Focus
on Research
Penn State Intercom......June
7, 2001
Explosions
create
'superbubbles' in space
By
Barbara Kennedy
Eberly
College of Science
In a galaxy 7 billion light years from Earth, at a time when our sun was just being born, several thousand stars died in massive explosions that blasted giant "superbubbles" into the surrounding clouds of gas and dust.
The
discovery was presented to the scientific community by undergraduate Nicholas
A. Bond in colla
boration
with astronomers Christopher W. Churchill and Jane C. Charlton and Steven
S. Vogt of the University of California at Santa Cruz.
"A superbubble is a huge, roughly spherical region 10,000 trillion miles across, where thousands of exploding stars have literally blown a hole in the gaseous medium between the stars," according to Bond, an astronomy major in his junior year, who said his team's research reveals that as many as six of these superbubbles formed at nearly the same time in the galaxy.
Charlton, associate professor of astronomy and astrophysics, added, "The energy released by the dying stars in those moments that created these gigantic holes is equivalent to the output of 10,000 suns over their entire 10-billion-year lifetimes."
"In a Hubble Space Telescope image we can see the shape and size of the young galaxy from the light of its shining stars; however, we can't actually see the Swiss-cheese structure of these superbubbles because the stars whose explosive deaths created it are no longer lighting it up," said Churchill, a research associate in the Department of Astronomy and Astrophysics. The clue that led to the detection of the invisible holes was the astronomers' discovery of the superbubbles' fingerprints -- a unique pattern of "absorption lines" -- in the spectrum of a quasar whose thin beam of light passes through the galaxy before it reaches Earth.
"We use quasars, which are more luminous than a trillion suns and lie at the outer edges of the universe, as deep-space flashlights," Churchill explained. The absorption-line pattern in the quasar's spectrum revealed the signature "shadow" of the superbubbles along the narrow channel illuminated through the galaxy by the quasar's light. "The striking pattern from this galaxy is several absorption-line pairs, each having a velocity separation of 70,000 miles per hour, which is a gauge of the speed at which the opposite sides of the superbubbles are flying apart," Churchill said.
"We investigated the alternative possibility that two or three galaxies in a small group were giving rise to the absorption-line pairs, but these scenarios could not satisfactorily explain the observations," explained primary investigator Bond. "Superbubbles are the most plausible mechanism through which such evenly split absorption-line pairs could have been created."
Astronomers use radio waves to directly observe emissions from superbubbles in our Milky Way galaxy and in nearby galaxies, but this technique is not adequate for detecting superbubbles in very distant galaxies. The team said their discovery with quasar light provides the best evidence yet for the existence of superbubbles in a galaxy so distant from Earth. The quasar's light, which took 7 billion years to reach Earth after it passed through the superbubble regions, provides a snapshot of how the galaxy looked 7 billion years ago, when it was undergoing mass stellar death.
The quasar, named MC 1331+170, is located in the constellation of Coma Berenices, in the northern sky near the star Arcturus in Bootes, as is the galaxy in which the superbubbles were discovered.
Barbara Kennedy can be reached at bkk1@psu.edu.
Study: Vitamin
D may
benefit MS victims
A small study conducted by University re-searchers and Helen Hayes Hospital in New York has shown that a daily dose of vitamin D -- 1,000 IU or two and a half times the recommended adult dose -- causes blood chemistry changes that indicate positive effects for multiple sclerosis patients.
Margherita Cantorna, assistant professor of nutrition, says the study has not been in progress long enough to observe changes in the clinical symptoms of the disease in the patients who participated. However, blood samples drawn after just six months of vitamin D supplementation, show an increase in transforming growth factor beta-1 (TGF-Beta) which is associated with the remission and suppression of the immune response which produces symptoms in MS patients. Researchers also found a decrease in interleuken-2 which is associated with the cells that induce MS.
"I think that if you are an MS patient, it would be best to continue to follow your personal physician's advice," Cantorna said. "Since vitamin D can be toxic in high doses, it would not be a good idea to begin taking vitamin D pills available over the counter in large amounts."
The results were detailed at the Experimental Biology 2001 conference in Orlando, Fla. The paper was co-authored by Dr. Felicia Cosman, medical director, Clinical Research Center, S. A. Gordon and J. Cruz, all of Helen Hayes Hospital, and Cantorna. Cantorna's student, Brett Mahon, a doctoral candidate in nutrition, is first author.
Religious dads spend more time with kids
By
Paul Blaum
Public Information
Religious fathers, whether married or divorced, are more involved with their children than nonreligious fathers and report higher quality relationships as parents, according to a University study.
"The influence of religiosity on father involvement should not be overstated," said Valarie E. King, assistant professor of sociology, demography and human development and family studies. "Certainly many nonreligious fathers have good relationships with their children, and religion is only one of the many factors that influence father involvement."
"Religious fathers report putting more thought and effort into their relationships with their children, feeling more of an obligation for contact with them and having higher expectations of a continued good relationship with offspring," she said.
The University researcher discovered that religion itself helps fathers be better fathers, not traditional views of marriage and children. Her findings suggest two arguments against automatically equating religiosity and traditional beliefs about marriage. First, her data reveals that, while religious men place a high priority on marriage and family, they also take the view that husbands should share equally in housework and child raising.
Second, the data shows that mainstream Protestants and Catholics are equally involved with their children as conservative Protestants, supposedly the most vocal proponents of traditional family values. In the case of divorced dads, conservative Protestants are less likely than other Protestants to assist their adult children or grandchildren with help around the house, transportation and child care.
The study's data is from the 1995 National Survey of Mid-life Development in the United States. The sample included 647 married and 163 divorced men.
Paul
Blaum can be reached at pab15@psu.edu.
Astronomers
confirm
grad
student's research
Astronomers at the Harvard-Smithsonian Center for Astrophysics have published research results that provide confirmation of a common feature among quasars, which are growing, supermassive black holes that gobble up matter at a rate of more than one solar mass each year and produce enormous amounts of energy and light.
The researchers' results, based on observations made with the Chandra X-ray Observatory, confirm results published earlier by a team led by Sarah Gallagher, a graduate student at Penn State.
According to Gallagher's research, "shrouded" quasars, those that are seen through material blowing off the accretion disk in an energetic wind, do produce important X-ray emissions. Her research showed definitively for the first time that there was absorption of X-rays by material along the line of site and the researchers from the Harvard-Smithsonian Center for Astrophysics have confirmed this result with a larger sample.
She made her initial findings in 1999 and 2000 with the Advanced Satellite for Cosmology and Astrophysics (ASCA), a joint project between NASA and Japan that has since fallen back to Earth, and has been working on extending those results using Chandra.
"You can think of the quasar as being sort of a messy eater," Gallagher said. "It does not eat everything that comes close to the black hole and maybe it spits out as much as it eats as a wind coming off the accretion disk. If you look through the wind, then you see a 'shrouded' quasar."