After 16 years of observations of hundreds of cosmic X-ray sources, the Rossi X-ray timing Explorer was turned off and ceased operations. The High Energy X-ray Timing Experiment, conceived, designed, and built at UCSD, was one of three instruments aboard RXTE. RXTE opened the realm of time domain astrophysics with sub-millisecond timing of accreting neutron stars, magnetars, and Galactic black holes, thousands of monitoring observations revealing details on the spectral states and variability of active galaxies and micro-quasars, and all-sky monitoring of persistent and transient sources. The rapid response of RXTE to unpredictable cosmic events was a hallmark of the mission. Read More

Astronomers at Pennsylvania State University, UCSD and Carnegie Observatories, including CASS's Adam Burgasser, have confirmed the existence of an extremely low-temperature companion to the nearby white dwarf WD 0806-661. With an estimated temperature between 80 and 160 F, WD 0806-661B is the only directly detected companion to a star with a temperature similar to Earth's. In addition, its mass is only 7 times that of Jupiter, so it is unclear whether WD 0806-661B should be called a brown dwarf or a planet. Read More

A new study has shown that rapidly growing supermassive black holes, known as active galactic nuclei, are found in every kind of galaxy - massive and smaller, old elliptical red galaxies and younger blue spirals - exonerating active galactic nuclei as a suspect in the quenching of star formation in galaxies. The study, led by CASS postdoc James Aird, searched for X-rays from active galactic nuclei within PRIMUS, a large-scale survey to map the distances of over 100,000 galaxies that involves many CASS members. Read More

NASA today launched a pair of small spacecraft that will give middle-school students an unprecedented opportunity to study the moon by way of cameras guided by undergraduates at UC San Diego. The university will use software to project the path that the GRAIL spacecraft will follow while orbiting the moon next year. Middle-school students can ask UCSD to use the spacecraft's MoonKam imaging systems to photograph specific spots on the surface. CASS Researcher Karen Flammer is involved in education and outreach for the GRAIL mission. Read More

CASS Postdoctoral Fellow Dr. Carl Melis has helped identify the nearest "baby" star, a 40 million-year-old pre-main sequence star called AP Columbae. The cool red dwarf star is about 1000 times less luminous that our Sun, and is located a mere 27 light-years from Earth in a newly recognized group of stars known as the Argus/IC 2391 association. The study appears in this month's issue of the Astronomical Journal. Read More