Filipino science scholars are not only discovering or excelling in many fields around us—on Earth. They are also making waves in other fields—including those in the universe.

A Department of Science and Technology-Science Education Institute  (DOST-SEI) scholar-graduate is now making waves in the international astronomical world after leading a team that discovered the largest number of supermassive quasars in the centers of galaxies in the universe.

Reinabelle Reyes, a Ph.D. student at Princeton University and a BS Physics summa cum laude graduate at the Ateneo de Manila University in 2005, led a team of Sloan Digital Sky Survey (SDSS) II scientists that discovered a large number of “hidden quasars” that are shrouded in light-absorbing dust and gas, an SEI press release said.

According to Reyes, her team found around 900 hidden quasars, which is by far the largest sample ever found.

“A large survey like SDSS-II is important because quasars are about 10,000 times rarer than normal galaxies,” explained Reyes in a press release posted by SDSS in its web site.

Reyes is the lead author of the paper describing the results of the team’s study, entitled “Space Density of Optically-Selected Type 2 Quasars,” presented on January 9 at the American Astronomical Society meeting in Austin, Texas, and submitted for publication in the Astronomical Journal.

The word quasar is short for “quasi-stellar radio source,” the National Aeronautics and Space Administration (Nasa) said in its web site. This name, which means star-like emitters of radio waves, was given in the 1960s when quasars were first detected. The name is retained today, even though astronomers now know most quasars are faint radio emitters.

“We determined how common hidden quasars are, especially the most luminous ones. Perhaps more interestingly, we determined how common they are relative to normal quasars,” said team member Nadia Zakamska, a Nasa Spitzer Fellow at the Institute for Advanced Study in Princeton, as quoted by the SDSS press release.

“We found that hidden quasars make up at least half of the quasars in the relatively recent universe, implying that most of the powerful black holes in our neighborhood had previously been unrecognized.”

Michael Strauss, a Princeton University professor, explained that powerful black holes are more common in the last eight billion years of cosmic history than had previously been thought, SDSS said.

“Moreover, because the light from these hidden quasars had previously been unaccounted for, black holes turn out to be more efficient in converting the energy of in-falling matter into light than we had thought,” Strauss, as quoted by SDSS, said.

SDSS said this result also has implications for theoretical models of quasars.

“The relative numbers of hidden versus normal quasars tell us something about how dust and gas are typically distributed around these objects,” explained Julian Krolik, a collaborator from Johns Hopkins University. “If the dust covers a large fraction of the area around a black hole, this object would more likely appear as a hidden quasar. So the large number of hidden quasars discovered by the SDSS team implies that most of the light emitted by quasars is actually obscured,” Krolik was quoted by SDSS as saying.

Reyes said their project is the culmination of the graduate thesis work of her coauthor, Zakamska, a long-term postdoctoral fellow at the Institute of Advanced Study, under the supervision of Strauss, the SEI said.

THESE pictures show galaxies that host three of the hidden quasars found in the Sloan Digital Sky Survey (SDSS-II) sample. In every image, the quasar is at the center of the galaxy, but our view to it is obscured by dust. In the central image, the blue patches of light serve as an indirect indicator of the hidden quasar in the center of the galaxy. The same signature, although fainter, can be seen in the image on the left. The unusual shape of the right-most galaxy indicates that this object is undergoing interactions with a smaller galaxy that is being ripped apart. These images were obtained using the Advanced Camera for Surveys onboard the Hubble Space Telescope. --SDSS COLLABORATION, NADIA ZAKAMSKA,
INSTITUTE FOR ADVANCED STUDIES

Nasa said in its web site that many astronomers believe that quasars are the most distant objects yet detected in the universe. Quasars give off enormous amounts of energy—they can be a trillion times brighter than the sun or more than 100 normal galaxies combined!

Quasars are believed to produce their energy from massive black holes in the center of the galaxies in which the quasars are located, Nasa said. Because quasars are so bright, they drown out the light from all the other stars in the same galaxy.

Despite their brightness, due to their great distance from Earth, no quasars can be seen with an unaided eye, Nasa said. Energy from quasars takes billions of years to reach the Earth’s atmosphere.

For this reason, the study of quasars can provide astronomers with information about the early stages of the Universe.

In addition to radio waves and visible light, quasars also emit ultraviolet rays, infrared waves, X-rays and gamma rays. Most quasars are larger than our solar system. A quasar is approximately 1 kiloparsec in width.

Director Ester Ogena of the DOST-SEI said in the SEI press release that Reyes’s success in her career is a glaring example of the quality of scholar-graduates the country produces and the vast potential the Philippines has in space science.

“We hope our students would be able to get inspiration from Reyes and pursue a career in the sciences that will hopefully add to the roster of our great astronomers and space scientists,” she said.

Reyes urged students to venture into astronomy and astrophysics and pursue a fruitful and fulfilling career path in the sciences.

“Go for it—astronomy and astrophysics are rich and exciting fields that offer plenty of opportunities for young scientists to contribute. Master the basics, keep up with the latest discoveries, don’t stop asking questions—and finding answers,” she said.

The DOST-SEI has laid the groundwork for a Philippine Space Education Program (PSEP) in the country following a designation by the United Nations Educational, Scientific and Cultural Organization-Paris to act as focal point for its space-education program and related activities in the Philippines. It aims to promote science and technology, particularly space science, to Filipino students.

The PSEP also seeks to engage Filipinos in the exploration of space science, and technology and the process of science in various disciplines in an effort to create an educated public and to generate future space science explorers.

Likewise, the PSEP aims to create awareness among the students in career opportunities in the various fields of science and engineering, including space science, that would raise standards and address skills shortages, and be able to help in national development.

It also aspires to establish linkages and partnership with space organizations and institutions for possible assistance and collaboration in space-science education programs and projects. (With Lyn Resurreccion)

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