No stars in the clouds

Jan 10, 2006

A team of astronomers from the University of Pittsburgh and the Universitäts-Sternwarte München in Munich, Germany, announced today in a paper presented at the meeting of the American Astronomical Society in Washington, D.C., that their search for dwarf galaxies in fast-moving clouds of gas has yielded no results, leading them to suggest alternative avenues of research to find the supposedly "missing" galaxies.

The team, which includes Regina Schulte-Ladbeck, associate dean for undergraduate studies and professor of physics and astronomy in Pitt's School of Arts and Sciences, and Ulrich Hopp of the Universitäts-Sternwarte München, has been searching for stars in high-velocity clouds. However, said Schulte-Ladbeck, "Our searches have come up empty."

The mathematical simulations that astronomers use to establish how galaxies were formed predict that every giant galaxy should have a few hundred "dwarf" galaxy companions. But in our own neighborhood, the Milky Way Galaxy, there are only 50 or so such dwarves.

One simple way to explain the difference would be if the missing dwarf galaxies were located in high-velocity clouds, astronomer Leo Blitz of the University of California, Berkeley, and his colleagues had suggested. Schulte-Ladbeck and Hopp hoped to measure the distances between the clouds and the Milky Way to obtain proof that the clouds indeed held additional satellite galaxies of our Milky Way.

To search for stars in the clouds, the researchers took a two-pronged approach. First, they used the Two Micron All Sky Survey, a survey conducted by the University of Massachusetts and funded primarily by NASA and the National Science Foundation, to look for bright stars in circular patches of sky two degrees across, the area typically covered by the gas clouds that make the most promising dwarf galaxy candidates.

Second, using accurate positions of where most of the hydrogen gas in several clouds is located--supplied to them by radio astronomer Jürgen Kerp of the University of Bonn--the researchers also trained one of the 8-meter (315-inch) telescopes of the European Southern Observatory's Very Large Telescope, located in northern Chile's Atacama Desert, on small regions within the clouds to search if any faint stars had formed there. However, neither of these methods turned up any stars.

In their paper, Schulte-Ladbeck and Hopp conclude that it is unlikely that hundreds of additional dwarf satellites of the Milky Way have been somehow "hiding" from observers, and they encourage astronomers to pursue other solutions to the discrepancy.

Source: University of Pittsburgh

Explore further: Heavy metal frost? A new look at a Venusian mystery

add to favorites email to friend print save as pdf

Related Stories

Slow-growing galaxies offer window to early universe

Oct 16, 2014

What makes one rose bush blossom with flowers, while another remains barren? Astronomers ask a similar question of galaxies, wondering how some flourish with star formation and others barely bloom.

NASA's RapidScat keeps a watchful eye on ocean storms

23 hours ago

On Sept. 20, NASA launched a sequel to a classic Earth science mission that was a hit with researchers and forecasters of hurricanes and other tropical cyclones. Unlike many Hollywood remakes, this one promises ...

The social web of things

20 hours ago

Research to be published in the International Journal of Web-Based Communities suggests that the familiar interfaces of online social networking sites might be adapted to allow us to interact more efficiently with our ne ...

Cosmic jets of young stars formed by magnetic fields

18 hours ago

Astrophysical jets are counted among our Universe's most spectacular phenomena: From the centers of black holes, quasars, or protostars, these rays of matter sometimes protrude several light years into space. ...

Construction secrets of a galactic metropolis

Oct 15, 2014

Galaxy clusters are the largest objects in the Universe held together by gravity but their formation is not well understood. The Spiderweb Galaxy (formally known as MRC 1138-262) and its surroundings have ...

Recommended for you

Heavy metal frost? A new look at a Venusian mystery

14 hours ago

Venus is hiding something beneath its brilliant shroud of clouds: a first order mystery about the planet that researchers may be a little closer to solving because of a new re-analysis of twenty-year-old ...

Exomoons Could Be Abundant Sources Of Habitability

18 hours ago

With about 4,000 planet candidates from the Kepler Space Telescope data to analyze so far, astronomers are busy trying to figure out questions about habitability. What size planet could host life? How far ...

Hot explosions on the cool sun

20 hours ago

(Phys.org) —The Sun is more spirited than previously thought. Apart from the solar eruptions, huge bursts of particles and radiation from the outer atmosphere of our star, also the cooler layer right below ...

User comments : 0