Lon Spight rememberance Friday August 28, 2015; 3:30-6:30 BPB-102

The Department of Physics & Astronomy will host an informal memorial for our recently departed friend and colleague Dr. Lon Spight -- one of the founders of our department.

August 21, 2015 10:00AM BPB-217. Wei-Hua Lei, On-beam and Off-beam Jetted TDEs.

A star or sub-stellar object will be destroyed by tidal forces when it passes close enough by a supermassive black hole (SMBH). These events, known as tidal disruption events (TDEs), are expected to produce luminous flare emission in the UV to X-ray band. Recent observations of Sw J1644+57, in particular, suggest that at least some TDEs can launch a relativistic jet. A common speculation is that these rare events are related to rapidly spinning BHs. We constrained the BH spin parameter by using the available data, and found that the BH indeed carries a moderate to high spin, suggesting that BH spin is likely the crucial factor behind the Sw J1644+57-like events. Other observational properties include the rough 2.7 day periodicity in X-ray dips and 200s QPO, which we interpret as due to precession of the jet. In addition, Sw J2058+05 and Sw J1112.2-8238 are also thought to be a TDE with an on-beam relativistic jet. It is natural to expect that there should be some events with off-beam ones. We will present the first candidate for such off-beam jetted TDEs

Ye Li's work on life in the early universe discussed in New Scientist

Yi Li and Bing Zhang's paper due to be published in The Astrophysical Journal: Can life survive Gamma-Ray Bursts in the high-redshift universe?, is discussed in a daily news article in The New Scientist. That article is titled: Giant old galaxies, not Milky Ways, are best for life to thrive.