Brian Cameron pbc[at] astro.caltech.edu Caltech Astronomy Department Mail Stop, 105-24 Phone 626.395.4095 Fax: 626.568.9352 CV: in pdf format. Quick References

Research Interests Hello! I'm a fifth year graduate student in astrophysics at Caltech working with Shri Kulkarni. Below you will find a little more information on my work. I have a variety of astrophysical research interests that span the electromagnetic spectrum from low-frequency radio to X-rays. I'm always looking to learn new and fun techniques and apply them to interesting problems, which thus far has mainly been to study compact objects. Laser Guide Star Adaptive Optics - My AO Page My recently defended thesis project involves the development, characterization and exploration of Laser Guide Star Adaptive Optics (LGS-AO) at Keck (image right) and Palomar for astrometry. Astrometry is simply the measurement of the positions of celestial objects. We can study the motions of these objects in order to understand their formation, dynamics and evolution. Laser guide star adaptive optics allow us to correct for atmospheric turbulence by using a laser to create an artificial star roughly 100 km above the Earth's surface. This compensation allows us to achieve near diffraction limited imaging with the world's largest ground-based telescopes which simultaneously increases the signal-to-noise ratio and shrinks the image size. For the first part of my thesis I will measure proper motions of an interesting sample of compact objects including 'magnetars', accreting neutron stars and black holes. This will give us an insight into the supernova explosions that gave forged these objects, as well as the sites of their formation. The second part of my thesis will be to answer the question: What is the limiting precision of ground-based astrometry with adaptive optics? There are many difficulties in measuring positions with AO that stem from the physical optics (e.g. optical distortions, intrapixel variability in CCDs) and the atmosphere (e.g. anisoplantism, differential chromatic refraction). I will study the effect of each of these on the measurement of a stellar position. Cosmic Explosions On December 27, 2004 every high energy detector in space was saturated by the most intense X-ray flare detected by man (here's a nice NASA movie, but this one is pretty good considering SWIFT didn't actually slew to the burst since it was too close to the Sun!). It was so bright that at a distance of 30,000 light-years it affected the Earth's ionosphere. It came from the highly magnetic neutron star SGR 1806-20 (right is an artist's concept of such a 'magnetar'). I discovered the bright radio emission from the aftermath of this explosion with Dale Frail, and was part of an international team that followed the source with radio telescopes in the U.S., Australia, Europe and Japan (Cameron et al., 2005 in Nature). This project piqued my interest in cosmic explosions. Last year I was part of a team that helped localize afterglows (particularly radio and X-ray) of the enigmatic short hard GRBs (Fox et al., 2005 in Nature and Berger et al., 2005 in Nature). Currently, I'm working on a small fun project to try and detect the dispersed prompt radio signal from GRBs (if it exists!) with low-frequency radio receivers at the VLA. 47 Tucanae Along with Bob Rutledge, I'm involved in a large program to study the variability of X-ray sources in the rich globular cluster 47 Tuc with the High Resolution Camera on the Chandra X-ray Observatory. I'm mainly interested in the variability of the 19 known localized millisecond pulsars. High time resolution imaging is an important piece of the puzzle for determining the origin of the high energy radiation streaming from these objects. Looking at the future of X-ray astronomy, this may be the largest study of globular cluster millisecond pulsars for a generation. The image to the right is what 47 Tuc looks like with X-ray eyes (Grindlay et al., with Chandra ACIS).