012-07-10
Research analysing 235 types of rice from around the world has found its glycemic index (GI) varies from one type of rice to another with most varieties scoring a low to medium GI.
This finding is good news because it not only means rice can be part of a healthy diet for the average consumer, it also means people with diabetes, or at risk of diabetes, can select the right rice to help maintain a healthy, low GI diet.
The study found that the GI of rice ranges from a low of 48 to a high of 92, with an average of 64, and that the GI of rice depends on the type of rice ...
July/August 2012 Annals of Family Medicine tip sheet
2012-07-10
Opioid Use and Misuse for Chronic Pain: What is the Appropriate Role of Prescription Painkillers?
A cluster of articles in the July/August issue of Annals looks at opioid use for the management of chronic pain, including the escalating levels of misuse, overdose and addiction associated with opioid pain relievers. The role of opioids in the management of chronic pain is timely and consequential — the volume of prescribed opioids has increased 600 percent from 1997 to 2007, and during roughly the same period, the number of unintentional lethal overdoses involving prescription ...
Annals of Internal Medicine tip sheet for July 10, 2012, online issue
2012-07-10
1. Free Curriculum Aims to Educate Internal Medicine Residents About Wasteful Health Care Spending
Developed by the American College of Physicians and the Alliance for Academic Internal Medicine, the New Curriculum is Part of ACP's Ongoing High-Value, Cost-Conscious Care Initiative
Economists warn that health care spending in the United States is rising at an unsustainable rate. To slow the rate of increase, while preserving high quality care, thought leaders in academic medicine suggest that clinicians focus on using medical interventions that provide good value. This ...
JCI early table of contents for July 9, 2012
2012-07-10
Breathing easy: keeping airways open
Asthma is an increasingly common chronic disorder characterized by wheezing and shortness of breath. Symptoms are caused by excessive airway smooth muscle contraction; however mechanisms serving to keep airways open are not fully understood. Dean Sheppard and colleagues at the University of California at San Francisco have revealed a pathway required for preventing exaggerated airway smooth muscle contraction. Their work investigates a protein called α9β1, which is highly expressed in airway smooth muscle, and makes use ...
Decreasing cancer risk associated with inflammatory bowel disease
2012-07-10
Inflammatory bowel disease is caused by chronic inflammation , which leads to damage of the intestinal epithelium. Patients with inflammatory bowel disease have an elevated risk for developing colorectal cancer because of this chronic inflammation. In an effort to develop strategies to break the cycle of inflammation, Dr. Brent Polk and colleagues at the University of Southern California in Los Angeles examined two mouse models of colorectal cancer. Their work shows that inactivating a key receptor, known as epidermal growth factor receptor, increases the frequency and ...
New silk technology preserves heat-sensitive drugs for months without refrigeration
2012-07-10
MEDFORD/SOMERVILLE, Mass. (July 9, 2012, 3 PM EST) Researchers at Tufts University School of Engineering have discovered a way to maintain the potency of vaccines and other drugs -- that otherwise require refrigeration -- for months and possibly years at temperatures above 110 degrees F, by stabilizing them in a silk protein made from silkworm cocoons. Importantly, the pharmaceutical-infused silk can be made in a variety of forms such as microneedles, microvesicles and films that allow the non-refrigerated drugs to be stored and administered in a single device.
The ...
Marcellus brine migration likely natural, not man-made
2012-07-10
A Duke University study of well water in northeastern Pennsylvania suggests that naturally occurring pathways could have allowed salts and gases from the Marcellus shale formation deep underground to migrate up into shallow drinking water aquifers.
The study found elevated levels of salinity with similar geochemistry to deep Marcellus brine in drinking water samples from three groundwater aquifers, but no direct links between the salinity and shale gas exploration in the region.
"This is a good news-bad news kind of finding," said Avner Vengosh, professor of geochemistry ...
Generic drugs key to US overseas HIV relief
2012-07-10
PROVIDENCE, R.I. [Brown University] — The President's Emergency Plan for AIDS Relief (PEPfAR) began in 2003 with good intentions, but it was not until the U.S. government's massive overseas public health campaign adopted generic drugs that it became a success, according to a new article by Brown University researchers in the July issue of the journal Health Affairs. Nearly a decade later, expanding the availability of generics remains urgent, especially as doctors in the field encounter resistance to first-line treatment regimens.
"By 2002 generic drugs had been shown ...
Uncircumcised boys at higher risk of urinary tract infections
2012-07-10
Uncircumcised boys are at higher risk of urinary tract infection, regardless of whether the urethra is visible, found a new study published in CMAJ (Canadian Medical Association Journal).
Urinary tract infections are one of the most common serious bacterial infections in children and, if not treated, can cause an infection of the blood or scar the kidneys.
To determine whether the risk for infection is higher in boys with a visible urethral meatus, researchers looked at a cross-section of 393 boys who visited an emergency department with symptoms of a possible urinary ...
Canada's Bill C-31 to change immigration act could severely affect mental health of refugees
2012-07-10
The Canadian government's proposed Bill C-31 to change the country's immigration act could have serious negative impacts on the mental health of refugees, states a commentary in CMAJ (Canadian Medical Association Journal).
Under the proposed Bill C-31, the Protecting Canada's Immigration System Act, which targets refugee claimants, children under age 16 will be separated from their parents or held informally in a detention centre with their mothers. Family reunification for recognized refugees will be delayed until five years and detention reviews will not occur for ...