Tag Archives: lick observatory

The Supernova That Cried Wolf

A luminous supernova in a galaxy 67 million light years away from us has finally exploded for good, a UA-led team of astronomers has discovered. This event sheds light on how massive stars end their lives.

Astronomers have announced that a massive star, which they have watched repeatedly mimic a supernova since 2009, has finally exploded for real.

The report was presented at the American Astronomical Society meeting in Long Beach, Calif. by Jon Mauerhan of the Steward Observatory at the University of Arizona, in collaboration with Nathan Smith, also of the UA, and Alex Filippenko of the University of California, Berkeley.

The result is of special interest because it provides new critical information on the final death throes of massive stars in the years leading up to their explosion. The work has been accepted for publication in the Monthly Notices of the Royal Astronomical Society. (more…)

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How Galaxies Grow Up

A study of 544 star-forming galaxies shows that disk galaxies like our own Milky Way reached their current state as orderly rotating pinwheels much later than previously thought, long after much of the universe’s star formation had ceased.

Galaxies are in no hurry to grow up, a team of astronomers has discovered. A comprehensive study of hundreds of galaxies observed by the Keck telescopes in Hawaii and NASA’s Hubble Space Telescope has revealed an unexpected pattern of change that extends back 8 billion years, or more than half the age of the universe.

Researchers say the distant blue galaxies they studied are gradually transforming into rotating disk galaxies like our own Milky Way. Until now, it had not been clear how a galaxy’s organization and internal motion change over time, said Benjamin Weiner, assistant astronomer at the UA Steward Observatory and co-author of the paper describing the findings, which are published in The Astrophysical Journal. (more…)

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Supernovae of the Same Brightness, Cut From Vastly Different Cosmic Cloth

Berkeley Lab researchers make historic observation of rare Type 1a Supernova

Exploding stars called Type 1a supernova are ideal for measuring cosmic distance because they are bright enough to spot across the Universe and have relatively the same luminosity everywhere. Although astronomers have many theories about the kinds of star systems involved in these explosions (or progenitor systems), no one has ever directly observed one—until now.

In the August 24 issue of Science, the multi-institutional Palomar Transient Factory (PTF) team presents the first-ever direct observations of a Type 1a supernova progenitor system. Astronomers have collected evidence indicating that the progenitor system of a Type 1a supernova, called PTF 11kx, contains a red giant star. They also show that the system previously underwent at least one much smaller nova eruption before it ended its life in a destructive supernova. The system is located 600 million light years away in the constellation Lynx. (more…)

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