‘Cosmic Flashlight’ Makes Gas Glow Like A Fluorescent Light Bulb

Funny how a single quasar can illuminate — literally and figuratively — some of the mysteries of the universe. From two million light-years away, astronomers spotted a quasar (likely a galaxy with a supermassive black hole in its center) shining on a nearby collection of gas or nebula. The result is likely showing off the filaments thought to connect galaxies in our universe, the team said.

“This is a very exceptional object: it’s huge, at least twice as large as any nebula detected before, and it extends well beyond the galactic environment of the quasar,” stated Sebastiano Cantalupo, a postdoctoral fellow at the University of California Santa Cruz who led the research.

The find illuminated by quasar UM287  could reveal more about how galaxies are connected with the rest of the “cosmic web” of matter, astronomers said. While these filaments were predicted in cosmological simulations, this is the first time they’ve been spotted in a telescope.

“Gravity causes ordinary matter to follow the distribution of dark matter, so filaments of diffuse, ionized gas are expected to trace a pattern similar to that seen in dark matter simulations,” UCSC stated.

A graphic showing how matter in the universe could be distributed. Some astronomers believe matter is sprinkled as a a "cosmic web" of filaments. The larger section shows a dark-matter simulation (by Anatoly Klypin and Joel Primack) and the inset a smaller portion, 10 million light-years across, from another simulation that also includes gas (S. Cantalupo).  Credit:  S. Cantalupo (UCSC), Joel Primack (UCSC) and Anatoly Klypin (NMSU).
A graphic showing how matter in the universe could be distributed. Some astronomers believe matter is sprinkled as a a “cosmic web” of filaments. The larger section shows a dark-matter simulation (by Anatoly Klypin and Joel Primack) and the inset a smaller portion, 10 million light-years across, from another simulation that also includes gas (S. Cantalupo). Credit: S. Cantalupo (UCSC), Joel Primack (UCSC) and Anatoly Klypin (NMSU).

Astronomers added that it was lucky that the quasar happened to be shining in the right direction to illuminate the gas, acting as a sort of “cosmic flashlight” that could show us more of the underlying matter. UM287 is making the gas glow in a similar way that fluorescent light bulbs behave on Earth, the team added.

“This quasar is illuminating diffuse gas on scales well beyond any we’ve seen before, giving us the first picture of extended gas between galaxies,” stated J. Xavier Prochaska, coauthor and professor of astronomy and astrophysics at UC Santa Cruz. “It provides a terrific insight into the overall structure of our universe.”

The find was made using the 10-meter Keck I telescope at the W. M. Keck Observatory in Hawaii. You can check out more details on the discovery on the Keck Observatory’s website or at this press release from the Max Planck Institute for Astronomy in Heidelberg, Germany.

The research was published in the Jan. 19 edition of Nature and available in preprint version on Arxiv.

White Dwarf Stars Consume Rocky Bodies

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“I love rocky road… So won’t you buy another gallon, baby…” Yeah. We all love rocky road ice cream, but what do stars like to snack on? In the case of the white dwarf star it would appear that a rocky body – similar to Earth – could be a preferred blend. At one time astronomers thought the dense, elderly stars were just gathering dust… but apparently it’s the “bones” left-over from a planetary knosh.

Using the Keck I telescope on Mauna Kea in Hawaii, astronomer and study coauthor Ben Zuckerman of UCLA and his team have been studying two helium-dominated white dwarfs – stars PG1225-079 and HS2253+8023. About the size of Earth, but as massive as the Sun, these stars have a zone of “pollution” around them that’s around equal in mass to asteroid Ceres.

“This means that planet-like rocky material is forming at Earth-like distances or temperatures from these stars,” says Zuckerman. He also notes that it’s still unclear whether the material is from a planet, planet-like bodies or an asteroid, but it is clear that there’s a lot of it.

Because looking at a white dwarf star for evidence of solar systems wasn’t really a high priority consideration, these new findings could lend researchers some new clues. It’s not just dust – it’s dust with a signature. Because the white dwarf has a “clean” atmosphere of hydrogen or helium, finding other components in its spectra could point to a one-time presence of Earth-like planets. Zuckerman says that between 25 and 30 percent of white dwarfs have orbital systems that contain both large planets and smaller rocky bodies. After the dwarf forms, larger, Jupiter-mass planets can perturb the orbits of smaller bodies and bounce them toward the star.

“This is the first hint that despite all the oddball planetary systems we see, some of them must be more like our own,” says astronomer John Debes of NASA’s Goddard Space Flight Center in Greenbelt, Md., who was not involved in the study. “We think that most of these systems that show pollution must in some way approximate ours.”

How do they know if they have a candidate? Star PG1225-079 has a mix of elements, including magnesium, iron and nickel (along with others). These were found in ratios very similar in overall content of Earth. Star HS2253+8023 contains more than 85 percent oxygen, magnesium, silicon and iron. Not only are these assessments also similar to our planet, but found in the correct range where this type of rocky body should have formed.

“I’ve never seen so much detail in spectra,” says astronomer Jay Holberg of the University of Arizona in Tucson, who was not involved in the study. “People have seen iron and calcium and other things in these stars, but [this group has] gone off and found a whole slew of other elements.”

Pass the spoon… Before it melts.

Original Story Source: Science News Release.